New research series: why we sleep

Research Findings and Resources

Two studies in mice by the National Institute of Mental Health show that we sleep so we can learn. The results of the two studies indicate that sleep organizes and streamlines connections in our brains, making them more efficient, by “downsizing” unneeded connections. As a result, scientists now believe that sleep helps us to make room for more learning.

One of the two studies was at the University of Wisconsin-Madison. Using an electron microscope, researchers were able to view the brains of mice, which show that synapses grow strong during daytime stimulation while at night they shrink by almost 20% during sleep. When we are awake, the pathways in our brains grow as we continuously learn and develop new memories. To balance this growth and make room, when we sleep these synapses weaken and shrink (de Vivo et al., 2017).

The second study was conducted at Johns Hopkins University School of Medicine, strengthening the evidence that a purpose of sleep is to “recalibrate” the brain cells used for learning and memories so we can deepen our learning and remove unneeded information. Scientists think that synapses are strengthened during the day and tend to lose capacity to convey information, negatively impacting learning and memory (Diering et al., 2017).

Implications for Mental Health

Though there is still a lot we don’t know about how sleep works and why we need to sleep, these two studies demonstrate the physiological, emotional and relational importance of sleep. Regularly assessing how someone is sleeping may help healthcare practitioners develop appropriate interventions. It may be helpful to ask about a person’s nighttime routines, if he/she keeps regular sleep patterns and feels rested in the morning. Knowing that sleep directly impacts learning may also point to why a client may be having difficulty implementing a skill or paying attention during a session. Coordinating effectively with primary care providers about sleep needs may help a patient to engage in his/her mental health improvement process.

Resources and References

de Vivo, L., Bellesi, M., Marshall, W., Bushong, E. A., Ellisman, M. H., Tononi, G., & Cirelli, C. (2017). Ultrastructural evidence for synaptic scaling across the wake/sleep cycle. Science (New York, N.Y.), 355(6324), 507-510. doi:10.1126/science.aah5982

Diering, G. H., Nirujogi, R. S., Roth, R. H., Worley, P. F., Pandey, A., & Huganir, R. L. (2017). Homer1a drives homeostatic scaling-down of excitatory synapses during sleep. Science, 355(6324), 511-515.

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