Separable actions of acetylcholine and noradrenaline on neuronal ensemble formation in hippocampal CA3 circuits.

ABSTRACT: In the hippocampus, episodic memories are thought to be encoded by the formation of ensembles of synaptically coupled CA3 pyramidal cells driven by sparse but powerful mossy fiber inputs from dentate gyrus granule cells. The neuromodulators acetylcholine and noradrenaline are separately proposed as saliency signals that dictate memory encoding but it is not known if they represent distinct signals with separate mechanisms. Here, we show experimentally that acetylcholine, and to a lesser extent noradrenaline, suppress feed-forward inhibition and enhance Excitatory-Inhibitory ratio in the mossy fiber pathway but CA3 recurrent network properties are only altered by acetylcholine. We explore the implications of these findings on CA3 ensemble formation using a hierarchy of models. In reconstruc

SUBMITTER: Prince LY 

PROVIDER: S-EPMC8513881 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature