Department of Biomedical Engineering
Current   |   Events   |   Archive

 

News

2019

Congratulations, Jeffrey Capadona, PhD
Professor of Biomedical Engineering
Case Western Reserve University

The Cleveland FES Center congratulates Jeffrey Capadona, PhD on being promoted to Professor of Biomedical Engineering at Case Western Reserve University.

Dr. Capadona is an investigator at the Cleveland FES Center, APT Center, and Research Health Scientist at the Louis Stokes VA Medical Center. His lab is studying various aspects of microelectrode performance, and pursuing both materials-based and therapeutic-mediated methods to mitigate the inflammatory-mediated microelectrode failure mechanisms.

Case Western Reserve researchers discover new technique to prevent seizures. More

Rajat Shivaracharan wins the CWRU school of medicine doctoral excellence award with his thesis entitled:
"Self-Propagating, Non-Synaptic Hippocampal Waves Recruit Neurons by Electric Field Coupling"
Advisor: DM Durand

Nicholas Couturier win the 2019 Basic Science Epilepsia award for this paper entitled:
"Corpus callosum low-frequency stimulation suppresses seizures in an acute rat model of focal cortical seizures"

He will be flying to Bangkok Thailand, all expenses paid, to present his work at the International League against epilepsy conference.
Advisor: DM Durand

2018

Congratulations Bolu Ajiboye, PhD and Robert Kirsch, PhD
First Place - 2018 International Annual BCI-Research Award

The Cleveland FES Center congratulates Bolu Ajiboye, PhD and Robert Kirsch, PhD on receiving first place for the 2018 International Annual Brain Computer Interface (BCI) Research Award, for their project entitled "Restoring Functional Reach-to-Grasp in a Person with Chronic Tetraplegia using Implanted Functional Electrical Stimulation and Intracortical Brain-Computer Interfaces."

The Brain Computer Interface Award is one of the highest achievements in BCI research. It is an annual award organized by the BCI Foundation recognizing outstanding and innovative research in the field of Brain-Computer Interfaces.

Neural Engineering Center professors featured in a Nature review article on the future of Medicine

Bolu Ajiboye is in the news!


Seminars

2019

Friday, August 23, 2019
NEC Seminar

9:00 am, Wickenden 321
Speaker: Leah Marie Roldan
Advisors: Dr. Dustin Tyler
Title: Does modulation of pulse amplitude result in the same characteristics of perceived intensity as modulation of pulse width?

Abstract: Hand prostheses have the potential to help upper limb amputees perform everyday tasks, increase quality of life, and return to employment. Despite these benefits, abandonment of prostheses continues to be a problem. About 21% of upper limb amputees choose not to use any prosthetic devices and 85% of these individuals identify the absence of sensory feedback as a contributing factor. Flat Interface Nerve Electrodes (FINEs) and spiral cuff electrodes have been successfully implanted in four upper limb amputees, with stimulation through these electrodes providing subjects with somatosensory feedback. Additionally, this feedback can be controlled through a closed-loop system with pressure and bend sensors incorporated within a prosthetic hand. This technology has thereby restored tactile feedback and enabled participants to use prostheses to interact with objects and other people, as well as improved task performance. To better understand how sensation evoked by electrical stimulation is interpreted, psychophysical methods can be used to measure perceptual dimensions, such as perceived intensity. Previous work in our lab utilized a two-alternative forced-choice paradigm to investigate neural encoding of intensity by varying the pulse width (PW) and pulse frequency (PF) of peripheral nerve stimulation. This forced-choice paradigm was then used to determine the just-noticeable difference (JND) for each stimulation parameter, which is defined as how much the stimulation parameter needs to change in order to yield a reliable change in perception. Current experiments aim to expand this prior study to additionally understand the impact of variations in pulse amplitude (PA) on perceived intensity. Preliminary data indicates that discriminability of PA is higher (ie displayed lower JNDs) than that for PF and is similar to that of PW. The findings from this study will be used to design pulse amplitude-based encoding strategies for closed loop prosthetic systems in the future, wherein perceived intensity is mapped to pressure exerted by the prosthetic hand during grasp. Additionally, information gained in this study will enable future research to understand integration of sensation from multiple simultaneous somatosensory percepts.

 

Friday, August 16, 2019
NEC Seminar

9:00 am, Nord 400
Speaker: George Hoeferlin
Advisors: Dr. Jeffrey Capadona
Title: Immunomodulatory Approaches to Mitigating Intracortical Microelectrode Failure

Abstract: Neural interfacing applications to treat neurological disorders and obtain information are becoming more and more prevalent, with new companies and coalitions emerging to provide funding into this area. Intracortical microelectrodes are critical components for these applications. Unfortunately, these electrodes tend to fail over time, usually within months to a few years in clinical trials. One main contributor to this failure is the body's biological response to intracortical microelectrodes. To attempt to mitigate this response and improve the life of these electrodes, three different immunomodulatory approaches were explored. The first utilizes a peptide sequence able to bind to surface molecules on inflammatory cells, preventing their ability to bind to implanted devices. A second approach exploits an enzyme that catalyzes the first and rate-limiting step in a pathway shown to reduce immune response by promoting macrophage differentiation into their anti-inflammatory phenotype. Finally, the last approach is using antibody therapy to target the CD14 receptor. CD14 has been identified to be a strong initiator of the innate immune response through Toll-like receptor (TLR) activation. By using antibodies to block the receptor, we will prevent CD14 from activating TLRs, thus leading to a reduced inflammatory response. Through immunomodulation, each of these approaches aims to reduce the neuroinflammatory response to intracortical microelectrodes, thus prolonging their active life.

Friday, August 9, 2019
NEC Seminar

9:00 am, Nord 400
Speaker: Paul Gloth
Advisors: Prof. Capadona

Abstract: One of the current tools used to probe the brain is the intracortical microelectrode which can record from single neurons or small populations of neurons. Despite the enthusiasm for brain interfacing technologies which utilize the intracortical microelectrode, it is widely understood that microelectrodes exhibit limited long-term viability where recordings typically fail 6 months to 1 year after implantation. This is due to multimodal failure mechanisms including the biological inflammatory response. This chronically inflammaed environment around the implant results in an increase of reactive oxygen species (ROS), leading to oxidative stress around the site. Our lab has previously investigated the use of resveratrol, an antioxidant, to mitigate the oxidative stress and inflammatory response surrounding the implant. In this talk, I will discuss our previous work, delivery method, and current characterization methods for Superoxide Dismutase, an alternative antioxidant.

BME Summer 2019 Seminar Series

Tuesday, August 6, 2019
11:40 a.m.-12:40 p.m.
Wickenden, Room 321
Case Western Reserve University

Deep brain optical imaging in freely behaving animals

Bo Liang, PhD
Research fellow
Neural Engineering Unit, Behavioral Neuroscience Branch, National Institute on Drug Abuse,
Intramural Research Program (NIDA/IRP) National Institutes of Health (NIH)
Bethesda, MD

Abstract: The mammalian brain consists of millions of different types of cells, which anatomically organize as a network with functional activities of multiple time scales from seconds to years. Understanding how coordinated neural activities give rise to behavioral responses requires advanced neural engineering techniques. Optical calcium imaging method has been transforming neuroscience research by enabling large-scale recording of neural activities in a cell-type specific and real-time fashion, yet still face significant challenges in recordings from deep brain regions due to the limited light penetration in the brain tissue. In this talk, I will present our customized miniature fluorescence microscope system allowing longitudinal recording of neural activities from hundreds of neurons in deep brain regions of freely behaving mice. I will describe how miniature microscope imaging system can be leveraged to understand neural coding mechanisms in brain regions such dorsal striatum and medial prefrontal cortex for naturalistic behaviors.

Thursday, August 1, 2019
11:40 a.m.-12:40 p.m.
Wickenden, Room 321

Case Western Reserve University

Sensory information: From neural coding to human experience

Emily Graczyk, PhD
Research Associate, Department of Biomedical Engineering
Case Western Reserve University
Cleveland, Ohio

Abstract: Our senses are responsible for providing us with information about the external world. The somatosensory nervous system provides information about touch and proprioception, wherein receptors in the periphery transduce mechanical stimuli into neural signals, which are sent to the brain via the peripheral nerves. Along this pathway, sensory information is processed and integrated with other neural systems to modulate action, perception, emotion, and other experiences. However, the neural coding of sensory information is complex and the conversion of information into conscious experience is not well understood. With neural-interfacing technology, we can directly interact with sensory information flow by activating sensory neurons through electrical stimulation. Injecting information into the somatosensory pathway with neurotechnology allows us to study sensory information encoding, processing, and perceptual experience in a unique way. Artificial sensation also enables sensory augmentation for the able-bodied, providing additional sensory capabilities beyond the biological senses. Most importantly, electrical stimulation of the somatosensory nervous system can be applied clinically to restore sensation to persons with sensory deficits, including amputation, spinal cord injury, chronic pain, and stroke. We have shown that persons with upper limb loss can interpret and use artificial somatosensory information to improve prosthesis control. In addition, artificial sensation impacts emotional and psychological outcomes. In this talk, I will present recent progress in artificial somatosensation, including efforts to elucidate the neural coding of sensation, demonstrate sensory learning, understand the psychosocial implications of artificial touch, and maximize sensory information transmission using artificial intelligence.


Friday, August 2, 2019
NEC Seminar

9:00 am, Nord 400
Speaker: Nabeel Chowdhury
Advisors: Prof. Tyler
Title: Masked Peripheral Nerve Stimulation Results in Preconscious Motor Activation

Abstract: Most often, research in upper limb prosthetics usage and rehabilitation focuses on the idea of fully restoring a subject's motor ability without much thought to the sensory system's contribution to motor control. The thought is that a perfect replication of the motor control of an able bodied individual will fully restore a prosthesis user's functional ability. An example of perfect motor output with no sensory input exists in those who have a deafferentation of a limb. In these individuals, they excel in the lab doing functional tasks, and yet activities of daily living become almost impossible. Actions like drinking, eating, buttoning a shirt, and writing become nearly impossible because tactile information is needed at a preconscious level to make fine, automatic adjustments to movement. Intuitive sensory information is imperative for intuitive motor control to function. Previous solutions, both noninvasive and invasive, have provided tactile feedback requiring conscious effort to understand leading to useful, but unintuitive feedback. Our group's solution is to send stimuli through nerve cuffs on the peripheral nerves of the amputee's arm so that the signal is naturally directed by physiology to the correct, subcortical areas of the brain before conscious perception occurs. This allows the feedback to be used at a pre-cortical level and therefore more intuitively. In order to test preconscious usage of these stimuli, we backmasked a threshold level stimulus with a medium intensity stimulus and saw subjects' conscious reaction times shift backwards in time compared to when the masked stimulus had not occurred such that the subject is likely reacting to the unfelt, masked stimulus instead of the medium intensity stimulus that they did feel. This implies that the stimulus was used preconsciously to trigger a preplanned motor output. We also compared the reaction times due to stimulated tactile feedback with reaction times due to visual and vibrotactile feedback. Our results show that stimulated reaction times are consistent with tactile reaction times seen with able-bodied individuals and this once again confirms that the artificial tactile information is used similarly if not the same as for an able-bodied individual. These results taken together suggest peripheral nerve stimulation is used intuitively by the brain and could provide feedback resulting in intuitive control of a prosthesis.

 

Friday, July 24, 2019
NEC Seminar

9:00 am, Nord 400
Speaker: Aidan Friederich
Advisors: Dr. Triolo
Title: Characterization of Trunk Muscle Recruitment Properties in Three Dimensions

Abstract: Control of trunk muscles can be significantly compromised after paralysis from spinal cord injury (SCI); which leads to instability when sitting. This is often addressed using wheelchair pads and straps to restrict trunk movement because no method exists to both increase support and stability while also expanding the effective workspace. Neuroprostheses employing functional neuromuscular stimulation (FNS) to activate the trunk muscles together with well-designed feedback control systems can be deployed to replicate dynamic trunk stability and seated balance. Currently, such feedback controllers use simplified linear muscle recruitment curves to relate changes in muscle activation to trunk muscle force output. This can cause destabilizing effects and result in performance loss. Use of nonlinear recruitment curves have been shown to increase performance of knee angle controllers via neural stimulation, however this approach has never been implemented in trunk musculature and three dimensional nonlinear recruitment properties of otherwise paralyzed trunk muscles have yet to been experimentally determined. The purpose of this work is to generate functionally accurate recruitment curves of the main muscles that mediate trunk stability using FNS. A device was designed to hold the trunk in a static position thereby allowing for the transmission of exerted forces during isometric muscle contractions to a six-axis load cell (JR3 100M40). Two participants with spinal cord injuries (C7 ASIA B, T6 ASIA A) were placed in the device and stimulation was applied at increasing pulse widths (PW) from 0µs to 250µs at 10µs steps to individually activate trunk and hip muscles with implanted intramuscular electrodes. The resulting forces in the anterior-posterior, medial-lateral, and inferior-superior directions were captured. The recruitment curves exhibit non-linear behavior and were fit to a Gompertz sigmoid curve. The recruitment curves measured here are expected to result in increased performance of FNS controllers for trunk stability by more accurately relating the PW directly to the force output and providing improved insight to the direction in which each muscle acts.

Friday, June 28, 2019
NEC Seminar

9:00 am, Nord 400
Speaker: Platon Lukyanenko
Advisors: Dustin Tyler
Title: Accelerating a synergy-model-based prosthetic hand controller with an ANN

Abstract: Prosthetic hand control interfaces are typically limited to a 100ms runtime to prevent the perception of lag. As more degrees of freedom are controlled by a prosthetic hand controller, controller runtime may increase. Our group recently developed a user-specific synergy-based model which employs user EMG signals to provide control over 4 degrees of freedom. This model-based controller interprets implanted EMG signals to determine hand speed in a manner which should be more effort-efficient and allows stable control over several months. Model runtime, however, scales exponentially with both the number of EMG signals and the degrees of freedom controlled to prohibitive levels. This constrains the controller's usability in wearable devices for take-home prosthetic systems. One method for handling expensive model runtimes is through function approximators, such as artificial neural networks. Prosthetic hand controllers based on function approximators, however, require large amounts of training data and a separate method for determining hand speed to function. Two trans-radial amputee subjects were implanted with intramuscular electrodes and provided sample movement data. Movement EMG was used to build five user-specific prosthetic hand controllers:
DT: A synergy-model based controller trained on original data
AT: An ANN controller trained on original data with traditional speed determination.
DAT: An ANN trained to mimic DT using original training data.
DATS: An ANN trained to mimic DT using original and simulated EMG data.
DATOS: A DATS controller augmented with roughly a year's worth of online user data.

Results suggest that using an ANN to approximate the model-based controller can improve either runtime or user effort levels without harming controller performance.

 

Friday, June 21, 2019
NEC Seminar

9:00 am, Nord 400
Speaker: Hendrik A Dewald
Advisors: Dr. Kirsch
Title: Functional Impact and Quantification of Peripheral Nerve Blocks

Abstract: Impaired arm and hand function is a major cause of chronic disability among hemiparetic stroke survivors. In particular, the paretic arm and hand are affected by an abnormal flexion synergy where shoulder abduction is accompanied by involuntary elbow, wrist, and finger flexion. This flexion synergy significantly compromises the ability to reach and open the hand for functional tasks, with more severely impaired individuals often unable to open the paretic hand even when the arm is fully supported. A peripheral nerve block would interrupt this maladaptive descending drive, reducing wrist and finger flexion and potentially returning functional use of extensors. The first steps towards evaluating this will focus on observing the impact of complete median and ulnar nerve blocks by local anesthesia in able-bodied individuals, and determining a method by which the resulting motor block can be evaluated at the hand.

NEC Seminar, Friday, June 14
9:00 am, Nord 400
Speaker: Elizabeth Heald
Advisor: Prof. Peckham
Title: Response of below-injury EMG activity to biofeedback training in motor complete SCI

Abstract: Past research has revealed that, even in spinal cord injury (SCI) clinically diagnosed as motor complete, a majority of injuries have some degree of spared descending pathways. For example, epidural spinal cord stimulation has shown some success in promoting functional recovery in chronic, complete SCI; one theory is that this stimulation facilitates the activation of spared spinal pathways. We have previously reported volitional myoelectric activity recorded from the lower extremities of individuals with chronic motor complete SCI; this activity is below the threshold to produce movement but is evident through surface EMG recordings. We hypothesized that decreased or absent sensory feedback may interfere with the ability to reliably activate these spared pathways. Thus, we hypothesized that providing biofeedback of EMG signals to participants with motor complete SCI may improve their ability to activate muscles below the injury level. In this talk, I will present the results of a training protocol implementing visual and audio biofeedback of below-injury EMG signals in 3 participants with chronic motor complete SCI. A discussion of challenges faced during this work, as well as directions for future studies, will also be presented.

Thursday, June 6, 2019
NP Seminar - Industry Round Table

3:00PM, Wolstein Research Building, Room 1413

Speaker: Cameron McIntyre, PhD
Associate Director of Industrial Relations Cleveland FES Center
Professor
Department of Biomedical Engineering Case Western Reserve University
Biomedical Engineer
Louis Stokes Cleveland VA Medical Center

Friday, May 31, 2019
NEC Seminar

9:00 AM, Room Wickenden 105

Speaker: Ryan Reyes
Advisors: Prof. Triolo
Title: Development of a "Muscle First" Control Method for a Motor-Assisted Hybrid Exoskeleton for Walking After Paraplegia

Abstract:
We are developing a "Muscle First" Motor-Assisted Hybrid Neuroprosthesis (MAHNP), which uses implanted neural stimulation to activate the leg muscles to generate the majority of the forces required for walking, while an exoskeletal frame with motors augments or complements voluntary or stimulated muscle activity. Conventional commercially available exoskeletons depend on external motors at the hip and knee joints for all motive power, and are unable to move in response to voluntary or stimulated contractions because their transmissions are typically non-backdrivable. In contrast, the MAHNP features motorized backdrivable joints with low passive resistance which allow the user's muscles to drive the stepping motion. This presentation will discuss the development and verification in simulation of novel low-level control techniques to be implemented at the single joint level to maximize biological power and apply motor assistance as-needed, as well as the development of a higher-level controller to coordinate the movement across all joints for efficient stepping.

Friday, May 17, 2019
NEC Seminar

9:00 AM, Room Wickenden 105 (note location!)

Speaker: Sandra Hnat
Advisors: Drs. Triolo and Audu
Title: Estimating Center of Mass Kinematics During Human Standing Using Inertial Measurement Units

Abstract:
Commercialized powered exoskeletons aim to restore mobility for individuals with spinal cord injuries. These devices are worn in parallel to the user's affected lower-limbs, where electric motors at the joints generate walking, standing, and sitting motions. However, the phase-based impedance controllers used in these devices can only follow predefined trajectories and cannot correct for postural instabilities. Specific control systems are necessary to ensure balance during standing and walking with exoskeletons. Whole-body center of mass (COM) kinematics is an indicator of standing stability. Here, we present a method of calculating COM to be used as global feedback parameters for balance controllers based on simple, easily mounted inertial measurement units (IMUs) suitable for integrating into exoskeletal systems for community use. Our COM Estimation Algorithm is trained using able-bodied experimental data, where test subjects are perturbed during standing to cause measurable changes in their COM position. Test subjects are pulled via linear actuators in the anteroposterior and mediolateral directions (external perturbations). In another set of experiments, the subjects move weighted jars between different locations on a wire rack (internal perturbations). Kinematics inferred from reflective markers and a motion capture system are compared to estimates derived from body-mounted IMUs taped on the subject, which is used to train the algorithm. Preliminary results from one able-bodied subject will be presented and future experiment protocols will be discussed.

 

Friday, May 3, 2019
NEC Seminar

9:00 AM, Room Wickenden 105

Speaker: Kristen Gelenitis
Advisor: Prof. Triolo
Title: Selective Neural Stimulation-Induced Exercise after SCI

Abstract: A majority of the spinal cord injury (SCI) population is confined to a wheelchair. The resulting sedentary lifestyle often leads to muscle atrophy, bone density loss, and cardiovascular disease, as well as decreased independence and low perceived quality of life. Sufficient exercise can largely alleviate or prevent these secondary complications, but achieving adequate exercise volumes is impeded by limited voluntary muscle control. Electrical stimulation-induced exercise methods have been developed to involve the paralyzed musculature and provide a more complete, full body workout. Current stimulation protocols, however, still limit exercise duration due to rapid fatigue of the targeted muscles. We propose the use of duty cycle-reducing stimulation paradigms delivered through selective nerve cuff electrodes to delay muscle fatigue, prolong exercise duration, and maximize cardiovascular benefits. We hypothesize that by sequentially stimulating multiple independent yet synergistic fiber pools, we will allow some fibers to rest and recover while others maintain the desired output, ultimately increasing exercise endurance. Waveform parameters involved in duty-cycle reducing stimulation paradigms have been explored in-depth in an animal model. Major findings are currently being translated to a clinical study involving SCI participants implanted with selective femoral nerve cuffs. Preliminary clinical results from selective neural stimulation-induced cycling exercise trials will be presented, and future investigation directions will be discussed.

 

Friday, April 26, 2019
NEC Seminar

9:00 AM, Nord 400

Speaker: Yang Zheng
Advisor: Dr. Isabelle Deschenes
Title: Dynamic Modulation of Cardiac Sodium Channel Coupling

Abstract: Cardiac arrhythmias and sudden cardiac death (SCD) are worldwide leading causes of morbidity and mortality, accounting for 15-20% of all deaths. Mutations in the gene encoding Nav1.5, SCN5A, have been linked to a variety of arrhythmogenic diseases such as Long QT syndrome type III (LQT3) and Brugada syndrome (BrS) that can cause SCD. However, the mechanism of the channelopathy is not fully understood. The Nav1.5, or cardiac voltage-gated sodium channel, is a membrane protein found in cardiomyocytes responsible for the rapid upstroke of the action potential (AP) and thus is central for the genesis and development of cardiac arrhythmic diseases. Our lab has previously found that Nav1.5 α-subunits can assemble as dimers, and this physical coupling can lead to functional or biophysical coupling. The biophysical coupling of Nav1.5 could profoundly change the current knowledge of cardiac sodium channel biophysics. More importantly, we found that the coupling between the wildtype sodium channel and the diseased mutant can impair the function of the wildtype sodium channel. This finding suggests that the biophysical coupling plays an important role in cardiac arrhythmic disease phenotypes and could be a potential therapeutic target. In order to study the therapeutic potential of manipulating Nav1.5 biophysical coupling, we first need to study the regulation of the biophysical coupling. In a recent study, we identified the involvement of a Nav1.5 partner protein, 14-3-3, in the biophysical coupling. The binding activity of 14-3-3 is typically dependent on the phosphorylation of its target protein. Therefore, we speculate that regulating the biophysical coupling could be achieved by regulating phosphorylation of the Nav1.5 motif that controls 14-3-3 binding activity. PKA has been gaining great attention in the cardiovascular field due to its engagement in multiple pathological settings, and it has been shown to phosphorylate Nav1.5. Also, we have preliminary data suggesting that PKA can modulate the binding activity between 14-3-3 and Nav1.5. Hence we posit that the 'PKA - 14-3-3 - Nav1.5-biophyscial-coupling' pathway is essential in identifying therapeutic targets to manipulate the biophysical coupling between the wildtype Nav1.5 and mutants. We therefore hypothesize that biophysical coupling of Nav1.5 can be dynamically modulated by É¿-adrenergic stimulation/PKA phosphorylation, and has implication for cardiac sodium currents and action potentials under both normal and pathogenic conditions.

Friday, April 5, 2019
NEC Seminar

9:00 AM, Nord 400

Speaker: Tyler Johnson
Advisor: Prof. D. Taylor
Title: Improving Neural Control of an FES Arm Model

Abstract: We are working on a method of controlling upper limb reaching with functional electrical stimulation (FES) where neural signals are put directly in control of muscle stimulation levels. Our model decodes cortical spiking activity into muscle activations and these resulting activations are sent to a Dynamic Arm Simulator (R. Kirsch lab) which realistically simulates the movements of a paralyzed human arm activated via FES. Subjects are then able to control this arm model by thinking about moving their own limbs while receiving visual feedback in the form of a cursor moving on a screen corresponding to the fingertip location of the model arm. The efficacy of this system is largely dependent upon the appropriateness of the transfer function that maps neural signals to muscle activations. To generate this transfer function, we are first building a lookup table of empirical data on the arm's response to stimulation and then using a pseudoinverse method to estimate muscle activations from the lookup table based on assumed intended movements. This process gives us a rough estimate of appropriate muscle activation to regress with neural signals to build the final transfer function. This process has previously been shown to work well but also inherently leads to a slight skewing of the resultant movement compared to the intended movement. This research seeks to better understand this skewing and develop methods to alleviate it for better FES control requiring less adaptation by the user.

 

Friday, March 29, 2019
NEC Seminar

9:00 AM, Nord 400

Speaker: Youjoung Kim

Advisor: Prof. Capadona
Title: Localized Resveratrol Delivery Improves Recording Quality from Intracortical Microelectrodes

Abstract: Intracortical Microelectrodes (IMEs) are valuable tools in neuroscience and neurology that allow recording of neural activity. Unfortunately, signal quality from IMEs decreases over time, partly due to biological failure mechanisms. The inflammatory response elicited by the implant of the electrode, leads to the activation of glial cells, release of cytokines and other pro-inflammatory molecules, and encapsulation of the electrode. The inflammatory environment around the implant results in an increase of reactive oxygen species (ROS), leading to oxidative stress around the implant site. Increasing ROS levels may lead to neuronal cell death, increased inflammation, and the corrosion and delamination of the microelectrode surface. Our lab has previously investigated the use of resveratrol, an antioxidant, to mitigate the oxidative stress and inflammatory response surrounding the implant. Abdominal adhesions resulting from chronic repeated intraperitoneal delivery (IP) of resveratrol led us to investigate modes of localized drug delivery. The goal of this study is to examine the effects intracerebroventricular (ICV) delivery of resveratrol has on electrophysiological recording quality and stability, as well as resulting neuroinflammation and oxidative stress. We hypothesize that ICV resveratrol delivery will mitigate oxidative stress around the electrode, ultimately leading to prolonged recording quality and neuron health, without the side effects seen with IP delivery. Sixteen Sprague Dawley rats were implanted with a silicon, single shank, 16 channel intracortical microelectrode in the motor cortex, with eight animals in each group. Resveratrol group animals were also implanted with an Alzet Osmotic Pump and brain infusion kit, loaded with a solution of 500mM pure trans-resveratrol powder dissolved in Poly(ethylene glycol) (PEG200). Electrophysiology and end-point histology were evaluated and found that the experimental group showed significant (p<0.05) improvement in recording performance (units per channel and percentage of channels recording single units). However, end-point histology showed an insignificant difference between the control and resveratrol groups for activated astrocytes, activated microglia, neuronal density, blood brain, and permeability. Results for oxidative stress markers 4-hydroxynonenal (oxidized lipids) and nitrotyrosine (oxidized proteins) will be discussed further in the presentation.

 

Friday, March 22, 2019
NP Seminar

8:30 AM, Wolstein Research Building, Room 1413

Speaker: Kenneth Baker, PhD
Investigator
Cleveland FES Center
Adjunct Assistant Professor, Molecular Medicine
Cleveland Clinic Lerner College of Medicine
Case Western Reserve University

Title: Deep Brain Stimulation: Developing, Optimizing, and Understanding Therapeutic Strategies in Stroke and Parkinson's Disease

Kenneth Baker, PhD has over twenty years of experience in deep brain stimulation (DBS), both clinically and in the laboratory. His research interests largely involve the therapeutic application and mechanisms of neurostimulation-based approaches to neurologic and psychiatric disease, with a particular focus on the use of DBS for the treatment of Parkinson's disease, stroke, and traumatic brain injury. In his presentation, Dr. Baker will provide an overview of the preclinical and clinical research studies currently underway in his laboratory.

Current NIH-supported projects include 1) developing and testing novel DBS paradigms to enhance therapeutic outcomes in Parkinson's disease, 2) optimizing deep cerebellar stimulation to enhance chronic, post-stroke rehabilitation and 3) an on-going, phase I clinical trial of cerebellar dentate nucleus DBS in human stroke patients.

 

Friday, March 8, 2019
NEC Seminar

9:00 AM, Nord 400

Presenter: Joseph Marmerstein
Ph.D. Candidate, Biomedical Engineering

Advisor: Prof. Durand
Title: Chronic Recording of Rat Vagal Tone with Carbon Nanotube Yarn Electrodes

Abstract:
The study of small peripheral nerves such as those in the autonomic nervous system holds great promise for the detection and treatment of a variety of pathologies. In particular, the vagus nerve, which is a highway of autonomic activity, has been receiving increased attention due to it's interaction with nearly every internal organ in the body. Additionally, vagal tone is a clinical measure that is generally correlated with patient outcomes in many diseases, leading to interest in the vagus nerve as a therapeutic target for everything from epilepsy to autoimmune disorders. However, vagal tone has never been directly measured and is only correlated to clinical factors such as heart rate variability. Dr. Durand's group has developed a novel way for interfacing with the vagus, via carbon nanotube (CNT) yarn microelectrodes. A possible direct measure of vagal tone is explored, using ECG monitoring to average vagal signals during periods of heart rate increase and decrease. Vagal activity is increased during periods of heart rate decrease, mirroring known behavior of cardiac vagal efferent fibers.

Note: There will not be a seminar on March 15 during Spring Break.

 

Friday, March 1, 2019
NEC Seminar

9:00 AM, Nord 400

Presenter: Kelsey Bower
NIH Predoctoral Fellow, McIntyre Lab

Title: Deep brain stimulation of afferent axon terminals: the effect of myelination

Abstract:
Numerous cell types exist in the region of the subthalamic nucleus (STN), including fibers of passage, local STN cells, and terminating STN afferents. Histological studies in the rat have identified "hyperdirect" axons which originate in motor cortex and project terminating collaterals to the STN. Recent optogenetic studies, capable of dissecting the neural circuitry and selectively stimulating these distinct neural elements, suggest that cortico-STN afferents may play an important role in the therapeutic effects of DBS. The goal of this study is to identify the behavior of terminating afferents in response to DBS using a computational modeling approach.

A computational model of a branched axon terminal was generated, with a structure that mimicked a hyperdirect axon. The axons were placed within the internal capsule of a FEM of the human head in order to best represent the location of the hyperdirect pathway. Activation thresholds of terminating fibers were compared to that of diameter-matched fibers of passage to identify the effects of termination. Myelinated terminating axons exhibited lower activation thresholds than diameter-matched fibers of passage, however unmyelinated terminating axons showed the opposite trend. These results show that the degree of myelination can affect the relative excitability of these structures.

Friday, February 22, 2019
NEC Seminar

9:00 AM, Nord 400

Speaker: Ivana Cuberovic
Advisor: Prof. Tyler

Title: The perceptual and psychological experience of a sensory feedback prosthesis over two months of home use

Abstract: A prosthesis can replace the functional capabilities of a lost hand and modify the user's perception of their body. Prior studies have shown that sensory feedback provided through electrical stimulation or targeted muscle reinnervation promotes prosthesis embodiment. However, the time course of this process has not been elucidated. Extended usage of a sensory feedback prosthesis may lead to progressive changes in sensory or bodily perception, as the user learns to integrate the artificial sensory information into their preconscious sensorimotor processes and conscious body perceptions and attitudes. In this case study, we examined how passive learning over two months of home use of a sensory-enabled prosthetic hand influences sensory perception, functional performance, and psychosocial outcomes. Sensory feedback was provided to a participant with unilateral upper limb loss via electrical stimulation through implanted neural interfaces, and the sensations were controlled by three pressure sensors and one joint angle sensor embedded in a myoelectric prosthetic hand.

We examined the impact of extended daily usage of the sensory-enabled prosthesis on the evoked sensory percepts by tracking perceived sensation intensity, quality, and location at system donning and doffing each day. Across days of home use, ratings for negative quality descriptors, such as "unpleasant" or "sharp", did not vary significantly from 0 for any. Conversely, ratings for descriptors that were congruent with sensor usage, including "natural", "pressure", "contact", and "vibrating", increased over time for some channels. Reported sensory locations also changed throughout the study. For two of the tactile channels, the location moved towards the sensor location over time. At earlier time points, this the sensation location shifted throughout a day of usage towards the sensor location. At later time points, the congruent sensory location was retained, overlapping the sensor location immediately upon donning.

We assess the impact of passive learning on performance of functional tasks. As previously reported, the subject's ability to determine the size or compliance of an object improved significantly when he had sensory feedback as compared to when he did not. While both the subject's performance and confidence increased with time, these trends were not significant.

Finally, we investigated the psychosocial experience of prosthesis use through daily surveys. Psychosocial survey scores of self-efficacy, prosthesis embodiment, social touch with the prosthesis, and perceived prosthesis efficiency improved significantly within the first month. Survey scores of perceived disability also showed significant improvement, albeit over a longer time course. Our findings suggest that passive learning modulates the perceptual and psychological experience of a sensory-enabled prosthesis over time.

 

Friday, February 8, 2019 CANCELED
NP Seminar

10 AM, Wolstein Research Building, Room 1413

Speaker: Adam Gazzaley MD., PhD
Professor in Neurology, Physiology and Psychiatry at University of California, San Francisco and the Founder & Executive Director of Neuroscape

Title: Technology meets Neuroscience - A Vision of the Future of Brain Optimization

A fundamental challenge of modern society is the development of effective approaches to enhance brain function and cognition in both the healthy and impaired. For the healthy, this should be a core mission of our educational system and for the cognitively impaired this is the primary goal of our medical system. Unfortunately, neither of these systems have effectively met this challenge. I will describe a novel approach developed at UCSF's Neuroscape and advanced by Akili Interactive that uses custom-designed video games to achieve meaningful and sustainable cognitive enhancement via personalized closed-loop systems (Nature 2013; Neuron 4014). I will also share with you the next stage of our research program, which integrates our video games with the latest technological innovations in software (e.g., brain computer interface algorithms, GPU computing, cloud-based analytics) and hardware (e.g., virtual reality, mobile EEG, motion capture, physiological recording devices (watches), transcranial brain stimulation) to further enhance our brain's information processing systems with the ultimate aim of improving quality of life.

 

Friday, February 1, 2019
NEC Seminar

9:00 AM, NORD 400

Speaker: Nicholas Couturier
Advisor: Prof. Durand

Abstract
Problem: Epilepsy is one of the most pervasive neurological disorders, affecting approximately 1% of the world's population. Each year it is estimated that there are between 16 and 51 new patients diagnosed with an epilepsy disorder per 100,000 people. Unfortunately, around 20% of these patients do not respond to antiepileptic medication. The most common alternative to medication is surgical resection; however, most patients are not eligible for resection due to an inability to identify a well‐defined epileptogenic region that is not colocalized with any eloquent cortex. Furthermore, of the patients who are eligible for surgical resection, only about half gain freedom from seizures. More recently, several deep brain stimulation technologies have been developed around the unmet need for seizure suppression in patients for whom medication and surgery are not viable options. These FDA approved DBS therapies rely on high-frequency (HFS) (>100Hz) grey matter stimulation of either the focus itself or the anterior nucleus of the thalamus. The results of these methods have been mixed with about 50% of patients obtaining a greater than 50% reduction in seizure frequency.

Methods: 4-Aminopyridine (4-AP) was injected in the motor cortex and recording electrodes were placed in the contralateral cortex and hippocampus to monitor activity. Bipolar stimulating electrodes were placed in the medial aspect of the corpus callosum. Local field potentials were recorded 1 hour before, during, and after stimulation to determine the effect of stimulation on seizure duration.

Results: Our latest publication demonstrates a 90% suppression of cortical seizures in this acute model of cortical epilepsy. Seizures were suppressed in the hippocampus as well as the cortex only when stimulation was applied at low frequencies (10-20Hz).

Relevance: Our lab has developed a novel technique for suppressing seizures with DBS. White matter low frequency stimulation (LFS) (≤20Hz) provides a means of lowering the excitability of a large portion of the brain simultaneously. We are currently performing direct comparisons between currently available DBS methods and CCLFS in a similar acute model of focal cortical epilepsy. Selective stimulation of this large fiber tract may provide a powerful new tool in treating cortical epilepsies.

 

Friday, January 25, 2019
NP Seminar

8:30 AM, Wolstein Room 1413

Speaker: Christos Davatzikos, PhD
Wallace T. Miller Sr., Professor of Radiology
University of Pennsylvania School of Medicine

Title: Machine Learning in Neuroimaging: Applications to Clinical Neuroscience and Neurooncology

 

Friday, January 18, 2019
NEC Seminar

9:00 AM, Nord 400

Speaker: Breanne Christie
Advisors: Dr. Triolo and Dr. Tyler
Title: Preliminary results on a skilled walking task after restoring lower-limb sensory feedback

Abstract
Plantar sensory feedback plays an important role during balance [Perry 2000, Billot 2013] and gait [Hohne 2012]. If it is eliminated, people can typically compensate using their remaining musculoskeletal, visual, cognitive, and vestibular resources [Geurts 1992]. Few functional tasks can directly isolate and evaluate the role of plantar cutaneous feedback in one foot at a time. One such test, called the "horizontal ladder rung walking test" has identified minor sensorimotor impairments in rats [Metz 2002], cats [Bouyer and Rossignol 2003], and monkeys [Higurashi 2009]. During this test, a ladder was laid horizontally on the ground and the animal was trained to walk across without slipping and touching the ground. In our study, two unilateral trans-tibial amputees performed this skilled walking task. In half of the trials, somatosensory percepts were evoked by electrically stimulating residual lower-limb nerves via cuff electrodes. Stimulation parameters varied as a function of plantar pressure, as measured by force-sensing insoles placed underneath the prostheses. Somatosensory percepts were evoked in the amputee's missing forefoot, midfoot, and/or rearfoot to signify which the region of the prosthetic foot that was in contact with a ladder rung. Using video recordings, we measured foot placement accuracy, the number of searching taps per ladder rung, and trial time. Preliminary results show that in one out of two participants, searching strategy changed and foot placement was more accurate during trials with sensory feedback.

Friday, January 11, 2019
NEC Seminar

9:00 AM, Nord 400

Speaker: Natalie Cole
Advisor: Prof. Bolu Ajiboye
Title: Time-invariant Muscle Synergies from Dynamic Hand Function

Abstract
The present study investigates the use of low-dimensional muscle coordination patterns (i.e. synergies) as a framework for creating high-dimensional muscle activation patterns associated with complex hand movements. The ultimate goal of this work is to develop muscle synergy based command interfaces for Functional Electrical Stimulation neuroprostheses that restore dexterous grasp function to persons with mid-cervical level (C5/C6) spinal cord injury. Muscle synergies extracted from a limited set of hand postures have been successfully used to reconstruct the muscle activation patterns required to reproduce a wide range of new hand postures. However, it is unclear whether muscle synergy modules can be used to reproduce the time-varying muscle activation patterns observed during functional hand movements involving object interactions. Additionally, with the end goal of neuroprosthetic control, it must be determined whether as few as three synergies can reproduce time-varying muscle activation. This work examines whether a low-dimensional set of synergies can be extracted from and recreate muscle activation patterns observed during time-varying (non-isometric) hand function as well as or better than static synergies derived from (isometric) hand postures.

2018

Friday, December 7, 2018
NP Seminar

8:30 AM, Wolstein Research Building, Room 1413

Speaker: Mark Griswold, PhD
Professor, Dept. of Radiology, School of Medicine

 

Friday, November 30, 2018
NEC Seminar

9:00 AM, Nord 204

Speaker: Cale Crowder
Advisor: Bob Kirsch, PhD
Title: Towards a Universal Brain-Computer Interface Decoder

Abstract
People with AIS-A spinal cord injuries at levels C1-C4 experience paralysis of all four limbs. In order to alleviate paralysis of the upper extremity, our research group uses an intracortical brain-computer interface to control a functional electrical stimulation system. Our brain-computer interface estimates how participants intend to move using an algorithm called a "decoder." However, this decoder must be recalibrated daily, and it must be retrained for different study participants. During this seminar, we will discuss methods for improving decoders to make them stable across days, and potentially across participants.

 

Friday, November 16, 2018
NP Seminar

8:30 am Wolstein Research Building, Room 1413
Speaker: Nanthia Suthana, PhD
Assistant Professor-in-Residence
David Geffen School of Medicine at UCLA
Department of Neurosurgery
Title: Brain Implants, Virtual Reality, and Treatment of Neuropsychiatric Disorders

Abstract
Progress in neuroprosthetics and virtual reality technology provide unprecedented opportunities to discover the neural substrates of human cognition, specifically to examine and modulate deep brain activity during real world behaviors such as spatial navigation and episodic memory. In this talk Dr. Suthana will discuss current findings and ongoing projects using recordings deep from within the brain in freely moving humans combined with full body motion capture and virtual reality methodologies to understand functions such as spatial navigation and episodic learning and memory. She will also discuss ongoing projects underway that utilize deep brain stimulation and recordings in ways that are relevant for characterizing and treating neuropsychiatric disorders such as post-traumatic stress disorder.

 

Friday, November 9, 2018
NEC Seminar

9:00 AM, Nord 204
Speaker: Rajat Shivacharan
Advisor: Prof. Durand
Title: Self-propagating, non-synaptic hippocampal waves travel by electric field coupling

Abstract
It is well documented that synapses play a significant role in the transmission of information between neurons in the brain. However, in the absence of synaptic transmission, neural activity has been observed to continue to propagate. Experiments conducted in our lab have shown that propagation of epileptiform behavior in rodent hippocampi propagates at a speed of ~0.1 m/s. This observed activity propagates independently of synaptic transmission and gap junctions and is outside the range of ionic diffusion and axonal conduction speeds. Computer simulations of pyramidal neurons indicate that ephaptic coupling, or electric field coupling, could be responsible for this propagation of neural activity in pathological conditions such as epilepsy. Recent studies suggest electric fields can activate neighboring neurons, thereby generating a self-propagating wave. However, there is no experimental data suggesting ephaptic coupling is necessary and sufficient for spontaneous, self-regenerating propagation of neural activity. Using in vitro and in vivo electrophysiology in combination with imaging of trans-membrane voltages using genetically encoded voltage indicators, we test the hypothesis that ephaptic coupling is a critical mechanism for self-propagating, non-synaptic neural propagation.

 

Friday November 2, 2018
NEC seminar
9:00 AM, Nord 204
Speaker: Sydney Song
Advisor: Prof. Capadona
Title: Targeting ROS in Order to Prolong the Lifespan of Intracortically Implanted Microelectrodes

Abstract
Intracortical microelectrodes implanted in the brain can record action potentials from individual neurons. The recorded action potentials can be used both for basic research and for clinical rehabilitation purposes. Unfortunately, the implanted devices fail rather quickly, often within months to years. This is due to the damage the device causes the brain, and due to the brain's rejection of the implanted foreign objects. One mechanism of failure we focus on is neurolinflammation and subsequent neurodegeneration driven by the activation of microglia cells, which are resident macrophages of the brain. Microglia cells becomes activated when they sense potential insults to the brain. Once activated, they secrete a number of inflammatory mediators and toxic substances in an attempt to eliminate potential threats. One such factor secreted is Reactive Oxygen Species, which damages DNA, proteins, and cell membrane, killing or severely injuring cells surrounding the microelectrodes. These reactive oxygen species also lead to material damage of the electrode such as corrosion. Our goal is to coat the electrodes with potential antioxidant to diminish the activity of ROS, lessening the injury ROS causes surrounding cells and electrodes. We hypothesize that our approaches will ultimately prolong recording lifespan of the microelectrodes, so that they can become useful both in basic research and clinical application.

 

Friday October 26, 2018
NEC Seminar

9:00 AM, Nord 204
Speaker: Christopher Delianides
Advisor: Dr. Triolo
Title: Balanced Human Ankle Motion Using Implanted Tibial and Fibular Nerve Cuffs

Abstract
Selective stimulation of peripheral nerve fascicles via implanted multi-contact Nerve Cuff Electrodes (NCEs) has been shown to help restore motor functions such as standing and stepping. To achieve a functional and natural gait pattern, net moments generated through stimulation should be sufficiently strong along the axis of motion, while minimal and balanced along minor axes. Here, we attempt to achieve this balanced motion at the ankle joint for a Spinal Cord Injury (SCI) subject with bilaterally implanted 8-contact NCEs on the tibial and fibular nerves. Using combinations of individual contacts activating independent motor unit populations, our goal is to determine to what degree we can achieve balanced motion, and secondly, to what degree this depends on the order in which contacts are activated. As an indicator of the long term affects of NCEs on subject condition, we additionally tracked clinical measures of neurophysiologic health over a period of 6 months.

Our results indicate that balanced plantar flexion was more achievable for the left leg than for the right, with balanced dorsiflexion proving difficult to achieve for either leg. Part of this may stem from observed changes in each contact's moment output between initial collection and combination testing, as well as subject fatigue and invoked reflexive activity. Variation between the three stimulation paradigms was low across all trials, providing evidence against the combinatorial moment being path-dependent.Clinical data supports a preservation of nerve health over the testing period, with compound motor and sensory potentials remaining stable.

 

Friday October 19, 2018
NEC Seminar

9:00 AM, Nord 204
Speaker: Chia-Chu Chiang, Ph.D.
Advisor: Prof. Dominique Durand
Title: Slow oscillations during sleep propagate by ephaptic coupling

Abstract
Slow oscillations are a standard feature observed in the cortex and the hippocampus during slow wave sleep. Slow oscillations are characterized by low-frequency periodic activity (<1Hz) and are thought to be related to memory consolidation. These waves are assumed to be a reflection of the underlying neural activity, but it is not known if they can, by themselves, be self-sustained and propagate. Previous studies have shown that slow periodic activity can be reproduced in the in-vitro preparation to mimic in-vivo slow oscillations. Slow periodic activity can propagate with speeds around 0.1 m/s and be modulated by weak electric fields. In the present study, we show that slow periodic activity in the longitudinal hippocampal slice is a self-regenerating wave which can propagate with and without chemical or electrical synaptic transmission at the same speeds. We also show that applying local extracellular electric fields can modulate or even block the propagation of this wave both in in-silico and in-vitro models. Our results support the notion that ephaptic coupling plays a significant role in the propagation of the slow hippocampal periodic activity. Moreover, these results indicate that a neural network can give rise to sustained self-propagating waves by ephaptic coupling, suggesting a novel propagation mechanism for neural activity under normal physiological conditions.

 

Friday, October 12, 2018
NP Seminar
8:30am, DeGrace Hall Room 312
Speaker: Cameron McIntyre
Investigator, Cleveland FES Center
Title: Connectomic Deep Brain Stimulation

Abstract
Deep brain stimulation (DBS) has been a successful clinical therapy, primarily used to treat movement disorders, for over 30 years. In attempts to expand the clinical indications for DBS, as well as improve outcomes from the therapy, a major focus of present day DBS research is in the development of patient-specific MRI-based surgical targeting strategies for electrode placement. This work is leveraging advances in both anatomical and diffusion-weighted imaging to provide patient-specific connectomic maps of the brain networks being modulated by DBS, which are helping to elucidate optimal stimulation strategies for different disorders. This talk will highlight how these new computational imaging tools are being created and used to improve the clinical application of DBS for a wide range of indications, including depression and Parkinson's disease.

 

Friday October 5, 2018
NEC seminar

Nord 204, 9:00 AM
Speaker: Anisha Rastogi
Research Advisor: Dr. Bolu Ajiboye
Title: Evaluating the effects of volitional state on force representation in motor cortex of intracortical BCI users with chronic tetraplegia

Background
Intracortical brain computer interfaces (iBCIs) have the potential to restore hand grasping in individuals with tetraplegia. While most human-operated iBCIs have utilized only kinematic information from motor cortex, natural grasping and object interaction also requires the use of force-related information. Previous fMRI literature suggests that despite deafferentation-induced cortical reorganization, force-related neural activity may be preserved in individuals with tetraplegia, and that neural representation of force may be affected by volitional state, i.e., whether motor activity is observed, imagined, or attempted (Cramer 2005). Here, we characterize the extent of neural modulation during observed, imagined, and attempted hand grasping forces at the resolution of action potentials in persons with chronic tetraplegia. We also characterize how volitional state affects our ability to discriminate intended force outputs from neural activity. Methods: Participants of the BrainGate2 Clinical Trial were asked to observe, imagine, and attempt to produce three discrete force levels (light, medium, hard) with the dominant upper limb, using a power grasp and a pincer grasp. During the task, full broadband neural recordings were obtained from two, 96-channel microelectrode arrays (Blackrock Microsystems, Salt Lake City, UT) in the dominant motor cortex. From each channel, we extracted two time-varying neural features (spike firing rates and high frequency spike power). We applied 2-way ANOVA to each feature to determine tuning to force and volitional state. To elucidate the extent of force representation at the level of the neural population, we applied demixed principal component analysis (dPCA) to the extracted neural features (Kobak 2016). The resulting dPCs were used to offline-discriminate discrete forces produced during each volitional state. Results and Conclusions: In multiple participants, we found that force-related activity was preserved in motor cortex, both at the single-feature level and at the population level. Most force-tuned features exhibited mixed selectivity to force and volitional state; i.e., they were either independently tuned to both factors, or they exhibited a statistically significant interaction between force and volitional state (2-way ANOVA, p<=0.01). Intended forces were discriminated significantly above chance at the resolution of 20-ms time windows, and were best discriminated during attempted force production. These results support the feasibility of incorporating real-time force control into closed-loop iBCI systems intended for human use.

 

Friday September 28, 2018
NEC seminar

Nord 204, 9:00 AM
Speaker: Nabeel Chowdhury
Research Advisor: Dr. Dustin Tyler
Title: Reduced Simple Reaction Times to Peripheral Nerve Stimulation May Indicate Preconscious Processing of Tactile Feedback

Abstract
The majority of prosthetic users must rely on using their vision as their only form of feedback when performing daily tasks and restricts the user to focusing on individual actions. Haptic feedback could overcome this limitation and allow users to multitask by reducing some of the mental effort of the task. Despite the advent of various haptic feedback mechanisms though, they are not utilized very effectively. Vibrotactile feedback, the most common form of haptic feedback, has been shown to be only marginally better than vision alone. Cortical stimulation of the somatosensory cortex was meant to eliminate the transmission delay from the fingertip to the brain to result in faster utilization of the feedback, yet it results in a significant processing delay before the feedback can be utilized. Both of these feedback methods skip the normal transmission pathway of tactile feedback, which suggests that there is some inherent benefit to receiving feedback directly through the peripheral nerve track of the amputated hand. In this talk, I use the simple reaction time to a task as a metric for the processing delay to feedback and I compare the results of subjects who receive peripheral nerve stimulation to reported simple reaction times to vibrotactile stimulation. Preliminary results of the study show that subjects who receive peripheral nerve stimulation can react to tactile feedback much faster than individuals who received vibrotactile feedback. This suggests that peripheral nerve stimulation is preprocessed at a preconscious level and can result in a more efficient usage when compared to vibrotactile stimulation.

Friday September 14, 2018
NEC seminar

NOTE LOCATION: Nord 240, 9:00 AM
Speaker: Hillary Bedell
Advisor: Prof. Capadona
Title: A review of active anti-inflammatory approaches to reduce the biological response to intracortical microelectrodes

Abstract
One of the current tools used to probe the brain is the intracortical microelectrode which can record from single neurons or small populations of neurons. Despite the enthusiasm for brain interfacing technologies which utilize the intracortical microelectrode, it is widely understood that microelectrodes exhibit limited long-term viability where recordings typically fail 6 months to 1 year after implantation. This is due to multimodal failure mechanisms including the biological response. There are many strategies undertaken by research groups to reduce this biological response to intracortical microelectrodes. This talk will outline different active anti-inflammatory approaches being explored to reduce the inflammatory response to these devices. The talk will end detailing my current work—an exploratory study to find key molecular players in neuroinflammation in response to intracortical microelectrodes.

 

Friday August 10, 2018
NEC seminar

Nord 400, 9:00 AM
Speaker: Hendrik Dewald
Advisor: Prof. Kirsch
Title: Impact of Peripheral Nerve Block on Flexion Synergy Expression at the Wrist and Hand in Stroke

Abstract
Stroke is a leading cause of serious long-term disability, affecting about 3% of males and 2% of females nationwide. Following a hemiparetic stroke, the majority of individuals suffer a loss of independent joint control through the consistent expression of abnormal limb synergies. These synergies significantly impair paretic limb reach distance and hand use, with activation of shoulder abductor muscles becoming intrinsically coupled with flexion at the elbow, wrist, and hand. More severely impaired individuals may not be able to open the hand, even with the weight of the paretic arm supported.

Recent research has shown that these synergies originate in the central nervous system and that there is no change in muscle passive stiffness properties at the fingers. Rather, the ongoing and continuous activation of flexors due to the abnormal drive is at play. The studies proposed here intend to circumvent this abnormal command from the central nervous system through the application of a peripheral nerve block, potentially preventing the abnormal activation of wrist and finger flexors.

Firstly, we will characterize the impact of ulnar and ulnar/median nerve block by lidocaine on hand opening and synergy-induced unintentional grasp forces in stroke patients. Secondly, we will observe the lidocaine block's effect on prediction of intent by electromyographic signals and efficacy of surface-based functional electrical stimulation assistive devices. We hypothesize that blocking these nerves will reduce abnormal wrist and finger flexor hypertonicity significantly and improve control of, and intent-derivation for, assistive approaches.

Lastly, we will investigate the possible future application of more clinically relevant high-frequency alternating current nerve conduction block techniques through observation of a surface-based tibial nerve block in able-bodied individuals. We hypothesize that the onset response of these techniques will not cause significant discomfort to subjects.

Should this exploratory study reveal sufficient efficacy of nerve block in the relief of flexor hypertonicity in stroke and minimal discomfort from the onset response, new opportunities in stroke rehabilitation interventions become possible. This includes the use of implanted nerve cuff electrodes to implement partial or complete nerve block, thus making the use of FES to power hand function viable.

 

Friday July 27, 2018
NEC seminar

Nord 400, 9:00 AM
Speaker: Alistair McEwan
Ainsworth Chair of Technology and Innovation
The University of Sydney
Cerebral Palsy Alliance
Biomedical Devices and Instrumentation Coordinator, BMET
Institute Faculty of Engineering and Information Technologies
Title: Neural interfaces for cerebral palsy

Abstract
From an engineering point of view I will outline the latest understanding and needs in Cerebral Palsy, the most common childhood disability with no cure and delayed diagnosis. We will also describe opportunities for control of muscle groups, spasticity and sensory perception including pain. While people with spinal cord injury have been the target of motor prosthesis to date there are additional challenges to explore in cerebral palsy such as developmental differences and viable afferent pathways that may convey pain and other sensory signals. We see opportunities in both central and peripheral stimulation and monitoring. Our group has a background in impedance recordings which might be used as a novel monitoring tool or to optimise stimulation patterns. We also use electrical tissue properties to better identify pathological tissue and guide electrical stimulation, electroporation and heating in the management of electrical signalling pathways.

 

Friday July 20, 2018
NEC seminar

Nord 400, 9:00 AM
Speaker: Elizabeth Heald
Advisors: Prof. Peckham
Title: Utilizing Muscle Activity from Below the Spinal Cord Injury Level for Neuroprosthetic Control

Abstract
As neuroprosthetic technology improves, there is an increased need for command signals to control the additional functionality that can be provided to users. In a previous study, EMG recordings from the lower extremity of subjects with motor complete SCI indicated that the majority showed some degree of volitional activity in at least one muscle, even though no joint movement was observed. This is in agreement with a growing body of work indicating that even in motor complete SCI, most cases still demonstrate some axonal sparing across the lesion. If descending motor commands can be volitionally and reliably produced, the EMG generated may be used as a command signal, even if it is too small to produce discernable joint movement. Utilizing these signals as command inputs could offer an innovative solution to the problem of too few control signals in current neural prosthesis systems. In this talk, results will be presented from an experiment demonstrating feasibility of using below-injury myoelectric activity as a command signal for an upper extremity grasp neuroprosthesis. In addition, I will discuss a biofeedback training paradigm which is being implemented in an ongoing study with the goal of improving the quality of weak below-injury muscle signals to that which would be useful for neuroprosthetic control.

Friday July 14, 2018
NEC seminar

Nord 400, 9:00 AM
Speaker: Dr. Brooke Odle
Advisors: Drs. Ron Triolo and Musa Audu
Title: Estimating the Interaction Forces of the Upper Extremities and Support Devices

Abstract
Knowledge of upper extremity (UE) effort exerted on a support device under real world conditions is important for understanding the voluntary contributions to the postural shifts by persons with motor or sensory disorders to complete many activities of daily living while standing. This information is critical to further advance the development of neural stimulation control systems for enhancing balance during standing and walking after paralysis. In this talk, experimental pilot studies that resulted in the development and evaluation of linear models that accurately account for intact volitional control exerted by the UEs on a support device will be presented and discussed.

Friday June 29
NEC Seminar

9:00 AM, Nord 400
Speaker: Jessica De Abreu
Advisor: Prof. Kirsch
Title: Virtual reality models for studying object interaction effects in BCI-controlled reaching tasks

Abstract
Recent studies using brain computer interfaces (BCI) demonstrated unexpected changes in neural activity when participants attempted to interact with objects. In order to restore motor function to people with paralysis, it is important to characterize changes in neural activity that may occur during interaction with objects and to elucidate the underlying mechanisms driving these changes. In this talk we will introduce virtual reality (VR) models as tools for investigating how neural activity changes during tasks that require interaction with objects. We will provide a brief tutorial about how to implement realistic virtual reality simulations. The audience should expect to leave with a basic understanding of how VR models implement physics and how current VR software supports and limits VR model usage in neuroscience and neuroengineering.

Friday, June 22, 2108
NP Seminar
Noon, BRB 105
Speaker: Peter Kirkwood,PhD
Emeritus Reader
Sobell Department of Motor Neuroscience & Movement Disorders
Institute of Neurology
University College London
Title: Following Sherrington: Integration in Intercostal Motoneurons

Abstract
Since Sherrington, the spinal motoneuron is well known as the integrator of many different inputs. However, assessing what contribution each of these sources makes to bring any motoneuron to threshold in a natural movement is mostly unknown. Respiration, as a motor act that proceeds relatively normally under experimental conditions, is very valuable in this regard and among various muscles whose motoneurons receive a respiratory signal, particularly useful data may be obtained from the intercostals.

Friday, June 15, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Ryan Reyes
Advisor: Prof. Ron Triolo
Title: Development and Metabolic Testing of a Hybrid Neuroprosthesis for Walking After Paraplegia

Abstract
Traditional commercial exoskeletons enable persons paralyzed by spinal cord injury (SCI) to regain ambulatory function. We are developing a "Muscle First" Motor-Assisted Hybrid Neuroprosthesis (MAHNP), which uses implanted neural stimulation to activate the leg muscles in order to generate the majority of the forces required for walking. Conventional commercially available exoskeletons are unable to be driven by the muscles due to having non-backdrivable transmissions at the joint, and depend on external motors at the joints for all motive power. However, the MAHNP features motorized backdrivable joints with low passive resistance which allow the user's muscles to produce the majority of forces required for ambulation. It is possible to reduce the passive resistance to near zero with active motor compensation. To inform future decisions in our exoskeleton design, we tested the effect of motorized friction compensation on the metabolic cost of using the MAHNP with able-bodied subjects. We found that the decrease of passive friction from 6 Nm of torque to 0 Nm of torque was not statistically significant. The implications of these results will be discussed, as well as our current and future development goals.

Friday, June 8, 2018
NP Seminar

8:30 am, Linsalata Alumni Center, Foster Castele Great Hall
Case Western Reserve University

Speaker: Tim Denison, PhD
Vice President of Research and Core Technology, Medtronic
Title: Designing for Value: One Positive and One Disastrous Case Study

For more information, please contact Cheryl Dudek
(216) 231-3257 cdudek@FEScenter.org

Live stream video link for each lecture at www.FEScenter.org/Seminar

Friday, June 1, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Kelsey Bower
Advisor: Prof. McIntyre
Title: Modeling deep brain stimulation of afferent axon terminals: the role of axon morphology and head model complexity

Abstract
Numerous cell types exist in the region of the subthalamic nucleus (STN), including fibers of passage, local STN cells, and terminating STN afferents. Histological studies in the rat have identified "hyperdirect" axons which originate in motor cortex and project terminating collaterals to the STN. Recent optogenetic studies, capable of dissecting the neural circuitry and selectively stimulating these distinct neural elements, suggest that cortico-STN afferents may play an important role in the therapeutic effects of DBS. The goal of this study is to identify the behavior of terminating afferents in response to DBS using a computational modeling approach.

A computational model of a branched axon terminal was generated, with a structure that mimicked hyperdirect axons. Two models of the human head were also generated, representing a simple and a realistic head model. The axon models were placed within the internal capsule of the head model in order to best represent the location of the hyperdirect pathway. Activation thresholds of terminating fibers were compared to that of diameter-matched fibers of passage to identify the effects of termination. Small diameter terminating fibers exhibited lower thresholds than diameter-matched fibers of passage, however this trend was reversed in some large diameter fibers. Results suggest that numerous parameters affect the relative excitability of terminating axons, including morphology and electrical properties of the terminal nodes.

Friday, May 25, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Joseph Marmerstein, Ph.D. Candidate, Biomedical Engineering
Advisor: Prof. Durand
Title: Chronic Recording of Rat Vagal Tone with Carbon Nanotube Yarn Electrodes

Abstract
The study of small peripheral nerves such as those in the autonomic nervous system holds great promise for the detection and treatment of a variety of pathologies. In particular, the vagus nerve, which is a highway of autonomic activity, has been receiving increased attention due to it's interaction with nearly every internal organ in the body. Additionally, vagal tone is a clinical measure that is generally correlated with patient outcomes in many diseases, leading to interest in the vagus nerve as a therapeutic target for everything from epilepsy to autoimmune disorders. However, vagal tone has never been directly measured and is only correlated to clinical factors such as heart rate variability. Dr. Durand's group has developed a novel way for interfacing with the vagus, via carbon nanotube (CNT) yarn microelectrodes. A new technique for CNT yarn implantation may increase yield and allow this technology to be more easily used by other researchers. These CNT yarn electrodes have been implanted chronically in the vagus nerve of rats, and may allow for a true measurement of vagal tone for the first time.

Note: There will not be an NEC Seminar on Friday May 11.

Friday, May 4, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Brian Sanner, Ph.D Candidate
Advisor: Prof. Tyler
Title: Verification Testing of an Inline High Density Connector for Implanted Functional Electrical Stimulation

Abstract
An inline high density connector (I-HDC) with 34 independent channels was developed to minimize volume displacement of tissue while creating a robust, chronic, system for modularizing and managing the wire leads of implanted functional electrical systems (FES). The HDC was fabricated in two configurations, a loopback (LB-HDC), which is implanted subcutaneously and has groups of channels shorted together to test connectivity and crosstalk over chronic periods, and the inline configuration, which connects the percutaneous leads to the proximal side of the HDC and the distal side to a 16-channel c-FINE. These were implanted in the feline model (n=3 and n=2, respectively) for the first round of testing to verify functional requirements, with current findings in the ongoing study to be presented here.

Friday, April 27, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Prof. Mortimer
Topic: Authorship

Prof. Mortimer has provided the following two documents for reading prior to the meeting:
Authorship (doc)
Examples (doc)

Friday, April 13, 2018
APTC Distinguished Lecture Series

11am-12pm, Cleveland Clinic Lerner Research Institute, Room NE1-205

Speaker: Shelley Fried, PhD
Title: Restoring function with neural prostheses: work towards the development of more effective stimulation strategies

Dr. Shelley Fried is a Health Scientist at the Boston VA Medical Center and an Associate Professor in the Department of Neurosurgery at Harvard Medical School, both in Boston, MA. Dr. Fried has a PhD in Vision Science from UC Berkeley where he studied the mechanisms by which the normal retina transforms light into neural signals. He did postdoctoral training at both UC Berkeley and at the Massachusetts General Hospital in Boston studying electric stimulation of the retina. His research explores how and why neurons respond to artificial stimulation with the goal of developing improved methods and strategies. Active areas of research include electric stimulation of the retina, magnetic stimulation of primary visual cortex and the function of the early visual pathways. Prior to obtaining his PhD, Dr. Fried worked for 12 years in the medical device industry developing a wide range of anesthesia and respiratory therapy products.

For more information, please go to https://friedlab.mgh.harvard.edu/

 

Friday, April 13, 2018
NP Seminar

8:30am, BRB 105

Speaker: Sliman Bensmaia, PhD
Title: Biological and Bionic Hands: Natural Neural Coding and Artificial Perception

Abstract
Our ability to manipulate objects dexterously relies fundamentally on sensory signals originating from the hand. To restore motor function with upper-limb neuroprostheses requires that somatosensory feedback be provided to the tetraplegic patient or amputee. Given the complexity of state-of-the-art prosthetic limbs, and thus the huge state-space they can traverse, it is desirable to minimize the need of the patient to learn associations between events impinging upon the limb and arbitrary sensations. With this in mind, we seek to develop approaches to intuitively convey sensory information that is critical for object manipulation - information about contact location, pressure, and timing - through intracortical microstimulation (ICMS) of primary somatosensory cortex (S1). To this end, we test in psychophysical experiments with monkeys, the sensations evoked by ICMS of S1. Based on these results, we show how to build a biomimetic encoding algorithm for conveying tactile feedback through a cortical interface and show that artificial touch improves the dexterity of brain-controlled bionic hands.

Friday, April 6, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Grant McCallum, PhD
PI: Prof. Durand
Title: "Neural activity within solid breast tumors and the implications on metastasis"

Abstract
Breast cancer is a global problem. Worldwide, breast cancer accounts for nearly a quarter of all cancers in women and it is estimated that 1.7 million women are diagnosed with the disease annually. In the United States, in 2016, 249,260 women and 2,600 men were diagnosed with invasive breast cancer, and another 61,000 women were diagnosed with in situ breast cancer. The chance of a woman being diagnosed with breast cancer during her lifetime has increased from about 1-in-11 in 1975 to 1-in-8 today. An estimated 90% of deaths due to breast cancer are a consequence of metastatic disease, whether the cancer was metastatic at diagnosis or a metastatic recurrence that developed later.

An increasing amount of evidence supports the autonomic nervous system's role in the etiology and evolution of solid tumors, including prostate, pancreas and breast. Solid tumors were once believed to lack innervation. However, recent scientific articles indicate that nerve fibers infiltrate primary tumors through neurogenesis. Increasing nerve densities are associated with more aggressive tumor grades and poor patient survival. Signaling molecules (neurotrophins, neuropeptides, axon guidance molecules and neurotransmitters) traditionally associated with nervous system function have also been implicated in cancer and may play an important role in promoting cancer by mediating the reciprocal cross-talk between nerves and cancer cells, particularly in the context of the tumor microenvironment.

Numerous animal model studies have provided a starting point to understand the autonomic nervous system's influence on breast cancer progression. However, not one of these studies has reported direct recordings and/or quantified the neural activity within the solid breast tumor to ascertain whether these neural fibers are active and if so, what neural signaling patterns are occurring within the solid tumor during its development through metastasis.

Collaborating with Prof. Karathanasis' lab and using their 4T1 (triple-negative) breast cancer mouse model, we have implanted our microwire electrodes into the solid tumor and performed chronic recordings and bioluminescence imaging (BLI) to track the neural activity and tumor growth through metastasis. Preliminary recording, imaging and histology data will be presented along with the ultra, low-noise chronic recording system setup used. We hypothesize that recorded neural activity can be used to predict the occurrence of metastasis in this animal model. Furthermore, encouraging evidence has emerged that it may be possible to differentiate pre-metastatic vs. metastatic conditions based on overall signaling patterns and a subset of the active neural population.

 

Friday, March 29, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Ivana Cuberovic
Advisor: Prof. Dustin Tyler
Title: Cognitive Factors Driving Perception of Sensory Location

Abstract
There are approximately 2 million amputees in the United States. When a person suffers an amputation, they lose both the motor capabilities of the limb and all somatosensory feedback from it. Electrical stimulation is a means of restoring sensation to such persons. Previous work in our lab has demonstrated the ability to evoke focal, intensity-graded sensations of pressure across the surface of the phantom hand.

One of the fundamental dimensions of sensation we aim to accurately reproduce with sensory stimulation is the location of evoked percepts. Tactile stimuli have been shown to improve task performance in both tactile-only and in multi-modal sensory feedback conditions when the feedback is spatially congruent to the task. We hypothesize that the anatomic relationship between peripheral nerve somatotopy and the sensory homunculus in the sensory cortex defines the possible locations of evoked sensation, but that it does not account for changes in tactile location perception under various cognitive conditions, such as those found in haptic illusions.

Here we sought to probe cognitive influences on the perception of electrically-evoked sensory locations within anatomic bounds. First, we quantified the effects of changing limb posture on perceived location. We then investigated the influence of task-performance on perceived location. Finally, we show preliminary data investigating the relative contribution of visual capture to changes in perceived location during task performance. We hypothesize that perceptual processes such as visual capture and expectation influence the precise location of perceived sensation within broad anatomic bounds.

Friday, March 23, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Platon Lukyanenko
Advisor: Prof. Dustin Tyler
Title: A muscle synergy basis for a continuous, proportional, simultaneous prosthetic hand controller allows reduced training time without performance degradation.

Abstract
Of the nearly 100k upper limb amputees in the united states, 20-40%, varying by survey, abandon their prosthetic devices. Recent pushes by groups such as DARPA and the VA have allowed the creation of advanced prosthetic limbs including the Deka and Modular Prosthetic Limb, but not yet the means for their control. Modern experimental prosthetic hand controllers generally interpret user generated EMG to determine a user's intent and then drive a prosthetic hand's motors. Rarely do these controllers allow 'simultaneous' movement of multiple degrees of freedom, variable movement speed of these degrees in a manner 'proportional' to user intent, 'continuous' combinations of movements evoked, and low training times on the user's part. We develop a synergy-based prosthetic controller which provides continuous, proportional, simultaneous hand control using implanted EMG, with the potential for very short training times, and evaluate it using a VR based posture matching task and a novel 'simultaneity' metric. Successful use of the synergy approach serves to enhance its validity as a framework for interpreting neural drives.

Friday, March 16, 2018
NP Seminar

8:30 AM, Wolstein Research Building Room 1413

Title: Interfacing with Autonomic Nerves

Speaker: Dominique Durand, PhD
Elmer Lincoln Lindseth Professor in Biomedical Engineering
Director, Neural Engineering Center
Case Western Reserve University

For more information, contact Cheryl Dudek (216) 231-3257, cdudek@FEScenter.org

Friday, March 9, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Natalie Cole
Title: "Reducing the dimensionality of time-varying hand function with muscle synergies"
Advisor: Prof. Bolu Ajiboye

Abstract
Muscle synergies have been shown to reduce the muscle activation patterns of complicated, multi-dimensional sets of movements and postures to simplified, coordinated muscle recruitment. Regarding hand function specifically, it has been shown that the complexity of hand function is physiologically simplified at the kinematic and muscle activation level as evidenced by correlated and co-varying degrees of freedom. Additionally, muscle synergies extracted from a limited set of hand postures have been successfully used to reconstruct the muscle activation patterns required to reproduce a wide range of new hand postures However, it is unclear whether static synergy modules can be used to reproduce the time-varying muscle activation patterns observed during actual hand movement (i.e. during grasp formation and functional use). This work first examines whether a low-dimensional set of static synergies can be extracted from and recreate muscle activation patterns observed during time-varying (non-isometric) hand function as well as or better than static synergies derived from (isometric) hand postures. The results show that static muscle synergies can be extracted from functional task EMG and the performance for reconstructing muscle activations during functional tasks is comparable whether using static synergies derived from postural tasks or functional tasks.

Friday, March 2, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Breanne Christie
Title: "Evaluating the functional performance and cognitive burden of lower limb sensory neuroprostheses"
Advisors: Drs. Ronald Triolo and Dustin Tyler

Abstract
Somatosensory feedback from the sole of the foot and ankle joint plays an important role in maintaining balance and postural stability. In people with lower limb loss, the feedback from foot-floor contact pressure or ankle position is compromised. Compared to able-bodied individuals, they typically have lower balance confidence, higher fall risk, and asymmetrical weight distribution. In a preliminary study, we successfully restored natural sensation in two unilateral trans-tibial amputees using chronic neural interface technology. We implanted nerve cuff electrodes on the distal sciatic, tibial, and common peroneal nerves in the residual limb. By delivering electrical pulse trains to the nerve, we were able to elicit sensations referred to the missing limb. After finding charge thresholds and mapping percept location to electrodes, we developed an instrumented prosthesis equipped with pressure sensors embedded in shoe insoles. When pressure sensors were activated, appropriate electrical stimulation was delivered to the nerve to evoke sensation in the corresponding locations of the missing limb. We have begun to examine the effects of sensory feedback on gait, static balance, and cognitive burden. During gait experiments, participants walk on a treadmill with embedded force plates. A SMART Balance Master ® with embedded force plates is used to perform two balance tests. In a sensory organization test (SOT), a surface platform sways, visual surroundings sway, and/or subjects close their eyes. During translation tests, the surface platform is unexpectedly translated forward or backward by 6cm. Finally, to assess cognitive burden, a dual-task paradigm combines static standing with spelling 5-letter words backwards. During translation tests and conditions of the SOT missing visual input, preliminary results indicate that one participant adopts a more symmetrical weight distribution when sensory feedback is incorporated. He also has decreased anterior-posterior sway (p<0.05) when visual input is blocked while the platform rotates about the ankle joint. Overall, our findings suggest that restoring sensory feedback to individuals with lower limb loss could potentially minimize overuse of their intact limb and improve postural stability in response to perturbations.

 

Friday, February 23, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Nicholas Couturier
Advisor: Prof. Durand
Title: Low-frequency fiber tract stimulation for seizure suppression in cortical epilepsies

Abstract:
Frontal Lobe Epilepsy (FLE) is the second most common form of focal epileptic disorders. FLE is characterized by highly diverse seizure symptoms often delaying accurate diagnosis. Unlike the more common temporal lobe epilepsy, FLE tends to be more refractory to anti-epileptic drug treatment accounting for up to half of all intractable epilepsies. Furthermore, the success rate of surgical resections for neocortical seizures is only 50-60% compared to 75% for temporal lobectomy. A novel treatment for refractory epilepsy of neocortical origin is investigated based on the success of previous studies in deep brain stimulation for mesial temporal lobe epilepsy. We previously reported seizure suppression of 90% in animal models as well as in patients. Seizure suppression is achieved through direct stimulation of the fiber tracts connecting structures in both hemispheres of the brain. We stimulate at low frequencies between 1-30 Hz to elicit a long-lasting hyperpolarization in the post-synaptic neurons. For epileptic foci in the frontal cortex, we stimulate the corpus callosum acutely for 1 hour to suppress seizures both during stimulation as well as after stimulation. Initial experiments demonstrate significant seizure suppression in an acute cortical model of epilepsy. Additional acute experiments, as well as chronic experiments, are being planned to validate the effectiveness of fiber tract stimulation for seizure suppression.

 

Friday, February 16, 2018
NP Seminar

8:30 AM, Wolstein Research Building Room 1413

Speaker: Julius DeWald, PhD
Chair and Professor
Department of Physical Therapy and Human Movement Sciences
McCormick School of Engineering and Physical Medicine & Rehabilitation
Northwestern University

download flyer

Friday, February 2, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Cale Crowder
Advisor: Robert Kirsch, PhD

Title: Applications of deep learning in brain-computer interfaces

Abstract:
Cervical-level spinal cord injuries can result in paralysis from the neck down -- a condition know as tetraplegia. In order to return motor function to study participants with spinal cord injuries, our research group has created an intramuscular functional electrical stimulation (FES) system controlled by an intracortical brain-computer interface (BCI). The FES-BCI system relies on many components including: a module to denoise the BCI signals, a module to extract features from the denoised signals, a decoder to translate extracted features into kinematic commands, and a controller to map kinematic commands to FES patterns. In this presentation, we will propose deep learning as a method to optimize the components of our FES-BCI system. Furthermore, we will suggest that deep learning can be used to elucidate the structure and function of the human motor cortical system.

Friday, January 26, 2018
NEC Seminar

9:00 AM, Nord 400

Speaker: Rajat Shivacharan
Advisor: Prof. Durand

Title: Spontaneous neural activity can propagate non-synaptically

Abstract:
It is well documented that synapses play a significant role in the transmission of information between neurons. However, in the absence of synaptic transmission, neural activity has been observed to continue to propagate. This raises the question as to what is mediating this propagation. Experiments conducted in our lab have shown that propagation of epileptiform behavior in rodent hippocampi propagates at a speed of ~0.1 m/s. This observed propagation can take place in the absence of synaptic transmission and gap junctions and is outside the range of ionic diffusion and axonal conduction. Recent studies suggest ephaptic coupling, or endogenous electric fields, can activate neighboring neurons, thereby generating a self-propagating wave. However, there is no experimental data suggesting ephaptic coupling is sufficient for spontaneous, self-regenerating propagation of neural activity. Recent in vitro and in vivo data from the rodent hippocampus will be presented that shows neural activity can propagate through a physical cut in the tissue, thereby completely eliminating synaptic transmission and other close cell-to-cell communication mechanisms, and showing electric fields alone are sufficient to mediate non-synaptic propagation.

Friday, January 19, 2018
NP Seminar

8:30 AM, Wolstein Research Building Room 1413

Speaker: Aaron Batista, PhD
Associate Professor, Bioengineering
Principal Investigator, Sensory Motor Integration Laboratory and Engineering
University of Pittsburgh

Title: How does the brain change when we learn?

Abstract:
How does the brain change when we learn? Those changes must lead to the emergence of new patterns of activity in the population of neurons that control the newly-learned behavior. By using a Brain-Computer Interface (BCI) paradigm, we can observe changes in neural population activity that lead directly to new behavioral capacities. We find that a simple network principle governs whether novel BCI mappings will be learned quickly or more slowly. We can then examine the neural activity patterns that are expressed following learning. We find that different principles of nework reorganization underlie fast and slow BCI learning.