Characterizing Cortical Visual Responses Near the Perceptual Threshold
Date
2022
Authors
Weibezahn, Annie
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Publisher
University of Oregon
Abstract
At any given moment, our brain is processing a large amount of sensory information, yet we are only consciously aware of a small portion of it. Information that we perceive must reach a perceptual threshold, which is defined as the point at which a subject can consciously recognize a presented stimulus 50% of the time. However, perceptual thresholds are not static - they vary from day to day and over the course of experimental tasks. Previous research at the single-cell level has suggested that our sensory perception strongly depends on the brain’s internal dynamics, often referred to as behavioral state, which changes based on factors like locomotion, arousal, and attention. Yet, whether behavioral states can account for fluctuations within perceptual thresholds is not known. The goal of my project was to characterize the dynamic range of population level neural responses to visual stimuli that varied in contrast and duration. Using wide field calcium imaging of transgenic mice, I identified maximum and minimum neural responses, quantified the population-level neural threshold, compared these values across cortical visual areas, and identified stimulus parameter values that likely lie near the perceptual threshold. In future work, pupil diameter and running speed will be tracked alongside neural activity in response to the near-threshold stimulus parameters I identified to further our understanding of how behavioral state influences conscious awareness.
Description
Keywords
perceptual threshold, behavioral state, consciousness