The Bernstein Center for Computational Neuroscience Freiburg

Announcement for the next
BCCN Seminar
Prof. Ehud Ahissar
Weizmann Institute of Science

Active sensation: how rats localize objects via whisking
Monday, March 27th, 2006
Lecture Hall (ground floor)
BCCN building
Hansastraße 9A
79104 Freiburg
Mammals acquire much of their sensory information by actively moving their sensory organs. Rats, in particular, scan their surrounding environment with their whiskers. This form of active sensing induces specific patterns of temporal encoding of sensory information, which are based on a conversion of space into time via sensor movement. We investigate the ways in which object location is encoded by the whiskers and decoded by the brain. Recordings were made in anesthetized rats during epochs of artificial whisking induced by electrical stimulation of the facial motor nerve. Recordings from first-order peripheral neurons located in the trigeminal ganglion revealed: 1) a 3D-to-3V encoding of object location, in which each spatial dimension is encoded by a different neuronal variable, and 2) separation between encoding of sensor movement (whisking) and touch. Recordings from the thalamus revealed separation of whisking and touch signals to separate nuclei. These findings give rise to several hypothetical schemes for central decoding of object location and for hierarchical organization of motor-sensory-motor loops.
The talk is open to the public. Guests are cordially invited!