Meeting Abstract
Rats are expert at navigating the world in the dark using their sense of touch. They rhythmically brush and tap about 60 large vibrissae (whiskers) against objects to determine size, shape, orientation, and texture. At the same time, rats also use their whiskers to help sense the direction of airflow, likely aiding in the localization of odor sources. In this talk I will describe the results of three recent studies that investigate how rats use whisker-based touch and airflow information to guide their exploratory behavior. The first experiment demonstrates that in a novel, unfamiliar environment, rats prefer to explore with their heads pitched to orientations that maximize the expected value of whisker contacts with a surface at an unknown distance. In other words, rats tilt their heads in a way that will tend to maximize the number of whiskers that will come into contact with a surface, given that the surface could be at any possible distance from the rat. The second experiment demonstrates that the relationship between right-left whisker asymmetry and head motion changes as the rat gains familiarity with the environment. Finally, the third experiment demonstrates that sensory feedback from the whiskers is important for anemotaxis. Five rats trained on a five-alternative forced-choice airflow localization task exhibited significant performance decrements after vibrissal removal. In contrast, vibrissal removal did not disrupt the performance of control animals trained to localize a light source. Simulation results suggest that changes in head pitch could aid in this airflow localization behavior. Together, these three studies lead to an understanding of rat exploratory behavior in which head pose is the primary factor that determines the overall spatial structure of input across the array, while individual whiskers drive the temporal structure that guides subsequent head movements.
