The claustrum's proposed role in consciousness is supported by the effect and target localization of Salvia divinorum.
Frontiers in integrative neuroscience – January 01, 2014
Source: PubMed
Summary
The brain's claustrum, a thin sheet of neurons, shows a remarkable density of κ-opioid receptors. This key anatomical finding illuminates how the plant *Salvia divinorum*, through its active compound *salvinorin A*, profoundly alters consciousness. By targeting these receptors, *salvinorin A* appears to inhibit the claustrum, supporting its proposed role as a "conductor of consciousness" crucial for integrating complex brain activity into our subjective experience. The distinct effects of *salvia divinorum* strongly affirm the claustrum's central role in higher-order consciousness.
Abstract
THIS ARTICLE BRINGS TOGETHER THREE FINDINGS AND IDEAS RELEVANT FOR THE UNDERSTANDING OF HUMAN CONSCIOUSNESS: (I) Crick's and Koch's theory that the claustrum is a "conductor of consciousness" crucial for subjective conscious experience. (II) Subjective reports of the consciousness-altering effects the plant Salvia divinorum, whose primary active ingredient is salvinorin A, a κ-opioid receptor agonist. (III) The high density of κ-opioid receptors in the claustrum. Fact III suggests that the consciousness-altering effects of S. divinorum/salvinorin A (II) are due to a κ-opioid receptor mediated inhibition of primarily the claustrum and, additionally, the deep layers of the cortex, mainly in prefrontal areas. Consistent with Crick and Koch's theory that the claustrum plays a key role in consciousness (I), the subjective effects of S. divinorum indicate that salvia disrupts certain facets of consciousness much more than the largely serotonergic hallucinogen lysergic acid diethylamide (LSD). Based on this data and on the relevant literature, we suggest that the claustrum does indeed serve as a conductor for certain aspects of higher-order integration of brain activity, while integration of auditory and visual signals relies more on coordination by other areas including parietal cortex and the pulvinar.