Spatiotemporal patterns of oscillatory brain activity during auditory word recognition in children: A synthetic aperture magnetometry study

Abstract

Objective We studied the task-induced spatiotemporal evolution and characteristics of cortical neural oscillations in children during an auditory word recognition task. Methods We presented abstract nouns binaurally and recorded the MEG response in eight healthy right-handed children (6–12 years). We calculated the event-related changes in cortical oscillations using a beamformer spatial filter analysis technique (SAM), then transformed each subject's statistical maps into standard space and used these to make group statistical inferences. Results Across subjects, the cortical response to words could be divided into at least two phases: an initial event-related synchronization in both the right temporal (100–300 ms, 15–25 Hz; 200–400 ms, 5–15 Hz) and left frontal regions (200–400 ms; 15–25 Hz); followed by a strong left-lateralized event-related desynchronization in the left temporal region (500–700 ms; 5–15 Hz). Conclusions We found bilateral event-related synchronization followed by later left lateralized event-related desynchronization in language-related cortical areas. These data demonstrate the spatiotemporal time course of neural activation during an auditory word recognition task in a group of children. As well, this demonstrates the utility of SAM analyses to detect subtle sequential task-related neural activations.