Posts Tagged Brain Recovery
- When recovering from a brain injury, getting back in the swing of things may be more effective than a prolonged period of rest, according to a new study in mice. These findings offer a compelling example of the brain’s remarkable capacity to adapt in response to trauma. They also point to new, activity-centered treatment strategies that could one day result in faster and more complete recovery times for patients looking to regain mobility after a brain damage or a stroke.
When recovering from a brain injury, getting back in the swing of things may be more effective than a prolonged period of rest, according to a new Columbia study in mice. These findings offer a compelling example of the brain’s remarkable capacity to adapt in response to trauma. They also point to new, activity-centered treatment strategies that could one day result in faster and more complete recovery times for patients looking to regain mobility after a brain damage or a stroke.
This research was reported today in the journal Nature.
“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 Randy Bruno, PhD, the study’s senior author and a principal investigator at Columbia’s Mortimer B. Zuckerman Mind Brain Behavior Institute. “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.”
Today’s study marks an important step in the research team’s multi-year effort to unravel the workings of the brain’s cerebral cortex. The cerebral cortex is the largest region of the mammalian brain and plays a key role in many functions, from sight and smell to movement and memory. For this study in mice, researchers focused on a part of the animals’ cerebral cortex called the barrel cortex, which is thought to be critical 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 Y. Kate Hong, PhD, a postdoctoral associate in the Bruno lab and the paper’s first author.
The researchers placed mice in a dark box and trained them to search for a nearby object with their whiskers. When the mice detected the object, they pulled a lever with their paw to dispense water as a reward. Conventional wisdom argued that this kind of detection task depends almost entirely on a functioning sensory cortex — in this case, the barrel cortex.
To confirm this was true, the researchers used laser light to temporarily turn off barrel-cortex cells, a popular technique known as optogenetics. As expected, animals had difficulty whisking while the cells were turned off. And when the team then permanently removed their barrel cortex, the animals could not perform the task the next day.
But on day two, the animals’ performance suddenly recovered to original levels. “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.”
The researchers suspect that other, more primitive brain regions may be involved to a greater degree than previously known — a hypothesis the team is currently investigating.
“Rather than being confined to one particular brain region, sensory information is distributed across many areas,” said Dr. Hong. “This redundancy allows the brain to solve problems in more than one way — and can serve to protect the brain in case of injury.”
But to recover, did the animals simply need a day of rest, or did they need to be re-exposed to the task? To find out, the team performed another round of experiments, with one key difference: They let the mice rest for three days before re-exposing them to the task.
This time, the mice showed incomplete rehabilitation. While they did eventually regain some sensation, they recovered more slowly than the first set of mice. The key to a speedy recovery appeared to lie in re-engaging with the task early — not the passage of time.
As to why all mice perform so poorly during the first 24 hours, regardless of what they do? The reason may lie in the disturbance that the brain has just 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.”
The manipulations undertaken by the Columbia team are not unlike what happens in the brain of a person having a stroke. Dr. Bruno and his team caution that their research on rodents cannot be directly applied to human beings. But they hope their findings will be further explored by neurologists looking to improve recovery times for their patients.
“We tend to immobilize people when they’ve suffered a stroke; the recovery of seemingly simple tasks — walking, grasping — can be a long road,” said Dr. Bruno. “Our findings suggest that maybe, in some cases, patients could be reintroduced to these activities much earlier in order to speed recovery.”
Materials provided by The Zuckerman Institute at Columbia University. Note: Content may be edited for style and length.
- Y. Kate Hong, Clay O. Lacefield, Chris C. Rodgers, Randy M. Bruno. Sensation, movement and learning in the absence of barrel cortex. Nature, 2018; DOI: 10.1038/s41586-018-0527-y
The Zuckerman Institute at Columbia University. “Brain recovery: Activity, not rest, may speed recovery after brain injury.” ScienceDaily. ScienceDaily, 17 September 2018. <www.sciencedaily.com/releases/2018/09/180917111622.htm>.
Physicians in neurorehabilitation often deal with pharmacological problems, marshalling antihypertensive, anticonvulsive and anticoagulation treatments. In addition, there is growing interest in positive or negative effects of medication on brain recovery. Of great importance is the concept of so-called “detrimental drugs” known to negatively influence processes of brain reorganization and recovery. To this group belong anti-convulsive agents such as phenytoin and barbiturates as well as benzodiazepines, butyrophynones and the antihypertensives clonidine and prazosine. Whenever possible these drugs should be avoided in the course of brain recovery after a cerebral lesion.
For only two substances (the SSRI fluoxetine and cerebrolysin, a mixture of pleotropic neuropeptides and amino acids) large randomized controlled trials showed a positive influence on facilitating motor recovery after the stroke. Both substances probably work through pleotropic multiple molecular mechanisms and not as a one-to-one agonist on the receptor. In general the use of antidepressive agents especially SSRI after the stroke can also be recommended for non-depressed stroke patients.
Also dopaminergic drugs have been shown in smaller studies to positively influence functional recovery. Considering their low side-effect profile, the tentative use of 100 mg of L-Dopa per day in the subacute phase of the stroke can be recommended. In MS patients the use of antidepressive agents is also recommend to improve life quality.
In patients with diminished states of consciousness amantadine is the only substance which a randomized controlled study proved to have at least some transient effect. The use of amantadine can be recommended for the improvement of the level of consciousness in these patients.
Physicians engaged in neurological rehabilitation constantly have to deal with aspects of primary pharmacological treatment of patients, including control of high blood pressure, anticonvulsive therapies and suitable anticoagulation treatment to reduce risk factors and secondary problems. Furthermore, neurological rehabilitation must also take into account pharmacological issues relating to restoration of brain function. This concerns the avoidance of pharmaceuticals that may interfere with brain recovery as well as the use of drugs that may have a positive affect on brain function. This overview aims to provide a critical summary of the options available to the clinician in the pharmacological treatment of patients after acute neurological events as part of the process of the rehabilitation of brain organization and restoration of brain function, as well as discuss the avoidance of potentially negative effects of pharmacological interventions. […]
[Abstract] Factors affecting post-stroke motor recovery: Implications on neurotherapy after brain injury
- Motor recovery after stroke is a multifactorial and dynamic process.
- Advanced age, African American race, and female gender are major socioeconomic factors affecting stroke recovery.
- Extent of initial injury after stroke is a major independent predictor of recovery.
- Neurorehabilitation strategies provide a unique opportunity for enhancing recovery.
- Genetic polymorphisms especially in BDNF may influence post-stroke recovery process.
Neurological disorders are a major cause of chronic disability globally among which stroke is a leading cause of chronic disability. The advances in the medical management of stroke patients over the past decade have significantly reduced mortality, but at the same time increased numbers of disabled survivors. Unfortunately, this reduction in mortality was not paralleled by satisfactory therapeutics and rehabilitation strategies that can improve functional recovery of patients.
Motor recovery after brain injury is a complex, dynamic, and multifactorial process in which an interplay among genetic, pathophysiologic, sociodemographic and therapeutic factors determines the overall recovery trajectory. Although stroke recovery is the most well-studied form of post-injury neuronal recovery, a thorough understanding of the pathophysiology and determinants affecting stroke recovery is still lacking.
Understanding the different variables affecting brain recovery after stroke will not only provide an opportunity to develop therapeutic interventions but also allow for developing personalized platforms for patient stratification and prognosis. We aim to provide a narrative review of major determinants for post-stroke recovery and their implications in other forms of brain injury.
Stroke Rehabilitation Clinician Handbook
Robert Teasell MD, Norhayati Hussein MBBS MRehabMed