51�Թ�

The second area—cumbersomely dubbed the ventrolateral part of the ventromedial hypothalamus, or VMHvl—is associated with aggression.

Specifically, the improved emotion regulation ability following the training was associated with changes in activation of a region of the brain called the ventrolateral prefrontal cortex.

Scientists now have concrete evidence that two groups of cells—the ventrolateral preoptic nucleus in the hypothalamus and the parafacial zone in the brain stem—are involved in prompting SWS.

The results showed that elderly people and Alzheimer's patients have a substantial decline in what are called ventrolateral preoptic neurons, and that loss of these brain cells is associated with sleep problems.

"These findings provide the first evidence that the ventrolateral preoptic nucleus in humans probably plays a key role in causing sleep, and functions in a similar way to other species that have been studied," Saper said.