The claustrum, a thin sheet of grey matter next to the insular cortex, was proposed by Crick and Koch in 2005 as possibly involved in consciousness. This review examines theories of consciousness and evaluates experimental evidence since 2005 to see if it supports or contradicts that hypothesis. It also suggests how future experiments could clarify how consciousness arises from neural activity and the claustrum's role.
People vary widely in their experiences during non-ordinary states of consciousness, and this variation is linked to measurable differences in the autonomic nervous system. The study shows that subjective experiences—such as changes in perception, emotion, or sense of self—correspond with distinct patterns of physiological responses, like heart rate or skin conductance. These findings suggest that the body's nervous system plays a key role in shaping how individuals experience altered states, highlighting a direct connection between inner, subjective phenomena and physiological processes.
This paper presents a biphasic relational framework for understanding the evolution of human consciousness, arguing that consciousness developed through two distinct phases: an initial phase focused on basic relational awareness and a later phase involving higher-order cognitive and social capacities. The authors propose that early hominid consciousness emerged from embodied interactions with the environment, while modern human consciousness required the evolution of complex social structures and symbolic thought. The approach integrates insights from evolutionary biology, neuroscience, and philosophy to suggest that consciousness is not a single phenomenon but a layered process shaped by relational dynamics across evolutionary time.