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How Sleep Reinforces Neuronal Growth After Learning

If you have ever collapsed on your bed after a hard day of work, you are probably more than familiar with how important sleep is to refresh the mind and body. Scientists have already documented how important a good night’s sleep can be, but there are still many unanswered questions that sleeping specialists are trying to understand. Until recently, even the most well learned scientists were not sure about how the exact mechanism for sleeping helped contribute to memory and learning processes in the human mind.

In the recent study that was conducted and published in Science magazine, scientists set out to see how sleeping was connected to neuronal growth in the mind, and what effect different sleep disorders can have on mental health. During the study itself, the researches used specially genetically engineered mice in order to see what physical activities were occurring in the brain as the mice were learning. In order to be able to inspect the visible results, the mice that were used in the experiment were engineered so that a glowing protein in their braids could be traced and imaged as they learned. With the aid of these mice, scientists were able to see how and what parts of the brain were affected during the learning process. They carefully monitored and recorded the growth of this protein as it developed new sections of information in the brain before and after the mice learned different skills throughout their training.

As was to be expected, there was increased dendrite growth in the mice as they learned new skills, and though the exact progression varied from mouse to mouse, researchers could see the average means for growth thanks to the proteins. A dendrite is a branching extension that grows from a nerve cell, which is known as a neuron. Neurons receive impulses from other cells at special points called synapses, which are then transmitted to the cell through the dendrite. The dendritic spine is a special protrusion from the dendrite that receives those inputs. Scientists have always linked the growth and formation of these spines with learning and how we receive and store information. which receives inputs from excitatory axons.

Scientists have always known that sleep can play a very important role in the development of memory and the learning process itself. It is as simple as the fact that if you do not sleep well, then you may not learn well either. These are phenomena that have not only been documented in clinical trials, but also felt by millions of people every day all over the country. There are innumerable public service announcements for children that stress the importance of resting as it related to learning and mental development. Now, with the stage set by the proteins in the rats’ brains, scientists will be able to have a better chance of understanding exactly what kind of learning processes are affected by sleeping.

For the purposes of the experiment, the mice were taught to maintain their balance as they stood over a spinning rod, which, as time went on, would begin to spin more quickly. Through this experiment, the researchers were able to observe the standard growth of the dendritic spines over the branches. The next step of the experiment involved seeing what effect sleeping would have on the growth of these spines. In order to view results accurately, the mice were split up into two groups and were trained with the spinning rod for approximately an hour. For the rest portion, one group of mice was given a resting time of seven hours, immediately following the training. The other group, however, was kept awake in order to see how the neuronal growth of that group would be affected by a lack of rest.

At the conclusion of the experiment, the researchers found that the sleep deprive group of mice has experience significantly less growth mental growth than the group that was allowed to rest. Additional research found that different branches grew in their minds, depending entirely on what type of skill was learned. The scientists observing the experiment likened the growth of these spines to the growth of a tree. In order to visualize the growth of these sections of the brain after learning, it is important to imagine the tree as it grows leaves, which, in this case, are the spines. These leaves can grow on a single branch, but may not grow on another branch, depending on how the tree itself is taken care of. As we learn new information, we sprout new leaves on specific branches, which correspond to differently categorized skills and data as they are stored in our minds.

Another point of interest that scientists discovered was that not only does rest affect the growth of the spines, but whether or not they grow at all. The parts of the brain that were activated as the rats trained were reactivated again after the periods of rest. This same effect was not observed in the other group, which means that when your sleeping time is disrupted, the growth of dendritic spines may be prevented entirely.

While many see sleeping as the chance to rest our minds, the scientists stressed that it was important to not forget that the mind remains busy, even during resting periods. This was observed in the rats that were given the opportunity to enjoy a sleeping period. Neuronal growth is reactivated after periods of rest, and sleep disorders can have a negative effect on the brain’s capacity to learn. The conclusion of this study showed that not only is sleep crucial to the mental development process, but it may have a much larger role in our capacity to store knowledge than we had originally thought.