ABSTRACT
A number of key molecular and structural changes occur in the brain as it ages. The relationship between such changes and function of the aged brain are poorly understood. Ageing brings with it preferential decline in fluid cognitive abilities, with preservation of crystallised intellectual abilities1 (Chapter 6). In particular, age-related decline is seen in speed of information processing, working memory and complex attention. The underlying mechanisms of the decline in some cognitive domains remain obscure. Although structural correlates of this phenomenon such as preferential decline in frontal lobe volumes have been noted2 (Chapter 4), a less than robust relationship between cognitive function and frontal lobe atrophy has been observed.3,4 Such discrepancy emphasises the importance of exploring the functional correlates of age-related neuropsychological decline. Modern imaging techniques are appropriate tools to probe the interrelationship between molecular, structural and functional changes that occur during the ageing process. One of the salient issues to be addressed is that of resting cerebral metabolic and blood flow correlates of senescent cognitive change. To this end, this chapter reviews relevant neuroimaging
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