alpha blocking
the suppression of alpha waves that is observed in some individuals via electroencephalography (EEG) when they focus their eyes on an unexpected stimulus or perform an active mental task. It is sometimes taken as an indicator of orienting or attention. The notion of “alpha blocking” is inferential, however; what is actually observed is a drop in visible alpha-band activity in the “raw” scalp EEG. Typically, blocked alpha waves are replaced by faster, low-amplitude, irregular waveforms on the EEG, a phenomenon called desynchronization.