Neuromagnetic activity in alpha and beta bands re ̄ect learning-induced increases in coordinative stability

Objective: To investigate how learning induced increases in stability on a syncopation task are manifest in the dynamics of cortical activity. Method: Magnetoencephalography was recorded from 143 sensors (CTF Systems, Inc). A pre-training procedure determined the critical frequency (Fc) for each subject (n ˆ 4). Subjects either syncopated or synchronized to a metronome that increased in frequency from 1.2 to 3.0 Hz in 0.2 Hz steps. The Fc was the point at which subjects spontaneously switched from syncopation to synchronization. Subjects then underwent 100 training trials (with feedback) at Fc. Following the learning phase the pre-training procedure was repeated. Results: An increase in the Fc occurred indicating that practice improved the stability of syncopation. The transition delay was also observed in the phase of the time-averaged signal in sensors over the contralateral sensorimotor area and in power analysis in the 8±12 Hz and 18±24 Hz frequency bands. Initially, reduced power was observed bilaterally during syncopation compared to synchronization. Following training, these differences were reduced or eliminated. Conclusion: Pre-training power differences can be explained by the greater dif®culty of the syncopation task. The reduction in power differences following training suggests that at the cortical level, syncopation became more similar to synchronization possibly re ̄ecting a decrease in task and/or attention demands. q 2001 Elsevier Science Ireland Ltd. All rights reserved.