Physiology Brownbag Seminars – Fall 2018

Physiology Brownbag Seminars – Fall 2018

Physiology “brown-bag” lunchtime seminars are held twice a month on WEDNESDAYS at noon in Applied Physiology Building, room 1253 (or as indicated). Special seminar dates/times outside of the regular schedule are indicated as such.

Contact Dr. Boris Prilutsky, boris.prilutsky@biosci.gatech.edu, to be considered as a future speaker, added to the e-mail distribution list, if you would like to meet with a speaker, or for other seminar-related inquiries.
For directions: Applied Physiology

SEMINAR: Wednesday, September 5, 2018

Thalamo-Cortical Networks Controlling Shoulder, Elbow, and Wrist during Locomotion

Irina I. Beloozerova, PhD
Department of Neurobiology
Barrow Neurological Institute

Abstract

Results of a number of studies suggest that movements of different segments of the limb are controlled differently during locomotion. Several lines of evidence suggest that distinct neuronal mechanisms underlie the difference in the control. These mechanisms, however, have been never explicitly studied until recently. In my talk, I will present our findings of differential activities of the shoulder, elbow, and wrist-related populations of neurons in the thalamo-cortical network during simple locomotion and accurate stepping on a complex terrain.

In chronically instrumented cats walking on a flat surface and along a horizontal ladder we have recorded the activity of single neurons in the primary motor and somatosensory cortices, and all neurons from motor cortex and many from somatosensory cortex were identified as pyramidal tract projecting neurons (PTNs, Stout and Beloozerova, 2012; Favorov et al., 2015). We have also recorded the activity of neurons in the motor thalamus, most of which were identified as thalamo-cortical projecting neurons (TCs) of the ventrolateral thalamus (VL, Marlinski et al., 2012a). In addition, we have recorded the activity of inhibitory interneurons of the motor compartment of the reticular nucleus of the thalamus (RE, Marlinski et al., 2012b; Marlinski and Beloozerova, 2014). We grouped the neurons according to the location of their receptive field into shoulder-, elbow, and wrist/paw-related subpopulations. We compared the step cycle-related activity of these subpopulations within each of the motor centers, as well as the activity of populations with the same receptive field from different centers. We found significant differences in both comparisons.

Our data suggest strategic differences in the thalamo-cortical controls for the shoulder, elbow, and wrist during locomotion (Beloozerova et al., 2013). The activity of the RE is at the heart of these differences. Commands controlling the shoulder only moderately activate inhibitory RE neurons, so the ascending thalamo-cortical signals related to the shoulder, which come from the cerebellum and spinal cord, can reach motor cortex at any time during the stride. In contrast, commands controlling the wrist significantly enhance the activity of inhibitory RE neurons during the swing phase. This is likely to attenuate thalamo-cortical signals during the swing phase, so that other inputs to motor cortex such as inputs along the cortico-cortical pathways may have a larger contribution to the control of the motor cortical output related to the wrist during the swing phase of the stride.

  BIO:Dr. Irina Beloozerova studies the organization and function of motor systems, particularly, neuronal mechanisms and biomechanics of locomotion and posture. Her goal is to understand how locomotion and posture are controlled by the nervous system and adapt to the environment. Irina has investigated the mechanisms of locomotion and posture in mollusks, rabbits, cats, and non-human primates. Her latest work is in chronically instrumented and freely behaving cats. In these experiments, she uses single-unit recordings, biomechanical analysis, and pharmacological and optogenetic manipulations to understand the organization of locomotion and posture.Dr. Irina Beloozerova graduated in 1981 from the Lomonosov University in Moscow, Russia, with a degree in biology. She received her early training in neuroscience as a Master’s student working in mollusks under Drs. Orlovsky and Arshavsky. Thereafter, Irina worked 12 years in the Soviet Space program studying limbsand eye-head coordination in Rhesus monkeys. During that time she also completed her PhD as a self-directed study of cortical mechanisms of visually guided locomotion in cats. Her postdoctoral training was with Dr. Armstrong at the University of Bristol, UK; Dr. Rossignol at the University of Montreal, Canada; and Dr. Swadlow at the University of Connecticut, USA. Irina has been a faculty member of the Barrow Neurological Institute in Phoenix, Arizona since 2000. She established two research programs: one in the thalamo-cortical mechanisms of visually guided locomotion and another, in the supra-spinal control of posture. Irina’s laboratory has been funded by several NIH R01 grants, two smaller NIH awards, and an NSF grant. Irina published 58 full size research papers and 10 reviews, and founded a Cat-Brain database, an open database of cat neuronal activity and body biomechanics.

Host: Boris I. Prilutsky, PhD
Time: 12:00 – 1:00 PM
Location: Applied Physiology Building, Room 1253

SEMINAR: Wednesday, September 19, 2018

The road to genetic targeting of distinct classes of sensory afferent in rodents, and an application to spinal cord injury

Andrew Spence, PhD
Department of Bioengineering
Temple University

Abstract

How do animals use information from peripheral sense organs when they move? Long, distinguished scientific lineages have given insight into this question, both at the level of how these organs function, and how their input is integrated with more central nervous structures. Despite standing on the shoulders of these giants, interesting open questions remain; what is the relative contribution of different classes of sensory afferent to specific locomotor tasks? how is sensory feedback used as a function of phase? and to what extent can modulating sensory feedback be useful in treating neuromuscular disease or injury, and understanding mechanisms of recovery from injury? This talk will present ongoing work that seeks to use genetic tools to target and manipulate the activity of specific classes of sensory afferent in intact rodents. Early work using optogenetics in mice will be presented, followed by recent work using DREADDs to excite or inhibit large diameter afferents in rats. DREADDs are drug-activated, engineering receptors that allow remote activation or inhibition of neurons. Results of pilot work applying selective afferent modulation by DREADDs to both enhancement of the recovery from spinal cord injury, and to understanding the mechanisms underlying that recovery, in rats, suggest that this approach holds promise. Current limitations of genetic approaches will be discussed, and a risky foray into what may lie ahead will be presented.

BIO: Andrew Spence is an applied physicist by training who leads a research group in animal locomotion. As a group, we are focused on how the nervous and mechanical systems work together to produce movement, taking an integrative approach that combines experimental work with mathematical modeling,  instrumentation, and some robotics. Andrew did his undergraduate work in physics at UC Berkeley, before doing a PhD in neuroscience and biomedical microdevices at Cornell University. He returned to Berkeley for a postdoc, and worked with Bob Full on the control of many-legged locomotion.

Before coming to Temple University, he was a faculty member in the Structure and Motion Laboratory at the Royal Veterinary College, London, working with Alan Wilson before becoming an independent researcher. Currently his group is focused on the role of constraints (stability, energetics) in shaping quadrupedal gait control, and in applying new neurogenetic techniques (chemogenetics in the form of DREADDs; optogenetics) to dissect the control of fast legged locomotion and to better treat spinal cord injuries.

Host: Greg Sawicki, PhD
Time: 12:00 – 1:00 PM
Location: Applied Physiology Building, Room 1253

 

SEMINAR: October 17, 2018

Prosthetic configuration affects running biomechanics and economy for athletes with transtibial amputations

Owen Beck, PhD
Departments of Mechanical Engineering and Biological Sciences
Georgia Tech

Abstract

Athletes with transtibial amputations use running-specific prostheses to run. Running-specific prostheses are passive-elastic carbon-fiber devices that attach in-series to residual limbs. These devices are available across many different models, stiffness categories, and heights. Typically, prosthetic stiffness and height are set based on the respective manufacturer’s recommendation. This talk presents evidence that current prosthetic model, stiffness, and height recommendations do not optimize running biomechanics or economy for athletes with unilateral or bilateral transtibial amputations. Therefore, the distance-running performance of athletes with transtibial amputations can be further enhanced by updating prosthetic configuration recommendations.

  BIO: Owen Beck is a postdoc in Dr. Greg Sawicki’s Physiology of Wearable Robotics Lab. He has a B.S. in Kinesiology from Humboldt State University and a Ph.D. in Integrative Physiology from the University of Colorado Boulder. For his doctorate, Owen investigated how prosthetic configuration affects distance-running and sprinting performance for athletes with unilateral and bilateral transtibial amputations. At Georgia Tech, Owen’s research focuses on tuning assistive devices to biological leg characteristics, with the goal of augmenting locomotion performance.

Host: Greg Sawicki, PhD
Time: 12:00 – 1:00 PM
Location: Applied Physiology Building, Room 1253

SEMINAR: October 19, 2018

Exploring energetics in locomotion control: From reduced gravity to running into walls

John Bertram, PhD
Professor, Cumming School of Medicine
Adjunct Professor of Veterinary Medicine
Director, Biomedical Engineering Graduate Program
University of Calgary

Abstract

Features of gait are determined at multiple levels, from the selection of the gait itself (eg. walk or run) and for the specific parameters utilized (stride length, frequency, etc.). The ultimate choices are neurally determined, but what is involved with that decision process? Human locomotion appears stereotyped, but evidence is accumulating that normal walking and running are solutions relevant only to normal circumstances. Under different circumstances the appropriate solution may differ broadly (different gait) or subtly (different parameters). Interpretation of the neural decision making process would benefit from understanding the influences at work. In this presentation the hypothesis that energetic cost plays a key part in motor strategy determination is evaluated through the analysis of strikingly non-normal locomotion conditions: simulated reduced gravity and the horizontal to vertical transition used to scale walls in the sport of parkour.

  BIO: John EA Bertram received his BSc (zoology) and MSc (zoology/ comparative biomechanics) degrees from the University of British Columbia. He received his PhD from the University of Chicago (anatomy/biomechanics) and did post-doctoral training at Dalhousie (Biology) and Harvard (Concord Field Station – animal locomotion – and Harvard Forest – tree stability). He held faculty positions at Ithaca College, Cornell University and Florida State University before joining the McCaig Institute in 2004. He is currently Professor in the Cumming School of Medicine and Adjunct Professor of Veterinary Medicine at the University of Calgary, Adjunct Professor at Edith Cowan University, Perth, Australia and serves as the Director of the Biomedical Engineering Graduate Program.

Host: Young-Hui Chang, PhD
Time: 3:30 – 4:30 PM
Location: Applied Physiology Building (555 14th Street NW), Room 1253

SEMINAR: October 24, 2018

Title: Coping with pathological and physiological instability of gait: spatiotemporal organization of multi-muscle activity

Giovanni Martino, PhD
Emory University School of Medicine

Abstract

Although the control of locomotion seems to be an easy and automatic process, behind this apparent simplicity there is a remarkable combination of mechanical principles, neural control, and sensory input leading to efficient muscular movements of limbs. Understanding motor control and learning even for a simple movement is a big endeavor due to the many variables that come into play. How does the nervous system harness the redundancy and the large number of degrees of freedom of the musculo-skeletal system? What is the specific role of spinal, supraspinal and proprioception systems in generating rhythmic locomotor behavior? These and other similar fundamental questions concerning the motor control mechanisms are still an open issue in neuroscience. Addressing these challenges may also have important implications in the clinical scenario. Indeed, even in the presence of small lesion of the central nervous system (CNS), patients can suffer profound locomotor impairments. Motoneurons represent the ‘final common pathway’ of the CNS and thus one may infer about what is being programmed in the CNS by evaluating the spatiotemporal motoneuron locomotor output. To get insights into the functioning of locomotor controllers, the main focus of this talk is placed on the analysis of the spatiotemporal organization of multi-muscle activity patterns in normal and pathological gait.

  BIO: Dr. Giovanni Martino’s research interests are largely directed towards understanding the neural control and the biomechanics of human movement in both normal and pathological conditions. In 2012, he obtained his Master’s Degree in Bioengineering (at Roma Tre University) with a thesis titled “Muscle synergies in patients with Parkinson’s Disease”, supervised by Prof. Silvia Conforto. After graduating, he began his work experience as Research Assistant at the Centre of Space Bio-medicine at the University of Rome “Tor Vergata” led by Prof. Lacquaniti, and in collaboration with the Laboratory of Neuromotor Physiology at IRCSS Santa Lucia Foundation under the supervision of Prof. Ivanenko and Prof. Andrea d’Avella. During this period, he conducted a series of studies about locomotor coordination in patients. In 2014, he started his Ph.D. in Neuroscience during which he was involved in several projects related to the spatiotemporal architecture of multi-muscle activity in both normal and pathological adult gait, and control of locomotion in children. In particular, the PhD project focused on the exploration of how healthy subjects and patients with neurological disorders (Parkinson’s disease, Cerebellar Ataxia, Cerebral Palsy, Hereditary Spastic Paraplegia) adapt locomotor patterns to the environment, by applying recognition algorithms to the multi-muscle activation profiles. These activities have resulted in publishing 9 articles (3 of them as the first author) in various peer-reviewed journals (Journal of Neurophysiology, Plos One, Frontiers in Physiology, Cerebellum, Clinical Biomechanics, Clinical Neurophysiology). Giovanni Martino recently graduated from the University of Rome Tor Vergata’s Neuroscience Ph.D. program. Currently, he is a postdoctoral research fellow in the lab of Dr. Lena Ting at Emory University School of Medicine.

Host: Boris I. Prilutsky, PhD
Time: 12:00 – 1:00 PM
Location: Applied Physiology Building, Room 1253

 

SEMINAR: November 14, 2018

Title: Principles and Applications of Regenerative Rehabilitation in Musculoskeletal Disease and Injury

Nick J. Willett, PhD
Department of Orthopedics
Emory University School of Medicine

Abstract

The field of tissue engineering and regenerative medicine has long integrated fundamental principles of stem cell biology, biomaterials and mechanical engineering to better design new tissues. As regenerative technologies become more prevalent in the clinic, however, it is becoming increasingly apparent that the rehabilitation regimen and management of the intervention after the delivery/implantation is just as critical to the success of the implant as the fundamental technology itself. The research of the Willett lab focuses on a systems integration approach to musculoskeletal disease and regenerative engineering by applying novel imaging and engineering techniques to clinical motivated challenges. The lab’s current work has three main thrusts: (i) cell and biologic therapies for the healing of large bone and muscle defects, (ii) multi-scale mechanical regulation of bone regeneration, and (iii) intra-articular therapeutic delivery for post-traumatic osteoarthritis. This seminar will discuss fundamental principles to Regenerative Rehabilitation and show how we utilize these rehabilitation principles to enhance the therapeutic efficacy of regenerative and tissue engineering therapies.

  BIO:  Nick Willett is an Assistant Professor in the Department of Orthopaedics at Emory University and runs a research lab with a focus on engineering strategies for musculoskeletal regeneration and rehabilitation. Nick has a secondary appointment in the joint Biomedical Engineering Department between Emory University and Georgia Institute of Technology as well as an appointment in the Research Division at the Atlanta VA Medical Center. Nick performed his postdoctoral training at the Georgia Institute of Technology working with Prof. Robert Guldberg in Mechanical Engineering. He received his Ph.D. (2010) in Biomedical Engineering from the joint program between Georgia Institute of Technology and Emory University. Prior to his graduate work he received his B.S. (2005) in Mechanical Engineering from the University of Colorado at Boulder. Nick has been an active member of TERMIS since 2011 and is a member of the TERMIS thematic group on Regenerative Rehabilitation. He is the Emory Representative for the International Consortium on Regenerative Rehabilitation and was on the scientific organizing committee for the 2016 Alliance for Regenerative Rehabilitation Research and Training, Regenerative Rehabilitation Symposium. He has received numerous awards and honors including the Gandy Diaz Teaching Fellowship from Georgia Tech, the Young Investigator Award from the American Society for Bone and Mineral Research, and the Ruth L. Kirschstein National Research Service Award Postdoctoral Fellowship from the NIH. Nick has published 24 peer reviewed manuscripts—including multiple in Tissue Engineering—and 4 book chapters. He has served as a reviewer for grant proposals for the Arthritis Foundation and applications for the Petit Scholars program at Georgia Tech. He currently reviews for numerous journals including Tissue Engineering, Biomaterials, and Acta Biomaterialia, among numerous others. The research of the Willett lab focuses on a systems integration approach to musculoskeletal disease and regenerative engineering by applying novel imaging and engineering techniques to clinical motivated challenges. The lab’s current work has three main thrusts: (i) cell and biologic therapies for the healing of large bone and muscle defects, (ii) multi-scale mechanical regulation of bone regeneration, and (iii) intra-articular therapeutic delivery for post-traumatic osteoarthritis. The Willett lab sits at the interface between the engineering and clinical disciplines and is composed of engineering students, medical students, residents, and fellows

Host: Young C. Jang, PhD
Time: 12:00 – 1:00 PM
Location: Applied Physiology Building (555 14th Street NW), Room 1253

 

SEMINAR: November 28, 2018

Neuroprostheses to promote communications between the nervous and musculoskeletal systems

Hangue Park, PhD
Department of Electrical and Computer Engineering
Texas A&M University

Abstract

Proper communications between the nervous and musculoskeletal systems is important for movement organization using feedback and feedforward control. If these communications are disrupted by peripheral nerve injury or neuropathy, spinal cord injury, etc., the patient encounters difficulties with control of movement. These difficulties potentially could be overcome with the use of prosthetic devices that provide communication channels between the nervous and musculoskeletal systems. The prosthetic devices modulate motor commands and/or sensory feedback, based on neural signal and sensor inputs. In this talk, I will discuss the development of neuroprostheses integrated with the body and their potential for enhancements of rehabilitative outcomes and augmentations of human abilities

  BIO: Hangue Park is currently an assistant professor in Electrical and Computer Engineering at Texas A&M University. He is also affiliated with the Texas A&M Institute for Neuroscience, Institute for Rehabilitation and Research (TIRR) Foundation, and Texas Brain & Spine Institute, as a research faculty. He received his Ph.D. in Electrical and Computer Engineering at Georgia Institute of Technology, in 2017. Before joining Georgia Tech, he received B.S. and M.S. in Electrical and Computer Engineering from Seoul National University, Seoul, Korea, in 2006 and 2008, respectively. He also has 5+ years of industrial experience at multiple companies including Samsung Electronics. He is a recipient of the Trainee Professional Development Award from Society for Neuroscience in 2017, the Outstanding Research Award from the Association of Korean Neuroscientists in 2016, and the Best Demonstration Award at the IEEE Biomedical Circuits and Systems Conference in 2012.

Host: Boris I. Prilutsky, PhD
Time: 12:00 – 1:00 PM
Location: Applied Physiology Building, Room 1253