Bypassing use-dependent plasticity in the primary motor cortex to preserve adaptive behavior

M Bosc,G Bucchioni,T Michelet,B Ribot

doi:10.1038/s41598-021-91663-9

Abstract

Behavioral adaptation, a central feature of voluntary movement, is known to rely on top-down cognitive control. For example, the conflict-adaptation effect on tasks such as the Stroop task leads to better performance (e.g. shorter reaction time) for incongruent trials following an already incongruent one. The role of higher-order cortices in such between-trial adjustments is well documented, however, a specific involvement of the primary motor cortex (M1) has seldom been questioned. Here we studied changes in corticospinal excitability associated with the conflict-adaptation process. For this, we used single-pulse transcranial-magnetic stimulation (TMS) applied between two consecutive trials in an interference flanker task, while measuring motor-evoked potentials (MEPs) after agonistic and antagonistic voluntary movements. In agonist movement, MEP amplitude was modulated by recent movement history with an increase favoring movement repetition, but no significant change in MEP size was observed whether a previous trial was incongruent or congruent. Critically, for an antagonist movement, the relative size of MEPs following incongruent trials correlated positively with the strength of behavioral adaptation measured as the degree of RT shortening across subjects. This post-conflict increase in corticospinal excitability related to antagonist muscle recruitment could compensate for a potential deleterious bias due to recent movement history that favors the last executed action. Namely, it prepares the motor system to rapidly adapt to a changing and unpredictable context by equalizing the preparation for all possible motor responses.

Highlights

Behavioral adaptation, a central feature of voluntary movement, is known to rely on top-down cognitive control
A comparison of reaction time (RT) in the different trial conditions showed the previously observed impact of cognitive condition sequence on the conflict adaptation effect (i.e., longer RTs during cI compared to iI trials Fig. 2; see[4 ]: A three-way ANOVA of the RTs under the four cognitive conditions and the two sequence types—i.e., the movement history—showed main effect of cognitive condition on the RT (F(3,39) = 168.9; p < 0.01)
A significant interaction effect of cognitive condition × sequence (F(3, 39) = 10.8; p < 0.01) was observed. This was confirmed by post hoc comparison, which revealed that the conflict adaptation effect was present only for repetition trial RTs (593.3 ± 3.5 vs 570.3 ± 3.1; p < 0.0001) and not for the RTs of change trials (577.6 ± 3 vs 584.5 ± 3.1; p > 0.05; Fig. 2)

Summary

Introduction

Behavioral adaptation, a central feature of voluntary movement, is known to rely on top-down cognitive control. Even when we try to control our environment, unpredictable events or sudden changes are impossible to avoid and action decisions must be adjusted in order to reach our initial goal This adaptive capability is a central feature of voluntary (or goal-directed) behavior and is thought to rely on the cognitive or executive control function process[1]. One of the most studied models of behavioral adaptation that supports the existence of a cognitive control of action, along with post-error slowing[2], is so-called post-conflict behavioral adjustment This can be observed during the performance of an interference-task in which congruent (C trial) and incongruent (I trial) stimuli (Fig. 1A and Table 1) are successively presented to subjects instructed to elicit an immediate motor response. Based on the competition between potential actions that is known to occur within the motor s ystem[19,20], we hypothesized that this modulation

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Conclusion