Learning of new associations invokes a major change in modulations of cortical beta oscillations in human adults

Abstract

Large-scale cortical beta (β) oscillations were implicated in the learning processes, but their exact role is debated. We used MEG to explore the dynamics of movement-related βoscillations while 22 adults learned, through trial and error, novel associations between four auditory pseudowords and movements of four limbs. As learning proceeded, spatial-temporal characteristics of βoscillations accompanying cue-triggered movements underwent a major transition. Early in learning, widespread suppression of βpower occurred long before movement initiation and sustained throughout the whole behavioral trial. When learning advanced and performance reached asymptote, βsuppression after the initiation of correct motor response was replaced by a rise in βpower mainly in the prefrontal and medial temporal regions of the left hemisphere. This post-decision βpower predicted trial-by-trial response times (RT) at both stages of learning (before and after the rules become familiar), but with different signs of interaction. When a subject just started to acquire associative rules and gradually improved task performance, a decrease in RT correlated with the increase in the post-decision βband power. When the participants implemented the already acquired rules, faster (more confident) responses were associated with the weaker post-decision βband synchronization. Our findings suggest that maximal beta activity is pertinent to a distinct stage of learning and may serve to strengthen the newly learned association in a distributed memory network.

Neural mechanisms of associative cortical plasticity in cognitive domain: Magnetoencephalographic studies

“…This effect comprised a typical beta-rebound in the sensorimotor regions and a significant surge in beta activity in various associative cortical regions. We postulate that these beta oscillations constitute a reverberation mechanism that reinforces the associative connection and guards it against potential interference [3].…”

“…Этот эффект включал в себя не только обычную бета-синхронизацию в сенсомоторных областях коры после движения, но и резкое увеличение мощности бета-колебаний во множестве ассоциативных областей коры. Мы полагаем, что такие бета-осцилляции представляют собой реверберационный механизм закрепления ассоциативной связи и защиты её от помех [3]. В дальнейших экспериментах мы расширили процедуру, и проводили процедуру обучения на протяжении двух последовательных дней, с ночным сном между двумя записями.…”