Brain Fights Forgetfulness
The brains of patients with Alzheimer’s disease are able to develop new communication strategies. Until now, Alzheimer research was focused on the medial temporal brain regions, because of their strong involvement in memory. By asking patients with early Alzheimer’s disease and healthy older people to solve a three-dimensional mental rotation task, the researchers showed that the parietal regions also demonstrate crucial changes early in the disease process. Effective connectivity, a new method, allowed investigating how the functioning of one brain region can affect the functioning of another brain region. These analyses showed that brain regions in the lateral parietal areas step up their cooperation in Alzheimer patients. However, medial parietal areas, such as the posterior cingulate cortex, which is part of the central memory network, showed reduced effective connectivity in patients with Alzheimer’s disease compared to their healthy counterparts.
Blue indicates regions where patients with mild Alzheimer’s disease showed less effective connectivity than healthy older people. Red indicates regions where patients showed more effective connectivity than the healthy older people.
Interestingly, there were no differences in the behavioural performance between the patients and the healthy people. The authors concluded that the human brain uses this compensatory trick to continue functioning in an optimal manner and to stave off the devastating effects of the disease. These results provide a promising approach to understand the disease mechanisms of dementia. Furthermore, the brain’s ability to functionally reorganize stimulates the exploration of therapeutic approaches aimed at promoting neural compensation.
Jacobs, H. I. L., Van Boxtel, M. P. J., Heinecke, A., Gronenschild, E. H. B. M., Backes, W. H., Jolles, J., & Verhey, F. R. J. (2012). Functional integration of parietal lobe activity in early Alzheimer's disease. Neurology, 78, 352-360.