Poster #: 64
Topic: Memory and perception
Wednesday, Sep 9, 2015
MEG/EEG evidence for prediction in the primary auditory cortex
1MEG & Cortical Networks, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
2Institute of Psychology, University of Leipzig, Leipzig, Germany
3Max Planck Institute for Emprial Aesthetics, Frankfurt, Germany
Active theories of perception posit that the brain exploits sensory inferences based on stimulus expectancies to best model the current state of affairs in the world. Brain’s responses to omitted, but highly expected stimuli, have been shown to resemble to a degree the response to the actual stimuli, suggesting activation of deputy sensory cortices. We used human EEG (Study 1, 17 participants) and MEG (Study 2, 20 participants) to test the extent of response “resemblance”, by directly comparing predictable vs. unpredictable deviant pure tones with their (rare) omissions. We observed nearly identical evoked responses to highly predictable stimuli and their omissions in the sensor space for EEG, and in the source space for MEG, locating the sources within the primary auditory cortices. Both responses were equally sensitive to an increase of the stimulus contrast: increase in magnitude of deviancy lead to an increase in evoked magnitude. Responses to unpredictable stimuli and their omissions differed significantly. We take this as evidence for a virtually perfect auditory prediction representation by our auditory cortices, overriding the concept of “stimulus template”, traditionally understood as an abstract or subsampled sensory representation.