Sleep |
Posted on June 8, 2014 at 3:29 pm
Posted on June 8, 2014 at 3:29 pm
The benefits of a good night’s sleep are well established, however, a mechanism for exactly how sleep contributes to learning and memory has recently been detailed in a study by researchers at NYU Langone Medical Center.
In the study, published in Science,
researchers used genetically engineered mice to examine what was taking
place physically during learning. The mice were engineered such that
they expressed a glowing fluorescent protein in neurons which could be
observed and imaged. With the engineered mice in hand, scientists were
able to observe and compare the growth of dendritic spines along
branches of dendrites before and after mice learned a skill.
A dendrite is a branched extension of a nerve cell (neuron); impulses received from other cells at synapses are transmitted to the cell along the dendrite. A dendritic spine is a protrusion from a dendrite which receives inputs from excitatory axons. Previous studies have shown that learning leads to spine formation.
Ultimately, researchers found that the sleep deprived mice had less dendritic growth than the rested mice. Also, different branches grew depending on what skill was learned, an observation that Gan likened to a tree growing.
“Imagine a tree that grows leaves (spines) on one branch but not another branch. When we learn something new, it’s like we’re sprouting leaves on a specific branch,” Gan said in a release.
Interestingly, scientists found that the brain cells that were activated during training were reactivated during slow-wave deep sleep. Thus, when sleep was disrupted, dendritic spine growth was prevented.
Though sleeping is often viewed as an opportunity to rest the mind, the authors explain how our mind is actually quite busy. This is evidenced by the sort of replay, or “neuronal reactivation”, observed in neurons during periods of sleep.
“Finding out sleep promotes new connections between neurons is new, nobody knew this before, “professor Gan told the BBC. “We thought sleep helped, but it could have been other causes, and we show it really helps to make connections and that in sleep the brain is not quiet, it is replaying what happened during the day and it seems quite important for making the connections.”
Article retrieved from: http://ht.ly/xWqX0
Image retrieved from: http://www.studycram.com/images/sleep-student.jpg
A dendrite is a branched extension of a nerve cell (neuron); impulses received from other cells at synapses are transmitted to the cell along the dendrite. A dendritic spine is a protrusion from a dendrite which receives inputs from excitatory axons. Previous studies have shown that learning leads to spine formation.
“We’ve known for a long time that sleep plays an important role in learning and memory. If you don’t sleep well you won’t learn well,” says senior investigator Wen-Biao Gan, PhD, NYU Langone Medical Center. “But what’s the underlying physical mechanism responsible for this phenomenon?The mice were taught to balance on a spin rod, which over time spun faster and faster. Researchers first observed the expected growth of new spines along dendritic branches and then set up experiments to determine the effect that sleep had on this growth. Two sets of mice were trained on the rod for an hour and when one group was allowed to rest for 7 hours following training, the other group was kept awake.
Ultimately, researchers found that the sleep deprived mice had less dendritic growth than the rested mice. Also, different branches grew depending on what skill was learned, an observation that Gan likened to a tree growing.
“Imagine a tree that grows leaves (spines) on one branch but not another branch. When we learn something new, it’s like we’re sprouting leaves on a specific branch,” Gan said in a release.
Interestingly, scientists found that the brain cells that were activated during training were reactivated during slow-wave deep sleep. Thus, when sleep was disrupted, dendritic spine growth was prevented.
Though sleeping is often viewed as an opportunity to rest the mind, the authors explain how our mind is actually quite busy. This is evidenced by the sort of replay, or “neuronal reactivation”, observed in neurons during periods of sleep.
“Finding out sleep promotes new connections between neurons is new, nobody knew this before, “professor Gan told the BBC. “We thought sleep helped, but it could have been other causes, and we show it really helps to make connections and that in sleep the brain is not quiet, it is replaying what happened during the day and it seems quite important for making the connections.”
Article retrieved from: http://ht.ly/xWqX0
Image retrieved from: http://www.studycram.com/images/sleep-student.jpg
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