Fascinating insight into mechanisms that underlie recovery after damage to a region of the brain important for memory and attention is provided by new research.
The research, published by Cell Press in the November 4th issue of the journal Neuron
, highlights the role of undamaged portions of the brain that can "take over" and support the recovery of function.
Brain damage can have devastating consequences, depending on the location and severity of the injury. Damage to an area of the brain called the prefrontal cortex often results in deficits in memory and attention. However, people can 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," explains lead study author, Dr. Bradley Voytek from the University of California at Berkeley.
Dr. Voytek and colleagues designed a study examining brain activity in patients with damage to the prefrontal cortex on only one side of the brain. Patients and matched control subjects performed a visual working memory task or a visual attention task. Importantly, the researchers presented stimuli to one hemisphere at a time, allowing them to challenge either the intact or damaged prefrontal cortex in the patients with brain damage. 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."