1 Abstract
Being able to anticipate events before they happen facilitates stimulus processing. The anticipation of the contents of events is thought to be implemented by the elicitation of prestimulus templates in sensory cortex. In contrast, the anticipation of the timing of events is typically associated with entrainment of neural oscillations. It is so far unknown whether temporal expectations interact with feature-based expectations, and, consequently, whether entrainment modulates the generation of content-specific sensory templates. In this study, we investigated the role of temporal expectations in a sensory discrimination task. We presented participants with rhythmically interleaved visual and auditory streams of relevant and irrelevant stimuli while measuring neural activity using magnetoencephalography. We found no evidence that rhythmic stimulation induced prestimulus feature templates. However, we did observe clear anticipatory rhythmic pre-activation of the relevant sensory cortices. This oscillatory activity peaked at behaviourally relevant, in-phase, intervals. Our results suggest that temporal expectations about stimulus features do not behave similarly to explicitly cued, non-rhythmic, expectations; yet elicit a distinct form of modality-specific pre-activation.
Significance Statement The brain extracts temporal regularities from the environment to anticipate upcoming events in time. Furthermore, if prior knowledge about the contents of upcoming events is available, the brain is thought to leverage this by instantiating anticipatory sensory templates. How and whether both types of predictions (regarding time and content) share common mechanisms is still unclear. We investigated if neural sensory templates occur in response to a rhythmic stimulus stream with predictable temporal structure, and whether these templates follow the rhythmic structure of the task. We found that temporal rhythmic predictions did not induce sensory templates, but rather modulated the excitability in early sensory cortices. We thereby shed light on the neural mechanisms underlying perception with multidimensional expectations.
Competing Interest Statement
The authors have declared no competing interest.