Consciousness and the Brain Stem

Suppose consciousness exists at a more fundamental level than the brain’s cortex. Swedish neuroscientist Bjorn Merker suggests that “primary consciousness,” which he regards as an ability to integrate sensations from the environment with one’s immediate goals and feelings in order to guide behavior, springs from the brain stem. “To be conscious is not necessarily to be self-conscious,” Merker says. “The tacit consensus concerning the cerebral cortex as the ‘organ of consciousness’ … may in fact be seriously in error.”

Merker bases his proposals on observations of cortically-deprived children with a condition known as hydranencephaly, the absence of most of the brain’s cortex. The children that he observed “recognized familiar adults, liked familiar settings, and preferred specific toys, tunes, or video programs. Although saddled with limited mobility, some kids took behavioral initiatives, such as learning to activate a toy by throwing a switch.”

He also built his theory on earlier work conducted by Canadian neurosurgeons Wilder Penfield and Herbert Jasper. Their work in removing large portions of cortex in the treatment of severe epilepsy helped isolate physiological bases for “absence epilepsy,” a sudden loss of consciousness, that indicated brain stem involvement in primary consciousness. Merket adds that animal research activity since that time confirms the brain stem’s involvement in primary consciousness.

He proposes that such a consciousness yields a two-dimensional view of the world with moving shapes. It also is able to respond emotionally in ways that are recognizably human, suggesting that the brain stem is more than a mere reptilian vestige. “The human brain stem is specifically human,” Merker says. “These children smile and laugh in the specifically human manner, which is different from that of our closest relatives among the apes.”

Link: Consciousness in the Raw

For more information: NINDS Hydranencephaly Information Page

One support group’s experiences and observations: Rays of Sunshine

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