Not getting enough sleep can certainly make a day less pleasant, but can one all-nighter really affect your brain functioning? To answer these kinds of questions, it is typically easier to start with a smaller subject, such as a zebrafish. Think back to the last time you had to pull an all-nighter; how was your memory the next day? Chances are, as you became more and more sleep-deprived, your memory started getting significantly worse than it would be with a full night of sleep. To answer basic questions such as how sleep deprivation affects memory, scientists took a step back from humans and turned their attention toward the zebrafish. As well as being a much more stable and predictable subject than humans, zebrafish are well known for being ideal models for neurobehavioral studies. Scientists utilized these models to test the impact of sleep-deprivation by designing an object discrimination paradigm for zebrafish with different degrees of sleep deprivation.
A group of researchers from Universidade Federal do Rio Grande do Norte designated four distinct sleep conditions for a cohort of zebrafish. The control condition allowed for the corresponding fish to sleep without experimenter-influence. The other three conditions included partial sleep deprivation, as well as total sleep deprivation through either pulses of light or prolonged light exposure. Following exposure to one of the sleep conditions, the fish were exposed to an object discrimination task. This involved placing them in an environment with two objects, one familiar and one unfamiliar; the assumption being that more aware fish would gravitate towards exploring a new object. What they found was a progressive decrease in the relative memory performance of the zebrafish with increasing severities of sleep deprivation. The control group of fully-rested fish were most likely to explore the new object in their environment, indicating clear discrimination between the two objects. The partially sleep-deprived group also explored the new object more than the familiar one, but to a lesser degree than the control group. In contrast, both of the total sleep deprivation groups showed no preference for the new object over the familiar one, indicating reduced levels of object discrimination. The researchers concluded that as little as one night of sleep deprivation can significantly affect the cognitive processes of zebrafish, given the reduced performance on object discrimination tasks.
These results may indicate a similar negative effect on cognitive processing in humans experiencing sleep-deprivation. Warranting future study, these results begin to discern how much sleep would be too little for the model being studied. Should future studies utilize the results or methods of this study, there may be opportunities to assess how significantly sleep deprivation can negatively impact cognitive performance.
Pinheiro-da-Silva, J., Silva, P. F., Nogueira, M. B., & Luchiari, A. C. (2017). Sleep deprivation effects on object discrimination task in zebrafish (Danio rerio). Animal Cognition, 20(2), 159-169. doi:10.1007/s10071-016-1034-x
Alaina Bandanza
October 12, 2017 — 4:54 pm
Love this article! Makes me think I should get to bed earlier!
Marissa Soto
October 16, 2018 — 4:33 am
This reminds me about the mallard ducks, and how the ducks on the outsides are half asleep to protect the deep sleeping ducks in the middle. When I read this section in the book, I wondered how the ducks that slept with one eye open were able to function the next day. Humans are very similar to animals, and I would think animals can be sleep deprived. Reading this experiment proved that point, and I am surprised the book in that very section did not mention even a little point about this because that was my main thought that wasn’t answered in the moment.