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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.

A stable relation between words and referent objects or events underlies human language. One of the most fundamental questions is how brain processes new words in order to form new lexical items. The answer to such questions will bring significant breakthrough in multiple fields, ranging from methods of language teaching and speech correction programs for children with late development to clinical rehabilitation of patients with speech impairments and neurophysiological functional tests of language network. This review presents the current state of Russian and foreign studies dedicated to new words learning in auditory modality. We tried to consider all varieties of techniques and paradigms in the field. Equal attention is paid both to studies of the phonological processing of a word (recognition of a phonetic pattern), and to works which consider the ways in which word acquire semantics. We discuss experiments carried out with an aid of such neuroimaging methods as fMRI, EEG / MEG, etc.

Large-scale cortical beta (β) oscillations have been implicated in the learning processes but their exact role is debated. We explored the dynamics of β-oscillations while 25 adult participants learned, through trial and error, novel associations between four auditory pseudowords and movements of four body extremities. We used MEG to evaluate learninginduced changes in beta modulation accompanying cue-triggered movements.Our findings showed that spatial-temporal characteristics of movement-related β-oscillations underwent a major transition as learning proceeded. Early in learning, suppression of β-power in multiple cortical areas occurred long before movement initiation and sustained throughout the whole behavioral trial. As learning advanced and task performance reached asymptote, βsuppression was replaced by a widespread and prolonged rise in β-power. The β-power rise started shortly after the initiation of correct motor response and mainly comprised the prefrontal and medial temporal regions of the left hemisphere. This post-decision β-power predicted trial-by-trial response times (RT) at both stages of learning (before and after the rules become familiar) but in opposite ways. When a subject started to acquire associative rules and gradually improved task performance, a decrease in RT was correlated with the increase in the post-decision β-band power. Repeatedly correct implementation of the learned rules reversed this correlation in the opposite direction with faster (more confident) responses associated with the weaker post-decision β-band 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.

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