Sleeping may have more benefits than just health: it may actually improve your grades.

A new study by a MIT professor published last week in the journal Neuron suggests that sleeping rats exhibit brain activity that may resemble human dreams. This discovery may shed light on the link in humans between dreams and memory.

Although scientific studies in the past have shown a link between dream-filled sleep and memory formation, this is the first time scientists have caught a living brain in the act of reviewing the day's events.

Scientists say this study is the first step in the quest to find out why we dream and how important sleep is for the formation of stable memories.

"One of the possibilities is that in these sleep and dream states, we are reevaluating past experience" says MIT Associate Professor of Brain and Cognitive Sciences Matthew A. Wilson, who was the lead author of the study.

"The larger research program is looking at how different parts of the brain participate in memory," he says. "Sleep is part of that process."

Rat Race

Wilson and his team implanted sensors in the hippocampus of rats, the part of the brain that is responsible for short-term memory in both rats and humans. The team tracked the activity of a dozen to a few dozen of the neurons in the hippocampus--only a tiny fraction of the cells in that part of the brain.