Date of Award

January 2014

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Hal Blumenfeld

Subject Area(s)

Medicine, Neurosciences

Abstract

Many studies exist which attempt to identify and elucidate precisely what constitutes the neural mechanisms of consciousness. From these, the precise relationship between attention and awareness as they relate to consciousness has been investigated with various theories emerging regarding the anatomical origin and temporal progression of neuronal activity when a subject perceives a stimulus and reports having consciously perceived said stimulus. Studies have identified the crucial role that attention plays in enhancing conscious perception of a stimulus. To date, the majority of research has focused on subjects being challenged with only an individual sensory modality, be it solely, visual or auditory. Fewer still have sought to study conscious report by subjects challenged across multiple sensory modalities. My research focused on investigating possible behavioral paradigms that allowed for the reliable study of conscious report when subjects are challenged with both visual and auditory stimuli. This particular paradigm was stimulus-driven, goal-directed and validated across each modality. Behavioral data was gathered from 11 subjects who were cued to either visual or auditory stimuli, which were calibrated to near threshold levels of perception. Following presentation of the stimulus, they were forced to identify and report both the location of the stimulus as well as their subjective perception of said stimulus. Initial data suggests, that conscious report of the location of perceived stimuli was significantly higher (96% visual, 83% auditory) compared to the location accuracy of non-perceived stimuli, which were at near chance levels (54% visual, 51% auditory; p<0.001). Additional differences in the role of attention modulation of perception between both modalities also emerged, with conscious visual perception being reported more often with visual cuing versus without visual cuing for the visual tasks; but no such relationship was observed with the auditory task.

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