A directed form of plasticity drives experience-dependent hippocampal representations
A crucial function of the brain is to produce useful representations of the external world. These representations are used to form a cellular memory of past experiences, which can be recruited to guide present behaviors. However, the nature of the neuronal code and the mechanisms used to create, maintain, and recall neuronal representations remain unsolved. As a result, we still know very little about how representations embedded within neuronal circuits are actually used by the brain to guide goal-directed, adaptive behaviors.
We previously demonstrated that a non-Hebbian type of synaptic plasticity, behavioral timescale synaptic plasticity (BTSP), has a fundamental role in forming experience-dependent representations in hippocampal area CA1. BTSP has several distinct characteristics, including that it is driven by dendritic plateau potentials (plateaus) instead of APs. Axons from layer 3 entorhinal cortex (EC) impinge onto the site of dendritic plateau initiation, the apical tuft of CA1 pyramidal neurons, and their activity regulates plateau probability. In this talk, I will focus on our most recent data that indicate that an incoming signal from the EC3 directs learning-related activity changes in the hippocampal CA1 network. These results identify EC3 input as a key signal that instructs CA1 neurons – by driving BTSP – in how to represent an experience.
Brandeis University, Department of Biology