Event:

Memories are encoded within sparsely distributed neuronal ensembles. Using Arc-dVenus immediate early gene reporter mice, we have been able to visually-identify and electrophysiologically characterize neuronal ensembles specifically recruited during fear learning. In the lateral amygdala (LA), Arc+ neurons have enhanced intrinsic excitability and are preferentially recruited into newly encoded memory traces. Furthermore, synaptic potentiation of thalamic inputs to the LA during fear conditioning are learning-specific, postsynaptically mediated and highly localized to the Arc+ neuronal ensemble. Taken together, our findings validate the immediate-early gene Arc as a molecular marker for the LA neuronal ensemble recruited during fear learning. Moreover, these results establish a model of fear memory formation in which intrinsic excitability determines neuronal selection, whereas learning-related encoding is governed by synaptic plasticity.

Afterwards lunch for Phd students.