They are confined to windowless cells roughly the size of a king bed for 23 hours a day, with virtually no human contact except for brief interactions with prison guards. According to scientists speaking at the conference session, this type of social isolation and sensory deprivation can have traumatic effects on the brain, many of which may be irreversible.
…For good or bad, the brain is shaped by its environment—and the social isolation and sensory deprivation King experienced likely changed his. Chronic stress damages the hippocampus, a brain area important for memory, spatial orientation and emotion regulation. As a result, socially isolated people experience memory loss, cognitive decline and depression. Studies show depression results in additional cell death in the hippocampus as well as the loss of a growth factor that has antidepressant-like properties, creating a vicious cycle. When sensory deprivation and an absence of natural light are thrown into the mix, people can experience psychosis and disruptions in the genes that control the body’s natural circadian rhythms.
…King has experienced lasting cognitive changes from his time in solitary confinement. His memory is impaired and he has lost his ability to navigate, both of which are signs of damage to the hippocampus. At one point he was unable to recognize faces, but that problem has passed.