Abstract

Background: Circadian rhythms and inhibitory neurotransmission are fundamental regulators of sleep–wake cycles and the functional state of consciousness. Objective: To propose an integrative hypothesis linking environmental light exposure, Suprachiasmatic Nucleus (SCN) circadian timing, and gamma-aminobutyric acid (GABA) signaling in the modulation of sleep quality and conscious processing. Methods: Conceptual synthesis of evidence from circadian biology, retinal neurophysiology, and sleep neuroscience. Results: Light entrains the SCN, which coordinates circadian rhythms and modulates GABAergic inhibitory tone through defined neural and neuroendocrine pathways. Retinal GABA shapes visual signal processing without affecting optical refractive properties. Disruption of circadian alignment—through inadequate light exposure, nocturnal blue light, or chronic short sleep—reduces inhibitory control and promotes cortical hyperarousal. Conclusions: This model provides a mechanistic framework linking circadian timing and inhibitory neurotransmission to the quality of consciousness, with implications for sleep disorders and neuropsychiatric conditions.

Keywords

circadian rhythm, suprachiasmatic nucleus, gaba, neural inhibition, sleep deprivation, consciousness, light exposure, insomnia