Event-related alpha desynchronization in touch - Comparing attention and perception

An event-related decrease in alpha power contralateral to the presentation of a stimulus is now a well-established phenomenon. Two distinct accounts of the functional role of alpha changes are present in the literature that either focus on alpha changes observed during attentional or simple perceptual tasks. This study directly compares tasks that invoke alpha decreases during exogenous, endogenous and perceptual processing. Using a data driven approach to compare alpha changes we show that alpha decreases differ only between exogenous and endogenous attention tasks for only a short time window, 500-600 ms after cue onset. We suggest this indicates a role for alpha in voluntary orientating and stimulus predictability.