A new study from the University of Pennsylvania shows that researchers have discovered the part of the brain — and furthermore, the neurochemical basis — for sleep deprivation’s effects on memory.
I spoke with researcher Dr. Ted Abel about his findings.
His research is published in the May 11th edition of The Journal of Neuroscience. Below is an excerpt of our conversation.
SP: Why is the study so important? What were your findings?
What we were trying to do was understand the impact sleep deprivation has on memory. We were studying relatively short periods of sleep deprivation in mice, the equivalent of half of a night of sleep loss. What our study showed was that even losing just five or six hours of sleep a night is enough to cause memory deficits.
SP: What are glia cells? What do they do?
Glia means glue. Over the years, people have thought glia cells were basically there to hold the brain together. What’s emerged over the past 10 to 15 years is that these glia cells are as active as neurons. The glia cells support the ongoing functioning of the brain, in addition to the central nervous system.
SP: Does this have the same effect for humans? For instance, if you get less than five hours of sleep, will it affect your memory?
What we found was that in normal mice, we were preventing the mice from sleeping about half the time. That would be four hours of sleep deprivation. In normal mice, we found that sleep deprivation impaired the mice’s memory. It might suggest that there are people in the human population that are better able to handle sleep deprivation. They don’t have as much of a cognitive defect, and they don’t lose attention or memory. Perhaps their glial cells and their ability to handle high levels of adenosine receptions are different, and more distinctive than the general population. But our study doesn’t address that.
SP: How did this affect sleep deprivation in the mice?
How it worked was that we trained animals in a task, and then deprived them of sleep. We tested them the next day on their ability to remember what happened during that training session. The mice had to explore objects and then we moved an object to a novel location. Normally, mice will explore a newly moved object. The mice that were sleep deprived were not able to recognize which object had been moved. So that reflects damage, or impairment in a specific memory system called the hippocampal memory system. In rodents, the memory system is for context and spatial arrangement of objects and the environment. In humans, the hippocampal memory system is the memory for people, places, and things. This would suggest that sleep deprivation would impair our ability to remember things we had experienced.
SP: What kinds of studies would you like to do in the future?
We’d like to actually look at other aspects of sleep deprivation, and see if they’re similarly regulated by glia cells. We didn’t have a chance to look at other aspects of sleep deprivation, such as metabolism. People tend to eat more when they are sleep deprived, and it would be fascinating for future studies to look at that.
Image: Ted Abel/University of Pennsylvania
Related link: As brain pathways deteriorate, so does our memory