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Activity may be the best way for the brain to recover from trauma

A new study from Columbia University has found that resting may not be the best way to bounce back after a brain injury. An investigation focused on mice revealed that physical activity could promote faster and greater recovery after brain trauma.

The results of the research provide compelling evidence of the brain’s powerful capacity to adapt in response to trauma. The research also reveals potential treatment strategies that could ultimately result in better mobility following a stroke or brain damage.

Dr. Randy Bruno is a principal investigator at Columbia’s Mortimer B. Zuckerman Mind Brain Behavior Institute and the study’s senior author.

“Lengthy rest periods are supposed to be key to the brain’s healthy recovery, but our study in mice demonstrates that re-engaging the brain immediately after injury can actually be more helpful than resting it – an observation that was completely unexpected,” said Dr. Bruno.

“While these findings underscore the brain’s complexity, the nature of which we are only beginning to tease apart, they also provide a new avenue of research into more effective rehabilitation efforts for serious brain injuries.”

In mammals, the cerebral cortex is the largest region of the brain and plays a critical role in many key functions, such as sight, smell, movement, and memory.

The researchers developed a study with mice that focused on a part of the cerebral cortex called the barrel cortex. This region is thought to be important for sensing and analyzing signals during whisking – when a mouse moves its whiskers to strike objects.

“Mice use whiskers to sense their surroundings the way we use our fingers,” said study first author Dr. Y. Kate Hong.

The team placed mice in a dark box and trained them to search for a nearby object with their whiskers. The experts speculated that this type of detection depended almost entirely on the barrel cortex.

To investigate, the researchers used laser light to temporarily turn off barrel-cortex cells and found that this made it difficult for the animals to perform whisking. When the team permanently removed the barrel cortex, the mice could not perform the task at all during the following day. On day two, however, their whisking  ability made a full recovery.

“This came as a huge surprise, since it suggested that tactile sensation, such as whisker-based touch, may not completely rely on the cortex,” said Dr. Hong. “These findings challenge the commonly held, cortex-centric view of how the brain drives touch perception.”

Next, the team wanted to determine if the animals simply needed a day of rest or if  the repeated exposure to the task is what helped them to recuperate so quickly. In order to find out, the same experiment was conducted. This time, however, the mice rested for three days before being re-exposed to the task.

While the mice did eventually regain some sensation, they recovered much more slowly and not as completely compared to the mice in the first experiment.  

The research suggests that the key to a speedy recovery was re-engaging with the task early without letting a lot of time pass. The poor performance during the first 24 hours may be explained by the disruption that the brain has experienced.

“The cortex connects to almost every other structure in the brain, so manipulating it may temporarily disrupt connected structures – in essence shocking those areas that would normally enable a behavior,” said Dr. Bruno. “Perhaps this sudden and brief loss in sensation is due to that initial disruption to the animals’ abilities – rather than being due to the loss of any information stored in the barrel cortex itself.”

“We tend to immobilize people when they’ve suffered a stroke; the recovery of seemingly simple tasks – walking, grasping – can be a long road. Our findings suggest that maybe, in some cases, patients could be reintroduced to these activities much earlier in order to speed recovery.”

The study is published in the journal Nature.

By Chrissy Sexton, Staff Writer

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