J. O’Reilly: The representation, use and updating of priors in the human brain

Abstract
Perception does not simply reproduce the stimuli that reach our eyes and ears, but is heavily influenced by expectations, sometimes called ‘prior beliefs’ or simply ‘priors’. The extent to which we use these priors depends on the precision of both the prior, and of sensory evidence – when we are confident about what we see, the role of expectations is low, but when we are uncertain about sensory evidence, we fall back on expectations. In this seminar I will present MEG work investigating the neural basis of prior beliefs in a spatial orienting task (Marshall et al 2024, https://doi.org/10.1371/journal.pbio.3002383) – how are priors stored in the brain, and how are they integrated with incoming sensory evidence? Using a ‘rapid frequency tagging’ technique, we show that prior beliefs can be stored in an activity-silent manner as changes in the gain on sensory inputs to posterior parietal cortex. Leading on from this work, I will also present EEG studies investigating 1) the mechanisms by which prior beliefs are updated - particularly the role of beta oscillations and 2) mechanisms controlling the precision of sensory representations in early visual cortex. As a bonus I will discuss pupillometry correlates of the EEG effects.
May 28, 2025 at 5 pm

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Zoom Link:
https://tu-dresden.zoom-x.de/j/64644554045?pwd=243hE7GGzDTSKmILhaJ968g8uPDCGs.1
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