November 5, 2010

Recovery After Brain Damage

(Ivanhoe Newswire) -- Novel research from the shores of California has provided insight into mechanisms that trigger recovery after damage to the brain imperative for memory and attention.  This research highlights the role of undamaged sections of the brain that can "take over" and support the recovery function.

"Brain damage" or "brain injury" (BI) is the destruction or degeneration of brain cells, often with an implication that the loss is significant in terms of functioning or conscious experience.

Furthermore, it can have detrimental consequences, depending on the location and severity of the injury.  When damage to an area of the brain called the prefrontal cortex (PFC) "“ necessary in planning complex cognitive behaviors, personality expression, decision-making and moderating correct social behavior "“ often results in deficits in memory as well as attention.

However, people are known to recover some function over time. Studies examining recovery after motor or language deficits have indicated that undamaged regions of the brain can compensate for the damaged areas.  While it is clear that neural plasticity is necessary for functional recovery after damage to the prefrontal cortex, specific mechanisms of cognitive recovery are not as well understood.

"In our current study, we were interested in examining whether intact cognitive performance in patients with damage to the prefrontal cortex in one hemisphere of the brain is mediated by functional compensation of the prefrontal cortex on the intact, undamaged side of the brain," which lead study author, Dr. Bradley Voytek from the University of California at Berkeley was quoted as saying.

Dr. Voytek and colleagues designed a study investigating brain activity in patients with prefrontal cortex injuries on merely one side of the brain.  Both patients and matched control subjects alike performed visual working memory tasks as well as visual attention tasks.  The researchers most prominently presented stimuli to one hemisphere at a time, allowing them to challenge either the intact or damaged prefrontal cortex in patients with brain damage.  Furthermore, they observed transient increases in activity related to attention and memory in the intact prefrontal cortex within a second of stimulus presentation to the damaged hemisphere.

"Our results show that the neural changes observed in movement recovery after motor cortex damage expand to cognitive domains and apply to a dynamic model of memory and attention compensation by the intact, undamaged cortex," concludes Dr. Voytek.  "We demonstrate that brain recovery can manifest itself as transient changes in information processing occurring on a sub-second timescale after the injured brain has been challenged to perform, supporting a dynamic and flexible model of neural plasticity."

SOURCE: Neuron, 4 November 2010