Parietal gamma-band activity during auditory spatial precueing of motor responses

Magnetoencephalographic gamma-band activity (GBA) was used to investigate synchronization of cortical networks in putative auditory dorsal stream areas during the transformation of auditory spatial information into motor preparation. GBA was compared between lateralized vowels precueing either ipsi- or contralateral responses in two experiments with randomized versus blocked task presentation. In both studies, parietal GBA was higher for the contralateral than the ipsilateral precues. Spectral amplitudes at 54-64 Hz were maximal at 120 ms post precue onset during randomized presentations, while in the blocked task 62-72 Hz activity was present at precue onset and less peaked. These findings suggest a fast activation of parietal networks when auditory spatial precues are used to plan contralateral responses.