Dr. Eyal Seidemann
Office: Seay 4.204
phone: (512) 232-6052
Eyal Seidemann received his undergraduate and Masters degrees from Tel Aviv University in Israel. Dr. Seidemann conducted his graduate studies at Stanford University and obtained his Ph.D in Neuroscience in 1998. He then pursued his postdoctoral work with Amiram Grinvald at the Weizmann Institute of Science in Israel, where he was the first recipient of the Koshland Scholarship. Dr. Seidemann joined the faculty at the University of Texas at Austin in the Fall of 2002. He is currently Assistant Professor of Psychology and Neurobiology and a member of the Center for Perceptual Systems. Dr. Seidemann was recently selected as a Sloan Research Fellow by the Alfred P. Sloan Foundation.
How are sensory information and motor commands represented and processed in the brain? A fundamental feature of many sensory and motor areas is the use of orderly maps for the representation of sensory and motor signals. In these maps, the value of the parameter computed by individual neurons (e.g., the orientation of a line segment; the direction and amplitude of a planned eye movement) changes systematically across one or two dimensions of a neural structure. These maps serve as powerful computational machines, allowing highly efficient parallel processing of sensory or motor information. Incoming neural signals, therefore, are rapidly transformed into a ‘place code’ – where the spatial pattern of activity within the map conveys information about a sensory stimulus or a planned movement. Because sensory and motor neurons are typically coarsely tuned, that is, each neuron responds to a broad range of stimulus or movement parameters, any stimulus or motor response elicits neural activity that is distributed over a large population of neurons within the neural map.
A central goal of my research is to understand how spatiotemporal patterns of activity in large populations of coarsely tuned neurons lead to highly specific visual percepts and precise motor responses. To address this question, we employ a novel combination of optical imaging and electrophysiological techniques in awake, behaving primates. These methods allow us to: 1) determine the functional organization (the layout of neural map/s) of a given cortical area quickly and efficiently, and 2) monitor the activity of large populations of neurons at high spatial and temporal resolutions, in a behaving animal. We repeatedly measure reliable optical signals (voltage sensitive dye and/or intrinsic) from the cortex of alert behaving primates for periods of several months. Furthermore, we combine optical imaging with simultaneous single unit recording, microstimulation or microinjections of pharmacological agents.
These techniques put us in a unique position – they allow us to directly visualize the functional organization and the spatial pattern of population activity in cortical maps in real-time, while subjects perform demanding, well controlled, perceptual, cognitive, or motor tasks. We then build computational models that attempt to explain how the measured neural activity could lead to the observed behavior. Finally, we test the predictions of these quantitative models by measuring how perceptual judgments or motor plans change following selective manipulations of the neural response by microstimulation or pharmacological microinjections. Taken together, we believe that this line of research can lead us to a better understanding of the neural basis of perception and action. We hope that this understanding will prove to be valuable in the development of better diagnosis and treatment of the many diseases that devastate the lives of individuals who suffer from cortical function disorders.
Chen, Y., Geisler, W.S. & Seidemann, E. (2008) Optimal temporal decoding of V1 population responses reaction-time detection task. Journal of Neurophysiology (in press). [PDF]
Palmer, C.R., Cheng, S.Y., & Seidemann, E. (2007). Linking Neuronal and Behavioral Performance in a Reaction-Time Visual Detection Task. The Journal of Neuroscience, 27(30):8122-8137 [PDF]
Yang, Z., Heeger, D., & Seidemann, E. (2007). Rapid and precise retinotopic mapping of the visual cortex obtained by voltage sensitive dye imaging in the behaving monkey. Journal of Neurophysiology, 98(2): 1002-1014 [PDF]
Dynamics of depolarization and hyperpolarization in the frontal cortex and saccade goal. E. Seidemann, A. Arieli, A. Grinvald, H. Slovin. Science 2002 Feb 1;295(5556):862-5. [PDF]
Color signals in area MT of the macaque monkey. E. Seidemann, A. B.
Motion opponency in visual cortex. D.J. Heeger, G.M. Boynton, J.B. Demb, E.
Effect of spatial attention on the responses of area MT neurons. E. Seidemann, W.T. Newsome. J Neurophysiol. 1999 Apr;81(4):1783-94. [PDF]
Temporal gating of neural signals during performance of a visual
Simultaneously recorded single units in the frontal cortex go through sequences of Discrete and stable states in monkeys performing a delayed localization task. E. Seidemann, H. Bergman, E. Vaadia M. Abeles. J Neurosci. 1996 Jan 15;16(2):752-68. [PDF]