NEW YORK, Oct 07 (Reuters Health) -- After a head injury, the cortex -- the "thinking" part of the brain -- can shift some brain functions from damaged to undamaged regions, according to a report published in The Journal of Neuroscience.
Previous research revealed that damage to the brain results in a process termed plasticity, in which the brain reorganizes itself, with some areas of the brain increasing in size and taking on functions of nearby damaged areas.
In this study, Drs. Jayson Parker and Jonathan Dostrovsky of the University of Toronto in Ontario, Canada, attempted to shed some light on the role of the cortex and the thalamus in plasticity. The thalamus, an area deep inside the brain, receives information about senses and body movement, and relays this information to the cortex.
The scientists damaged specific areas of the brains of male rats and placed electrodes in the brains to monitor how it changed in response to the injuries.
The researchers found that simultaneous damage to the cortex and the thalamus prevented plasticity or reorganization from occurring. However, if they injured the thalamus, which set the process of plasticity in motion, and then waited one week before injuring the cortex, they did see significant changes in the structure of the thalamus, indicating that reorganization had taken place.
Parker and Dostrovsky conclude that in order for more primitive areas of the brain (such as the thalamus) to adapt, it needs instruction from the more evolved brain -- the cortex. An undamaged cortex can send signals that help the thalamus to adapt to injury, but once the changes have been made, the thalamus can maintain itself, the researchers say.
In an interview with Reuters Health, Dostrovsky said that the research may have applications "to rehabilitation following strokes and trauma and also for prevention of side effects in neurosurgery," such as "removal of tumors, and epilepsy surgery."
Dostrovsky also commented that this study only relates to reorganization of the thalamus "and it is not clear whether plasticity at other levels (of the brain) will be similarly dependent on the cortex."
