Current events

Date: Jan 20th

Time: 09:30 am

Place : 2nd Floor Conference Room, Gonda building.

Title : "A disinhibitory microcircuit for associative fear learning in the auditory cortex"

Speaker: Walter Babiec, Ph.D.

Summary:

Learning causes a change in how information is processed by neuronal circuits. Whereas synaptic plasticity, an important cellular mechanism, has been studied in great detail, we know much less about how learning is implemented at the level of neuronal circuits and, in particular, how interactions between distinct types of neurons within local networks contribute to the process of learning. Here we show that acquisition of associative fear memories depends on the recruitment of a disinhibitory microcircuit in the mouse auditory cortex. Fear-conditioning-associated disinhibition in auditory cortex is driven by foot-shock-mediated cholinergic activation of layer 1 interneurons, in turn generating inhibition of layer 2/3 parvalbumin-positive interneurons. Importantly, pharmacological or optogenetic block of pyramidal neuron disinhibition abolishes fear learning. Together, these data demonstrate that stimulus convergence in the auditory cortex is necessary for associative fear learning to complex tones, define the circuit elements mediating this convergence and suggest that layer-1-mediated disinhibition is an important mechanism underlying learning and information processing in neocortical circuits.

Releavant Reading Material:

Johannes J. Letzkus1*, Steffen B. E. Wolff1,2*, Elisabeth M. M. Meyer1,2, Philip Tovote1, Julien Courtin3, Cyril Herry3 & Andreas Lu ̈thi1 (2011) Nature 480:331-335. A disinhibitory microcircuit for associative fear learning in the auditory cortex http://www.nature.com/nature/journal/v480/n7377/full/nature10674.html