Sleep, Dreams, and MemoryRobert Stickgold, Ph.D., is an assistant professor of psychiatry at the Harvard Medical School. Dr. Stickgold's work focuses on the nature and function of sleep and dreams within a cognitive neuroscience framework, with an emphasis on the role of sleep and dreams in memory consolidation and integration.
Taking an "unabashedly" neuro-scientific approach, Dr. Stickgold ponders the function of dreaming from the perspective of memory. Contrary to the historical view that the brain essentially shuts down during sleep, Dr, Stickgold states that the brain has, in fact, evolutionarily evolved to remain highly active during this period. "When everything seems to be shut off, there's all this complex machinery in action," says Dr. Stickgold. By studying EEG (Electroencephalograph) patterns, it becomes clear that sleep is divided into 90-minute periods, each revealing different brain activity and eye movement.
In terms of memory-related functions, sleep seems to cause procedural memories "to become consolidated and, in fact, stronger so we can perform faster," thus enhancing motor skills learned during the previous day. Studies reveal a marked improvement for tasks involving reaction time, as well as for such erudite domains as mathematical insight, following a good night's rest. Researchers studying the function of dreams have discovered that the mind replays and rehearses many of the movements experienced during motor learning. Furthermore, the brain makes associations between related types of movements, fitting new experiences in with previous memories and knowledge. Dreaming, states Dr. Stickgold, is one of most sophisticated of cognitive functions.
