"The parts of the brain deteriorating earliest are the same regions that give us deep sleep," said article lead author Mander, a postdoctoral researcher in Walker's Sleep and Neuroimaging Laboratory at UC Berkeley. Aging typically brings on a decline in deep non-rapid eye movement (NREM) or "slow wave sleep," and the characteristic brain waves associated with it, including both slow waves and faster bursts of brain waves known as "sleep spindles." Youthful, healthy slow waves and spindles help transfer memories and information from the hippocampus, which provides the brain's short-term storage, to the prefrontal cortex, which consolidates the information, acting as the brain's long-term storage. "Sadly, both these types of sleep brain waves diminish markedly as we grow old, and we are now discovering that this sleep decline is related to memory decline in later life," said Winer, a doctoral student in Walker's lab. Another deficiency in later life is the inability to regulate neurochemicals that stabilize our sleep and help us transition from sleep to waking states. These neurochemicals include galanin, which promotes sleep, and orexin, which promotes wakefulness. A disruption to the sleep-wake rhythm commonly leaves older adults fatigued during the day but frustratingly restless at night, Mander said. Of course, not everyone is vulnerable to sleep changes in later life: "Just as some people age more successfully than others, some people sleep better than others as they get older, and that's another line of research we'll be exploring," Mander said. Meanwhile, non-pharmaceutical interventions are being explored to boost the quality of sleep, such as electrical stimulation to amplify brain waves during sleep and acoustic tones that act like a metronome to slow brain rhythms. - www.eurekalert.org