Anterior insula regulates brain network transitions that gate conscious access

Conscious access to sensory information is likely gated at an intermediate site between primary sensory and transmodal association cortices, with the anterior insular cortex (AIC) playing a key role. Functional neuroimaging using a volitional mental imagery task in healthy volunteers, with propofol titrated to loss of behavioral responsiveness, showed that AIC dysfunction is associated with impaired transitions between default-mode and dorsal attention networks. Candidate subcortical regions such as the thalamus and basal forebrain did not show this association. In awake participants, pre-stimulus AIC activity near perceptual threshold predicted conscious access. These findings support the hypothesis that AIC regulates brain network transitions that gate conscious access.

Study at a glance

Abstract

Conscious access to sensory information is likely gated at an intermediate site between primary sensory and transmodal association cortices, but the structure responsible remains unknown. We perform functional neuroimaging to determine the neural correlates of conscious access using a volitional mental imagery task, a report paradigm not confounded by motor behavior. Titrating propofol to loss of behavioral responsiveness in healthy volunteers creates dysfunction of the anterior insular cortex (AIC) in association with an impairment of dynamic transitions of default-mode and dorsal attention networks. Candidate subcortical regions mediating sensory gating or arousal (thalamus, basal forebrain) fail to show this association. The gating role of the AIC is consistent with findings in awake participants, whose conscious access is predicted by pre-stimulus AIC activity near perceptual threshold. These data support the hypothesis that AIC, situated at an intermediate position of the cortical hierarchy, regulates brain network transitions that gate conscious access.