Surviving in dynamic environments requires to arbitrate between the exploration of new options to gain more information or to exploit already known ones to secure a gain. The control of these voluntary actions relies on a highly distributed cortical-subcortical circuits among which secondary motor regions (M2) now emerge as critical integrative nodes. In this PhD project, we propose to examine the role of thalamocortical circuits constituted by connections between M2 and two key thalamic nuclei – the mediodorsal (MD) and the ventral anterior/ventral lateral thalamic (VAVL) nuclei – in the ability to decide between exploration or exploitation actions. We hypothesize that thalamocortical projections to M2 can differentially support exploration (MD-M2) and exploitation (VAVL-M2) actions. This project will be co-supervised by Frédéric Gambino (IINS) to (1) examine the fine architecture of the M2-MD/VAVL circuits with advanced neuroanatomy techniques and (2) test the causal role of thalamocortical projections at the behavioral level by selectively suppressing MD-M2 or VAVL-M2 projections. We may also consider examining the functional connectivity between M2 and thalamic regions through either multi-site electrophysiology (collaboration with Lisa Roux, IINS) or fiber photometry, as rats switch from exploitation to exploration in a three-armed instrumental bandit task. We hope to reveal the neural underpinnings of voluntary actions, which may highlight the functional principles at play within these neural circuits as they are affected in multiple psychiatric conditions.
An innovative behavioral paradigm to capture the exploration/exploration trade-off in rodent (a three-armed instrumental bandit task)
Targeted chemo- and/or optogenetic interventions on thalamocortical pathways
Multi-site electrophysiology or fiber photometry in behaving rats
Interest for cognition and behavioral procedures is primordial. Prior experience of neuroanatomy and rodent handling is an advantage but not mandatory. High motivation, willingness to work autonomously and to contribute to the team life is essential.