Alpha synchronization during auditory spatial short-term memory.

Recent studies have suggested an active role of cortical alpha oscillations for cognitive functions including short-term memory. We used magnetoencephalography to assess alpha activity during an auditory spatial delayed matching-to-sample task compared with a nonmemory control condition. In the memory task, participants had to memorize the lateralization angle of a noise stimulus S1 and compare it with another lateralized sound S2 presented after an 800-ms delay phase. Whereas alpha desynchronization following S1 was observed over superior temporal areas under both conditions, only the memory task was accompanied by posterior parietal alpha synchronization during the subsequent delay period. The findings are consistent with the notion of alpha activity reflecting active inhibition of interfering processes during memory maintenance of spatial sounds.