The overnight study session: the quintessential way to cram your brain full of everything it needs to know just a few hours before the test. We’ve all experienced the high-anxiety exhaustion that accompanies sleepless studying, but does it actually help when it comes to memorization?

A recent study by researchers at Brandeis University, published in the journal eLife suggests that sleep is essential to memorization and therefore essential to the studying process. It has been long known that sleep, memory, and learning are intimately linked, and that sleep is essential for “memory consolidation,” the process by which short-term memory is converted into long-term. But the question still remains how.  

Up until now, two beliefs pervaded: Either memory consolidates during sleep because the lack of brain activity allows neurons to do their thing, or memory neurons actually cause us to sleep. Graduate students Bethany Christmann and Paula Haynes found in their research that the latter may actually prove true.

During their study, Haynes and Christmann used Drosophila melanogaster, or fruit flies, as their subjects, noting that a simpler brain structure would allow further insight into more complicated brain systems like our own. Focusing on the dorsal paired medial (DPM) neurons, a well-known site of memory consolidation, the two researchers were able to examine that flies actually slept more when DPM neurons were activated. When the neurons were at rest, the flies were fully awake, buzzing about as flies do.

This process was found to occur within an area of the fly’s brain known as the mushroom body, or the fly-equivalent of the human hippocampus, where memory is known to be stored. This section not only proved to be the site of memory and learning, but also the area that kept the flies awake. When memory convertors began to consolidate short-term memory to long-term, wakefulness was inhibited in the mushroom body.

“It’s almost as if that section of the mushroom body were saying, ‘Hey, stay awake and learn this,’” Christmann said. “Then, after a while, the DPM neurons start signaling to suppress that section, as if to say, ‘You’re going to need sleep if you want to remember this later.’”

Such information will prove extremely useful in the long run as we continue to unravel the mysteries of memory-sleep connection in ourselves. “Eventually, it could help us figure out how sleep or memory is affected when things go wrong, as in the case of insomnia or memory disorders,” Christmann said.  It could also help us score the coveted "A" on our next test, without ending the love affair between ourselves and our beds.

Source: Haynes PR, Christmann BL, Griffith LC. A single pair of neurons links sleep to memory consolidation in Drosophila melanogaster. eLife. 2015.