cellular culprit in scarring Scientists decipher brain ’ s noise

By directly recording electrical activity from the human brain, neuroscientists at the School of Medicine have shown that distinct, distant groups of brain areas that support memory retrieval act in concert, even during sleep. The findings, described in a study published online April 8 in Neuron, confirm for the first time that specific electrical patterns of coordinated neural activity in widely separated human brain structures during memory retrieval persist throughout our cycles of waking and sleeping. The findings confirm indirect observations made in previous studies that used brain imaging. They also shed light on why the brain paradoxically appears to exhaust so much of the body’s energy in what, at first glance, seems akin to the idling of a car’s engine. The human brain is a greedy organ. Accounting for only 2 percent of the body’s weight, it consumes 20 percent of the body’s energy. Yet the rate at which the brain gobbles glucose (the fuel our brain cells run on) barely budges when we cease performing a physical or mental activity. Even at rest, the brain seems engaged in a blizzard of electrical activity, which neuroscientists have historically viewed as useless “noise.” “Increases in brain activity during conscious thoughts and actions represent only the tip of the iceberg,” said Josef Parvizi, MD, PhD, associate professor of neurology and neurological sciences and the senior author of the Neuron study. “The vast amount of energy consumption by our brain is due to its spontaneous activity at all times when we are not consciously involved in a specific task.” What, then, is all this spontaneous noise for?