Meeting Abstract

S1.7  Sunday, Jan. 4  Mechanical and Behavioral Constraints on Neural Encoding in the Rat Vibrissal/Trigeminal Pathway HARTMANN, Mitra JZ; Northwestern University m-hartmann@northwestern.edu

Rats are nocturnal, burrowing animals that use their vibrissae (whiskers) to tactually explore the environment. Using only its whiskers, a rat can determine object size, shape, orientation, and texture. This makes the rat vibrissal system an excellent model to explore the structure of movements that subserve sensing. I will describe recent experiments in our laboratory that have aimed to understand neural encoding and processing in the vibrissal system using both a "bottom-up" and a "top-down" approach. In the bottom-up approach, a basic analysis of whisker mechanics has provided insight into the physical variables (forces and moments) encoded by primary sensory neurons in the trigeminal ganglion. This analysis has suggested some mechanisms by which the animal might determine the radial distance to an object. In the top-down approach, behavioral studies have helped to constrain the types of neural processing that may enable object localization in the horizontal plane. Our laboratory now aims to merge the two approaches using a new laser-light sheet technology developed to visualize whisker-object contact patterns. I will describe some preliminary results from this system and suggest some ways that the nervous system may interpret the spatiotemporal "flow" of sensory information across the whisker array during natural exploratory behaviors.