7 Functional neuroimaging: linking brain anatomy to cognition

Although anatomy appears to be primarily interested in structural phenomena, its wider goal is to establish structure–function relationships and thus to explain function through a better understanding of its structural basis. Given its structural and functional complexity, this is a particularly challenging task for the brain. Since the rise of the clinical–pathological correlation method in medicine in the 19th century a major scientific endeavour has been to delineate structurally distinct areas of the cerebral cortex and associate them with specific cognitive functions. This correlation was traditionally accomplished by a combination of microstructural studies of normal brains and neuropsychological studies of lesioned brains – a procedure that was slow, tedious and methodologically difficult. Modern neuroimaging techniques with high spatial resolution (such as functional magnetic resonance imaging, fMRI) have promised an alternative approach, allowing non-invasive measurements of regionally specific changes of activity that are correlated with certain components of an experimentally controlled task. When functional neuroimaging techniques were introduced some 20 years ago, it seemed to be a matter of time until we would have obtained a complete functional map of the human brain. Has this promise come true, and if so, has it helped us to understand the functional principles of the brain?