The Motor System at the heart of our Decisions and Actions
Gerard Derosiere, CRCN INSERM, Centre de Recherche en Neuroscience de Lyon

The neural bases of decision-making have historically been considered through the lens of a serial perspective, which considers behavior as resulting from a serial progression of perceptual, cognitive, and motor processes. In this view, certain structures such as the orbitofrontal cortex, ventromedial prefrontal cortex, or the dorsolateral prefrontal cortex, would first implement the cognitive process – decision-making – before signaling to motor structures, such as M1, the action to be outputted. However, during the 2000s, various experimental data challenged the validity of this serial vision, particularly in the context of motor decision-making, showing that certain structures in the motor system also exhibit changes in neural activity during the decision phase, even when there is no movement to execute. These findings led to the proposition that motor structures are not solely involved in movement execution but continuously specify action possibilities offered by the environment. According to this alternative, parallel perspective, decision-making would result from neural processes occurring in parallel within sensorimotor structures and other brain regions. In this view, action possibilities would evoke increased activity within different neural populations of the motor system, and engagement in a given movement would emerge when activity reaches a triggering threshold in one of these populations. Thus, the observed activity changes within the motor system would play a decisive role in decision-making and determine whether an action is eventually chosen and executed or not. In this talk, I will present neural data acquired in humans using brain stimulation approaches and EEG showing that a multitude of cognitive variables bias motor activity during decision-making, bringing activity closer to or further from the action initiation threshold and consequently increasing or decreasing the probability of initiating certain actions. These variables include the reward associated with different actions1,2,3 , the level of sensory evidence in favor of each action4,5 and the level of urgency in
a given context6.

1. Derosiere, G., Zénon, A., Alamia, A., & Duque, J. (2017). Primary motor cortex contributes
to the implementation of implicit value-based rules during motor decisions. NeuroImage,146, 1115-1127.
2. Derosiere, G., Vassiliadis, P., Demaret, S., Zénon, A., & Duque, J. (2017). Learning stagedependent effect of M1 disruption on value-based motor decisions. NeuroImage, 162, 173-185.
3. Vassiliadis, P., & Derosiere, G. (2020). Selecting and executing actions for rewards. The Journal of Neuroscience, 40(34), 6474-6476.
4. Alamia, A., Zénon, A., VanRullen, R., Duque, J., & Derosiere, G. (2019). Implicit visual cues tune oscillatory motor activity during decision-making. NeuroImage, 186, 424-436.
5. Derosiere, G., Klein, P. A., Nozaradan, S., Zénon, A., Mouraux, A., & Duque, J. (2018). Visuomotor correlates of conflict expectation in the context of motor decisions. The Journal of Neuroscience, 38(44), 9486-9504.
6. Derosiere, G., Thura, D., Cisek, P., & Duque, J. (2022). Hasty sensorimotor decisions rely on an overlap of broad and selective changes in motor activity. PLOS Biology, 20(4), e3001598


Invited by Olivier Manzoni

Monday, Septembre 11th at 11 am – Inmed conference room

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