A close association between consciousness and physiological regulation raises new questions about the role of the brainstem – the set of nuclei lying between the deepest parts of the cerebral hemispheres and the spinal cord. Typically, the brainstem has been thought of as an ‘enabling factor’ for consciousness, much like a power cable is an enabling factor for a TV. But the brainstem plays a highly active role in physiological regulation, leading some to suggest that this is where consciousness arises – with no need for cortex
