When does consciousness arise? A subcortical model of its origins.
Brain structure & function April 28, 2026 Saúl Sal-Sarria, Mark Solms, Oliver H Turnbull
The origins of consciousness may lie not in the cerebral cortex but in ancient subcortical systems responsible for affective experience, particularly the ascending arousal networks of the upper brainstem and the periaqueductal gray. These structures sustain wakefulness and imbue it with valence, positioning consciousness as an embodied biological function grounded in feeling rather than higher cognition. From a developmental perspective, these subcortical structures mature relatively early in gestation, suggesting that a primitive form of subjective feeling may emerge during the third trimester, before cortical maturation. This view has ethical implications for debates on fetal pain perception, neonatal care, and treatment of individuals with profound cognitive impairment.