Abstract:

The present study was aimed at investigating the connection between spatially separated brain regions, as well as the changes of the connection in time and frequency domain. Self-paced finger press related magnetoencephalography signals were recorded and analyzed by means of coherence analysis.And coherence coefficient of two signals corresponding to different cortical areas was calculated. Time frequency analysis was also used to discuss the cortical connection changes co-vary closely with time over the course of motor task in the three frequency band-α(5-15Hz)、β(16-25Hz) and low γ(30-45Hz). The results showed that channels with the most significant coherence relative to the selected reference channel were approximately in the same area, and with the increase of frequency band both the coherence coefficient and the coupled area declined. Moreover, the coherence coefficient changed covaried with time in the three frequency band. Then it is infered that there are different neuronal modulations in the contralateral motor cortex, and this modulation co-varies with time, which consequently reflects the changes of correlation between different brain regions in time and frequency domain.
 

Key words: magnetoencephalography; movement; coherence; time frequency analysis