Date and Time : Nov 7 (Thu) 3.30-5.00 pm
Venue : MMCR, EE.
Speakers : Prof. Shihab Shamma (Univ. of Maryland) and Prof. John Jeka (Univ of Delaware).
I. Neuroplasticity and the Musical Experience
Why are humans so enamored by musical sounds in all their forms? What makes music special in the human experience in ways that are absent in all other animals? In this talk I will address the experimental and computational algorithms we developed or used to study the encoding of music in the brain. I will also explain how with these algorithms we can tap into the emotional engagement with music and reveal our dynamic interactions with music on a moment by moment basis. All these studies shed new light on the emotive bases of music and the ways in which it can be enhanced and harnessed for enjoyment and health.
II. Human Bipedal Locomotion:Temporally Coordinated Mechanisms of Balance Control
Human locomotion is a complex motor behavior in which multiple constraints are satisfied that include moving the body through space, balancing to remain upright, moving a foot through space to a stepping location, avoiding obstacles in the foot’s path, and modulating the movement pattern to achieve desired movement direction and speed of the body with a desired leg cadence and step length. Current theoretical modeling suggests how the biomechanics of the body, muscle physiology, and spinal reflex loops may generate stable walking patterns but does not yet address important features of human locomotion. One of these features is the neural control of balance, which has been studied extensively in standing, using a variety of techniques with quiet unperturbed stance as well as sensory and mechanical perturbations. Despite the vast knowledge gained regarding balance control during standing, such findings do not necessarily translate to balance control during walking. The main reason is the gait cycle. While responses to disturbances during standing follow a short-medium-long latency response pattern over 50-200 ms involving a proximal-to-distal pattern (or vice versa) of muscular activation, responses to disturbances during walking can occur anytime over the much longer (600 ms) gait cycle of steady state walking. Critically, body configuration changes dramatically over the gait cycle (e.g., double vs. single stance), necessitating different mechanisms to maintain upright balance at different points of the cycle. One common principle to maintain upright balance during standing and walking is that the base of support must (on average) be kept under the body’s center of mass (CoM). The locomotion literature has focused extensively on one particular mechanism to achieve this: foot placement control. When the central nervous system (CNS) senses a movement of the CoM to the right, e.g., it changes the foot placement of the next step to the right. However, recent studies have suggested that to achieve flexible control of upright stance during walking, foot placement control is only one in a series of several temporally coordinated control actions. Consider the demands on upright stability while crossing a busy intersection with many other pedestrians. Continuous small changes in direction are required to avoid pedestrians walking towards you while progressing under the time constraints of the crosswalk signal. These small changes, essentially responses to disturbances during steady-state walking, can occur at any time during the gait cycle. To adapt flexibly, using only one balance mechanism (i.e., foot placement change) available only during a short time window of the gait cycle, is not sufficient. Instead, multiple balance mechanisms which are temporally coordinated lead to the most flexible response to disturbances while walking. I will discuss how task, environmental constraints and neurological deficits may change the availability of these mechanisms and how loss of any one of these mechanisms requires compensation from a remaining mechanism that is not optimal for flexible, stable locomotion.
Speaker Bio :
Prof. Shihab Shamma received his B.S. degree in 1976 from Imperial College, in London, U.K. He received his M.S. and Ph.D. degrees in Electrical Engineering from Stanford University in 1977 and 1980, respectively. Dr. Shamma received his M.A. in Slavic Languages and Literature in 1980 from the same institution. Dr Shamma has been a member of the University of Maryland faculty since 1984, when he started as an Assistant Professor in the Electrical Engineering Department. He has been associated with the Institute for Systems Research since its inception in 1985, and received a joint appointment in 1990. He is a fellow of the Acoustical Society of America and the Institute of Electrical and Electronics Engineers. Dr. Shamma’s research deals with issues in computational neuroscience, euromorphic engineering, and the development of microsensor systems for experimental research and neural prostheses. Primary focus has been on studying the computational principles underlying the processing and recognition of complex sounds (speech and music) in the auditory system, and the relationship between auditory and visual processing. Prof. Shamma also holds the Pratiksha Trust Distinguished Chair position at IISc.
Prof. Jeka was an NIMH predoctoral fellow and received his PhD in Neuroscience from Florida Atlantic University. He then received an NIH NRSA postdoctoral fellowship with the Ashton Graybiel Spatial Orientation laboratory at Brandeis University. After 18 years at the University of Maryland – College Park, he moved to Temple University as Professor and Chair of the Department of Kinesiology from 2013-2017 and is currently Chair of Kinesiology & Applied Physiology at the University of Delaware. His research interests include multisensory fusion for the control of human postural/locomotion and its application to the rehabilitation of individuals with balance disorders including cerebral palsy, vestibular loss and traumatic brain injury. He has received over $10 million in funding from the NIH, NSF, NASA and private sources such as the Erickson Foundation and the Shriners Foundation. He currently has two patents pending and is the Chief Scientific Officer of Treadsense, Inc., which develops technology for enhanced mobility.