Synapses in the hippocampus are larger and stronger after sleep deprivation, according to new research in mice published in JNeurosci. Overall, this study supports the idea that sleep may universally weaken synapses that are strengthened from learning, allowing for new learning to occur after waking.
Sleep is thought to recalibrate synaptic strength after a day of learning, allowing for new learning to take place the next day. Chiara Cirelli and colleagues at the University of Wisconsin-Madison examined how synapses in the hippocampus, a structure involved in learning, changed following sleep and sleep deprivation in mice.
Consistent with previous studies in the cortex, the researchers observed that synapses were larger, and therefore stronger, after the mice were awake for six to seven hours compared to after they were asleep for the same amount of time. Additionally, the researchers found that the synapses were strongest when the mice were forced to stay awake and interact with new stimuli, compared to mice that stayed awake on their own. This is consistent with the hippocampus' role in learning, and suggests that synaptic changes take place when learning occurs, not merely from being awake.
Manuscript title: Sleep Deprivation by Exposure to Novel Objects Increases Synapse Density and Axon-Spine Interface in the Hippocampal CA1 Region of Adolescent Mice
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JNeurosci, the Society for Neuroscience's first journal, was launched in 1981 as a means to communicate the findings of the highest quality neuroscience research to the growing field. Today, the journal remains committed to publishing cutting-edge neuroscience that will have an immediate and lasting scientific impact, while responding to authors' changing publishing needs, representing breadth of the field and diversity in authorship.
About The Society for Neuroscience
The Society for Neuroscience is the world's largest organization of scientists and physicians devoted to understanding the brain and nervous system. The nonprofit organization, founded in 1969, now has nearly 37,000 members in more than 90 countries and over 130 chapters worldwide.