In this Thesis, I synthesize 10 years of work on the role of the motor system
in sensorimotor decision-making. First, a large part of the work we initially
performed questioned the functional role of the motor system in the integration
of so-called decision variables such as the reward associated with different
actions, the sensory evidence in favor of each action or the level of urgency
in a given context. To this end, although the exact methodology may have
varied, the approach exploited has been to study either the impact of a
perturbation of the primary motor cortex (M1) on the integration of such
decision variables in decision behavior, or the influence of these variables on
changes in M1 activity during the decision. More recently (2020 - present), we
have been investigating the neural origin of some of the changes in M1 activity
observed during decision-making. To answer this question, a
"perturbation-and-measurement" approach is exploited: the activity of a
structure at a distance from M1 is perturbed, and the impact on the changes in
M1 activity during decision-making is measured. The thesis ends up with a
personal reflection on this paradigmatic evolution and discusses some key
questions to be addressed in our field of research.Comment: This is an Habilitation Thesis, written in Frenc