Eyal Seidemann, Ph.D.

• Professor
• Department of Neuroscience
• The University of Texas at Austin

Toward “reading” and “writing” neural population codes in the primate cortex

A central goal of sensory neuroscience is to understand the nature of the neural code in a given sensory cortical area to the point where we could “read” it – i.e., account for a subject’s perceptual capabilities using only the relevant cortical signals, and “write” it – i.e., substitute sensory stimuli with direct cortical stimulation that is perceptually equivalent. Two key properties of primate sensory cortex are distributed representations and topography. In primary visual cortex (V1), for example, a localized stimulus activates millions of V1 neurons spanning multiple square mm, and neurons that are similarly tuned are clustered into sub-mm diameter columns that form overlapping, semi-periodic topographic maps. This organization raises the possibility that in some visual tasks, the neural code in V1 operates at the topographic scale rather than at the scale of single neurons. If this were the case, then the fundamental unit of information would be clusters of similarly tuned neurons (e.g., orientation Two key properties of primate sensory cortex are distributed representations and topography. In primary visual cortex (V1), for example, a localized stimulus activates millions of V1 neurons spanning multiple square mm, and neurons that are similarly tuned are clustered into sub-mm diameter columns that form overlapping, semi-periodic topographic maps. This organization raises the possibility that in some visual tasks, the neural code in V1 operates at the topographic scale rather than at the scale of single neurons. If this were the case, then the fundamental unit of information would be clusters of similarly tuned neurons (e.g., orientation columns), and to account for perceptual performance, it would be necessary and sufficient to consider the summed activity of the thousands of neurons within each column. A long-term goal of my lab is to test the topographic population code hypothesis. In this presentation, I will describe our progress toward developing bi-directional, read-write, optical-genetic tools for directly probing the nature of the neural code in behaving macaques.

Faculty Host: Dr. Xiaoqin Wang