Aging is associated with slowing of information processing, reduction in cognitive resources, moderate declines in episodic memory, and increased likelihood of failure of executive or strategic control over cognitive operations. Extensive practice in a specific cognitive domain ameliorates and delays these age-related changes within the restricted domain of practice. Performance on the tasks that depend on overlearned and well-practiced skills such as reading, use of lexicon, and engagement of semantic knowledge network are stable across most of the life span. Brain mechanisms of selective age-related changes in cognition are unclear. A small but steadily growing number of neuroimaging studies indicate that older adults evidence reduced brain activity in the task-relevant and modality-specific cortical areas while increasing the magnitude of activation and broadening the activation regions in the areas that are amodal and irrelevant to the task. An illustration of such dedifferentiation of cortical activation with age is shown in Fig. 3. In an apparent paradox, the brain regions recruited by older people are located in cortical structures that are differentially vulnerable to the effects of aging.

A contrasting interpretation of age-related differences in brain activation patterns has been offered by researchers who proposed to view it as a sign of compensation. One way to decide whether the observed pattern reflects compensation or dedifferentiation is examination of associations between activation and performance. Although the data are still sparse, several studies of healthy adults revealed that more bilateral, wide spread activation patterns is associated with better performance. Clarifying the relationships between structural and functional neuroanatomy and cognitive performance remains one of the central questions in cognitive aging research.

Breaking Bulimia

Breaking Bulimia

We have all been there: turning to the refrigerator if feeling lonely or bored or indulging in seconds or thirds if strained. But if you suffer from bulimia, the from time to time urge to overeat is more like an obsession.

Get My Free Ebook

Post a comment