Entrainment decreases peak amplitude, but increases autocorrelation, in the auditory evoked response to target tones

摘要

Cognitive systems alter behavior in response to environmental events. We investigated the neurophysiological basis of one such effect, simple reaction time facilitation following temporally cued auditory target onsets. Participants responded to targets following 0, 2 or 3 warning tones presented at a constant ISI. Target onset could be predicted from the temporal pattern of warning tones. 306-channel MEG data were analyzed with multidipole source modeling; the dynamics of each source was estimated between 100ms prior and 500ms after target onset. The peak amplitude and latency of responses in auditory cortex were analyzed with 3 (entrainment) × 2 (hemisphere) ANOVAs, which revealed an entrainment by hemisphere interaction for amplitude, but no significant effect of entrainment on latency. The autocorrelation functions of each source revealed increasingly auto-correlated responses with increasing entrainment. Cross-correlation functions for each pair of auditory dipoles revealed, for four of the seven participants, increasing cross-correlation between left and right hemispheres with increasing entrainment. Results are discussed in terms of Attending Rhythm Theory [1] and Scalar Expectancy Theory [2].