onLINe Seminar

Prof. Johannes Letzkus (University of Freiburg)

“A thalamo-cortical top-down circuit for associative memory”

16.04.2021

2 p.m.

https://ovgu.zoom.us/j/3628581343

Passcode: onLINe

Abstract:

Sensory neocortex is a critical substrate for memory. Despite its strong connection with the thalamus, the role of direct thalamo-cortical communication in memory remains elusive. We performed chronic in vivo 2-photon calcium imaging of thalamic synapses in auditory cortex layer 1, a major locus of cortical associations. Combined with optogenetics, viral tracing, whole-cell recording and computational modeling, we find that the higher-order thalamus is required for associative learning, and transmits memory-related information that closely correlates with acquired behavioral relevance. In turn, these signals are tightly and dynamically controlled by local presynaptic inhibition. Our results not only identify higher-order thalamus as a highly plastic source of cortical top-down information, but also reveal a level of computational flexibility in layer 1 that goes significantly beyond hard-wired connectivity.