A new study from The Scripps Research Institute (TSRI) in Florida suggests through animal models that sleep suppresses the activity of specific cells that promote forgetting. Published in the journal Cell, the researchers believe their model reveals the complexities of sleep and how at least some memories will last.

Ron Davis, the senior author of the latest study, suggests that many scientists focus on a narrow aspect of the associations between sleep and memory. “Many scientists have tried to figure out how we learn and how our memories become stabilized, but far less attention has been paid to forgetting, which is a fundamental function of the brain and potentially has profound consequences for the development of memory therapeutics. Our current study merges the neuroscience of forgetting, that is, the brain mechanisms that lead to forgetting, and the psychology of forgetting into an integrated picture.”

In the animal study, Davis and colleagues investigated the neurotransmitter dopamine and sleep. Dopamine is one of the neurotransmitters that helps the brain adapt and change in response to learning and memory formation. The team discovered that increasing sleep either by drugs or by genetically stimulating the neural sleep circuit decreases the signaling activity of dopamine, thus improving memory. They also found that increasing the mice’s arousal increases the speed of forgetting by stimulating dopamine’s signaling.

"As sleep progresses to deeper levels," Davis adds, "dopamine neurons become less reactive to stimuli, and this leads to more stable memories."

Sleep is a very attractive and debated topic. One of the significant challenges with sleep is that there is minimal communication between the sleeper and the external environment. Scientists are finding more research that sleep is crucial for the preservation and well-being of our brains. Though the National Sleep Foundation hints that sleep is essential for a person’s health, many people are not getting enough or are getting disrupted amounts.

The Institute of Medicine reports that 50 to 70 million Americans suffer from some form of long-term sleep or wake disorder adversely affecting one’s health and longevity. Long-term effects can include hypertension, diabetes, obesity, heart attack, and stroke. Neurologically, long-term disrupted sleep has been associated with high irritability, depression, and Alzheimer’s disease.

The Centers for Disease Control and Prevention recommends adults getting at least seven to eight hours of sleep every night. 

Primary Reference:

Berry, J. A., Cervantes-Sandoval, I., Chakraborty, M., & Davis, R. L. (2015). Sleep Facilitates Memory by Blocking Dopamine Neuron-Mediated Forgetting.Cell.

Additional References:

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