Thomas J. Baumgarten, Ph.D | Effects of intrinsic and extrinsic neural activity changes on stimulus processing and perception

It is generally understood that the perception of a stimulus is mediated by a cascade of neural responses. Historically, the dominant approach in perceptual neuroscience was to record neural activity changes in response to the presentation of a target stimulus. These changes were then interpreted both as a direct consequence of the target stimulus and as a correlate of its perception. More recent approaches, however, have highlighted that neural activity changes happening before target stimulus presentation critically influence target stimulus processing and perception. Such “pre-(target) stimulus” effects differ with regard to the specific information they hold about the target stimulus. On the one hand, neural activity changes can result from intrinsic spontaneous fluctuations of neural activity, giving rise to brain states that are more or less beneficial for target stimulus processing and perception. In this case, the perceptual fate of the target stimulus is determined by the brain’s intrinsic regime and does not systematically depend on sensory information presented before the target stimulus. Alternatively, neural activity can be influenced extrinsically by sensory information presented before the target stimulus. If this prior information is systematically linked to the target stimulus, the corresponding extrinsic neural activity changes can hold predictive information about the target stimulus itself. In my talk, I will present exemplary findings of both intrinsic and extrinsic changes of “pre-(target) stimulus” neural activity from MEG studies focusing on the somatosensory and auditory domain. These results will demonstrate how the brain actively shapes our perception and how different facets of this generative process can be experimentally assessed.