Seminar – Lionel Dahan

Abstract

Long term potentiation (LTP) is one of the mechanisms underlying learning and memory. However, a hippocampus relying purely on Hebbian rules should encode every single event, which does not seems to be the case. This led theoreticians to propose a NeoHebbian framework in which the conjunction between pre- and post-synaptic activity requires a third factor – a neuromodulator playing the role of a teaching signal – in order to trigger long lasting synaptic plasticity. We used electrophysiology, optogenetics and behavior to show that VTA dopamine neurons innervating the hippocampus can operate as a teaching signal that triggers NeoHebbian LTP and promotes contextual learning.