Could consciousness begin deep in the brain? Researchers make the case
Close your eyes and cover your ears. Much of the world around you disappears from view and hearing, yet your sense of being present, of being conscious, remains. What creates that basic feeling of being "you"?
A hypothesis published in the scientific journal The Neuroscientist proposes that consciousness may originate deep within the brainstem rather than in the cerebral cortex. Professor Marshall Devor of the Hebrew University of Jerusalem and Dr. Mark Baron of Hebrew University and Harvard Medical School argue that the basic capacity for conscious experience, particularly of pain, arises from primitive brainstem circuitry.
This theory challenges the prevailing view that consciousness primarily stems from the cerebral cortex, which is responsible for complex functions like language and planning. The researchers cite evidence from brain stimulation, epileptic seizures, and neurological injuries to support their claim that the feeling of pain does not depend on the cortex in the same way as complex sensory experiences do.
They point out that extensive cortical damage usually leaves pain intact, while such damage can severely degrade vision and hearing. Furthermore, they suggest that loss of consciousness is rare, while damage to specific brainstem regions consistently causes coma. The theory proposes that the brainstem not only keeps the cortex awake but also generates the basic capacity for conscious experience of pain and other senses.
It distinguishes between information processed robotically by the cortex and the feeling of consciously experiencing that information. The cortex handles sophisticated processing and evaluation of potential benefits or dangers, while the brainstem determines which sensory streams should enter conscious experience. This framework could explain why damage to specific cortical regions can impair certain abilities without eliminating basic awareness.
The authors also suggest an evolutionary explanation, proposing that the capacity for experiencing pain evolved early in the development of the brain and predates the more complex cortical processing. They highlight the mesopontine tegmentum in the brainstem as a potential area for further investigation to test this theory. While the precise mechanism remains unresolved, the paper proposes a framework for further research into the brainstem's role in generating consciousness.
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