title: α oscillations related to anticipatory attention follow temporal expectations.
abstract: Temporal expectations have been shown to enhance visual analysis of task-relevant events, especially when these are coupled with spatial expectations. Oscillatory brain activity, particularly in the alpha band, has been implicated in regulating excitability in visual areas as a function of anticipatory spatial attention. Here we asked whether temporal expectations derived from regular, rhythmic events can modulate ongoing oscillatory alpha-band activity, so that the changes in cortical excitability are focused over the time intervals at which target events are expected. The task we used involved making a perceptual discrimination about a small target stimulus that reappeared from "behind" a peripheral occluding band. Temporal expectations were manipulated by the regular, rhythmic versus irregular, arrhythmic approach of the stimulus toward the occluding band. Alpha-band activity was measured during the occlusion period, in which no stimulus was presented, but target reappearance was anticipated in conditions of high versus low temporal expectation. Time-frequency analysis showed that the amplitude of alpha-desynchronization followed the time course of temporal expectations. Alpha desynchronization increased rhythmically, peaking just before the expected reappearance of target times. Analysis of the event-related potentials evoked by the subsequent target stimuli showed enhancement of processing at both visual and motor stages. Our findings support a role for oscillations in regulating cortical excitability and suggest a plausible mechanism for biasing perception and action by temporal expectations.
authors: Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, United Kingdom. gustavo.rohenkohl@psy.ox.ac.uk
authors: Gustavo
authors: G
authors: Rohenkohl
authors: Anna C
authors: AC
authors: Nobre
mesh_terms: D000328:Adult; D000513:Alpha Rhythm / Q000502:physiology*; D059031:Anticipation, Psychological / Q000502:physiology*; D001288:Attention / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D013998:Time Perception / Q000502:physiology*; D055815:Young Adult