The transition to college requires students to become accustomed to many unfamiliar occurrences. Some of these transitions are expected, such as staying up late in order to finish a paper or to spend time with friends. Others are almost impossible to foresee, such as the strange scenarios that college hazing rituals bring about.
And then, there are some things that really aren’t that strange, but still take some time to get used to. For me, one of the most alien behaviors that I experienced was witnessing other people sleeping. Outside of college, when someone is tired, they go home and fall asleep in bed, away from the rest of the world. In college, people fall asleep everywhere: common rooms, the library, friend’s couches, etc. All of these places appear to be the perfect resting place for an exhausted student. Even if they do manage to make it back to their rooms, students often share the room with a roommate or two. And although there is nothing unfamiliar about sleeping, I often find myself surprised by how others sleep. Since coming to college, I have witnessed some pretty strange sleep occurrences. I have seen people sleeping in hallways, people talking in their sleep, and the most amusing by far, I have watched as people unknowingly twitch in their sleep.
Sleep is a vital part of all human life. Therefore, one of the biggest questions among scientists is; “why do we need sleep?” Currently there are many theories about the purpose of sleep. It is felt that sleep may have evolved to protect us, keeping us hidden from potential predators. Secondly, it is thought that sleep acts to repair damage that has occurred to the brain during the day. Researchers also believe that memories are solidified during sleep, transferring from short term to long term. Also, sleep is thought to be related to growth, as growth hormones are released during sleep (Myers, 2007).
Research suggests that sleeping may provide time for learning, especially among infants. As newborn infants are overwhelmed with new sights and sounds, sleep gives them time to explore and learn about themselves. This theory differs greatly from the original idea that twitches during REM sleep are caused by leaked signals slipping through to the motor cortex. Psychology professor Mark Blumberg feels that during sleep, the twitching of different parts of the body allows infants to determine what particular nerves do, and what response their activation will produce. By twitching, infants are able to “get to know” their bodies. Because people twitch most frequently during infancy, the study of infants may help to determine the purpose of twitching in all people, including college students.
Recent findings suggest that single neurons are responsible for individual muscles, so each neuronal connection must be learned individually in order for large-scale movements to occur (Petersson, Waldenström, Fåhraeus & Schouenborg, 2003). During sleep, infants are able to fire signals from individual neurons, allowing them to determine exactly what muscle is associated with that specific neuron.
Through this mechanism, infants are able to begin to understand their bodies. This knowledge does not only help them with coordination but also with responses to stimuli. In order to test this theory, Khazipov, et al (2004) set up situations in which infant rats received either the correct or the opposite feedback to their twitches during sleep. The “reverse-feedback” group received a puff of air on the left side of their tail when they twitched to the right, and a puff of air on the right side of their tail when they twitched to the left. After only a few hours of training it was found that the rats in the “reverse feedback” group exhibited strange responses when exposed to stimuli. For example, when the right side of their tails was touched with a hot laser, they often moved their tails towards instead of away from the heat source. These findings suggest that the twitches that occur during sleep are related to learning about the location and function of specific body parts. Humans appear to show a similar pattern, as it is found that the triggering of localized spindles that cause muscle twitches in in vivo rats are characteristic of the spindle bursts and movements of fetal humans. (Blumberg & Lucas, 1994)
You may be wondering, if these findings are correct, why do fully-grown humans still twitch in their sleep? Shouldn’t all of these connections be mapped by the time we reach adulthood? It is thought that the twitching that occurs during the REM sleep of adults’ acts to retain and refine the understanding of the body. As humans, and other sleeping organisms, age they twitch less in their sleep. This helps support the retention and refining theory, as less time is required to re-examine these neuronal connections, as it is to explore them for the first time.
So, the next time that you see an exhausted student sleeping in the library instead of studying, remember that they are still learning. With each involuntary twitch, they are reviewing and relearning all of the individual connections between neurons and muscles.
Blumberg, M. S., & Lucas, D. E. (1994). Dual mechanisms of twitching during sleep in neonatal rats. Behavioral Neuroscience, 108(6), 1196-1202.
Khazipov, R., Sirota, A., Leinekugel, X., Holmes, G. L., Ben-Ari, Y., & Buzsáki, G. (2004). Early motor activity drives spindle bursts in the developing somatosensory cortex. Nature, 432(7018), 758-761.
Myers, David G. (2007). Psychology. Holland, Michagan: Worth Publishers.
Petersson, P., Waldenström, A., Fåhraeus, C., & Schouenborg, J. (2003). Spontaneous muscle twitches during sleep guide spinal self-organization. Nature, 424(6944), 72-75. Retrieved from http://www.scopus.com
Dingfelder, Sadie F. (2006 January). To sleep, perchance to twitch. Monitor on Psychology, 37, Retrieved February 25, 2009, from http://www.apa.org/monitor/jan06/twitch.html