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Behavioral/Systems/Cognitive Layer-Specific Touch-Dependent Facilitation and Depression
 

Summary: Behavioral/Systems/Cognitive
Layer-Specific Touch-Dependent Facilitation and Depression
in the Somatosensory Cortex during Active Whisking
Dori Derdikman, Chunxiu Yu, Sebastian Haidarliu, Knarik Bagdasarian, Amos Arieli, and Ehud Ahissar
Department of Neurobiology, The Weizmann Institute of Science, Rehovot 76100, Israel
Brains adapt to new situations by retuning their neurons. The most common form of neuronal adaptation, typically observed with
repetitive stimulations of passive sensory organs, is depression (responses gradually decrease until stabilized). We studied cortical
adaptation when stimuli are acquired by active movements of the sensory organ. In anesthetized rats, artificial whisking was induced at
5 Hz, and activity of individual neurons in layers 25 was recorded during whisking in air (Whisking condition) and whisking against an
object (Touch condition). Response strengths were assessed by spike counts. Input-layer responses (layers 4 and 5a) usually facilitated
during the whisking train, whereas superficial responses (layer 2/3) usually depressed. In layers 2/3 and 4, but not 5a, responses were
usually stronger during touch trials than during whisking in air. Facilitations were specific to the protraction phase; during retraction,
responses depressed in all layers and conditions. These dynamic processes were accompanied by a slow positive wave of activity pro-
gressing from superficial to deeper layers and lasting for 1 s, during the transient phase of response. Our results indicate that, in the
cortex, adaptation does not depend only on the level of activity or the frequency of its repetition but rather on the nature of the sensory
informationthatisconveyedbythatactivityandontheprocessinglayer.Theinputandlaminarspecificitiesobservedhereareconsistent
withthehypothesisthattheparalemniscallayer5aisinvolvedintheprocessingofwhiskermotion,whereasthelemniscalbarrelsinlayer
4 are involved in the processing of object identity.
Key words: active touch; adaptation; lemniscal; paralemniscal; barrels; whisker
Introduction

  

Source: Ahissar, Ehud - Department of Neurobiology, Weizmann Institute of Science

 

Collections: Biology and Medicine