I imagine it is highly cited because it proposes what is probably the first integrative theoretical account in the domain of functional neuroimaging of aging. The paper proposes that, under similar circumstances, prefrontal activity during cognitive performances tends to be less lateralized in older than in younger adults. The article reviews supporting evidence and proposes a theoretical framework for interpreting this evidence, including the distinction between compensation and dedifferentiation accounts.

The paper proposes a theoretical account of recent functional neuroimaging evidence from many different laboratories. It also considers the ideal methods for testing this account.

As we age, the structure and function of our brain declines. On the bright side, the results of recent brain imaging studies suggest that the aging brain may counteract neural decline through a process of functional reorganization. In particular, these studies show that older adults recruit both hemispheres to perform tasks that require basically one hemisphere in young adults. Available evidence suggests that this change plays a compensatory role in the aging brain.

In 1997, we found that during a recall task, prefrontal activity was right-lateralized in young adults but bilateral in older adults (Cabeza et al., 1997, J Neurosci; Cabeza et al., 1997, Neuroreport). We suggested that this change could reflect a compensatory mechanism in the aging brain. Since 1997, the finding of a more bilateral pattern of prefrontal activity in older adults has been replicated many times. Thus, I recently proposed that this change reflects a general aging phenomenon (Cabeza, 2002, Psych Aging). Strong evidence for the compensation account of this phenomenon was provided by a study that found bihemispheric recruitment in high- but not in low-performing older adults (Cabeza et al., 2002, Neuroimage).

Roberto Cabeza
Assistant Professor
Department of Psychological and Brain Sciences
Center for Cognitive Neuroscience
Duke University
Durham, NC, USA