Expectation suppression across sensory modalitites: a MEG investigation

Abstract

In the last few decades, a lot of research focus has been to understand how the human brain generates expectation about the incoming sensory responses and how it deals with surprise or unpredictable input. It is evident in predictive processing literature that the human brain suppresses the neural responses to predictable/expected stimuli (termed as expectation suppression effect). This thesis provide evidence to how expectation suppression is affected by content-based expectations (what) and temporal uncertainty (when) across sensory modalities (visual and auditory) using state-of-art Magnetoencephalography (MEG) imaging. The result shows that visual domain is more sensitive to content-based expectations (what) more than the timing (when), also visual domain shows sensitivity to timing (when) only if what was predictable. However, Auditory domain is equally sensitive to what and when features, showing enhanced suppression to expectation compared to visual domain. This thesis concludes conclude that the sensory modalities deal differently with the contextual expectations and temporal predictability. This suggests that while investigating predictive processing in the human brain, the modality specific differences should be considered, since the predictive mechanism at work in one domain should not necessarily be generalized to other domains as well.