| Summary: | Time is an essential dimension of our experience, framing human behaviour at scales ranging from the millisecond organization of motor actions to circadian rhythms cycle, and beyond. Nevertheless, the mechanisms by which the brain keeps time and uses temporal information to organise behaviour remain unknown. Whereas the principles of the organisation of spatial cognition in the human brain are emerging, the same is not true for temporal cognition. The current study tested the influence of temporal expectations on attentional orienting to moving targets. In this task, a ball appeared at the left side of a screen and moved across the screen in steps following either a regular or irregular rhythm. After reaching an occluding band, the ball was temporarily occluded. When the ball reappeared, it contained either an upright (50%) or tilted (50%) cross. The task involved making a speeded perceptual discrimination about the target stimulus that reappears after the occlusion. The results indicated a strong behaviour benefit from temporal orienting. We recorded ERPs elicited by reappearance of the target stimulus, and investigated how temporal expectations influenced perceptual (e.g., visual P1 potential) and motor (lateralised readiness potential) stages of neural processing. The results showed that temporal expectations facilitated both early visual (P1) as well as motor (LRP) potentials. We are currently comparing induced frequency activity during the pre-occlusion and occlusion periods to look for modulation of rhythmic activity in lower frequency bands related to visual (alpha) and motor (mu) processing.
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