The adaptive aging brain: evidence from the preservation of communication abilities with age.

Neurofunctional reorganization with age is suspected to occur for many cognitive components including communication abilities. Several functional neuroimaging studies of elderly individuals have reported the occurrence of an interhemispheric neurofunctional reorganization characterized by more bilateral activation patterns. Other studies have indicated that the preservation of some other cognitive abilities is associated with some intrahemispheric reorganization following either a posterior-anterior or an anterior-posterior shift in aging. Interestingly, other studies have shown that age-related neurofunctional reorganization is task-load-dependent. Taken together, these studies suggest that neurofunctional reorganization in aging is based on a more dynamic, flexible and adaptive neurofunctional process than previously proposed. This review summarizes the different factors that are thought to support the preservation of the semantic processing of words in aging, and highlights a multidetermined and complex set of processes such as the nature of the specific cognitive processes, task complexity and cognitive strategy, characterizing the neurofunctional reorganization in aging that allows for optimal cognitive abilities. In so doing, it provides the background for future study looking at the neurofunctional dimensions of the impact of neurodegenerative diseases on cognitive abilities.