The ancient Egyptians believed that the center of consciousness was in the heart. Modern humans believed it was in the neocortex.
"Neuroscientist Björn Merker has argued that the capacity for awareness in humans depends on structures in the midbrain alone."
"…the core of human consciousness is not our impressive neocortex, but our much more primitive midbrain. This simple structure synthesizes sensory data into a unified, egocentric point of view that lets us navigate our world. Insects, Barron and Klein now argue, have midbrain-like structures, including a “central complex,” that seem to allow bugs to similarly model themselves as they move through space."
"Midbrain Pons Medulla oblongata (Sometimes, the diencephalon is also considered part of the brainstem.) Together, these three parts work to regulate various involuntary functions, such as breathing, heart rate, and blood pressure. Your brainstem also plays a critical role in sleep and consciousness."