Time pressure boosts corticospinal excitability

Details

Supervisors

Duque, Julie ; Fievez, Fanny

Faculty

Faculté des sciences de la motricité

Degree label

Master [120] en sciences de la motricité, orientation éducation physique

Abstract

Decision-making is ubiquitous in our daily life. Each decision requires a compromise between speed and accuracy (SAT) in order to maximize the global reward rate. The aim of the present study was to investigate the impact of urgency on the decision-making process. 15 healthy participants realized a modified version of the ‘tokens task” in which, sensory evidence continuously evolves during a trial. They were confronted to 2 different types of block: one focusing on choice’s speed while the other emphasize choice’s accuracy. In this task, they had to choose between left or right by flexing the corresponding index. TMS was applied over M1 to allows us to observe changes in cortico-spinal activity (CSE), bilaterally in the hand’s muscles. Results: In the block with a higher urgency (speed block), the subjects responded sooner, less accurately and with a lower propensity for non-response. The CSE was increased in the unselected hand for the “speed” condition in comparison to the “accuracy” condition. There was also an increase of CSE over time but only in the unselected hand for the “speed” condition. We presumed that these results were caused by a global and nonspecific urgency signal which grows over time. We propose that this signal could come from the basal ganglia. Moreover, the non-significative result obtained in the selected hand could be explained by a selective inhibition for the action favored by the sensory evidence.