Activity in part of the neural correlates of consciousness reflects integration.

Integration is often considered essential for generating conscious experiences, so brain activity linked to consciousness should increase when integration demands rise. Using fMRI and informational masking, researchers compared hearing simple repeating tones versus harmonic tone triplets to manipulate integration. The neural correlates of auditory consciousness included the superior temporal gyrus, lateral and medial frontal regions, cerebellum, and parietal cortex. Only left parietal cortex activity increased significantly with greater integration demands. Integration accounts for part of the neural activity underlying conscious experiences, but much of the associated brain activity likely reflects other processes.

Study at a glance

Abstract

Integration is commonly viewed as a key process for generating conscious experiences. Accordingly, there should be increased activity within the neural correlates of consciousness when demands on integration increase. We used fMRI and "informational masking" to isolate the neural correlates of consciousness and measured how the associated brain activity changed as a function of required integration. Integration was manipulated by comparing the experience of hearing simple reoccurring tones to hearing harmonic tone triplets. The neural correlates of auditory consciousness included superior temporal gyrus, lateral and medial frontal regions, cerebellum, and also parietal cortex. Critically, only activity in left parietal cortex increased significantly as a function of increasing demands on integration. We conclude that integration can explain part of the neural activity associated with the generation conscious experiences, but that much of associated brain activity apparently reflects other processes.