These findings, reported in the June 30, 2005, issue of the journal Neuroscience and currently published on-line, might help to explain why children infants, in particular require much more sleep than adults, and also suggest a role for sleep in the rehabilitation of stroke patients and other individuals who have suffered brain injuries.

"Our previous studies demonstrated that a period of sleep could help people improve their performance of 'memory tasks,' such as playing piano scales," explains the study's lead author Matthew Walker, PhD, director of BIDMC's Sleep and Neuroimaging Laboratory. "But we didn't know exactly how or why this was happening.

"In this new research, by using functional magnetic resonance imaging (fMRI), we can actually see which parts of the brain are active and which are inactive while subjects are being tested, enabling us to better understand the role of sleep to memory and learning."

New memories are formed within the brain when a person engages with information to be learned (for example, memorizing a list of words or mastering a piano concerto). However, these memories are initially quite vulnerable; in order to "stick" they must be solidified and improved. This process of "memory consolidation" occurs when connections between brain cells as well as between different brain regions are strengthened, and for many years was believed to develop merely as a passage of time. More recently, however, it has been demonstrated that time spent asleep also plays a key role in preserving memory.

In this new study, twelve healthy, college-aged individuals were taught a sequence of skilled finger movements, similar to playing a piano scale. After a 12- hour period of either wake or sleep, respectively, the subjects were tested o
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Contact: Bonnie Prescott
bprescot@bidmc.harvard.edu
617-667-7306
Beth Israel Deaconess Medical Center
28-Jun-2005