Pantomime of object use: a challenge to cerebral localization of cognitive function

The paper illustrates difficulties and insecurities of localizing cognitive functions with the example of pantomime of object use. Numerous studies have established a particular sensitivity of this task to left brain damage (LBD), but there is no agreement as to how components of its cognitive architecture are related to the laterality and intrahemispheric location of responsible lesions. Apraxia and asymbolia have been suspected to be crucial for explaining the vulnerability of pantomime to LBD, but analysis of correlations between impairments of pantomime, imitation of gestures, drawing from memory, and language in patients with LBD and aphasia suggests that neither of these putative deficits can adequately account for the data. It rather appears that pantomime taps a central aspect of left hemisphere function which affects performance on a great number of otherwise widely different tasks and which is not bound to any particular location within the hemisphere. I discuss ways to resolve apparent conflicts between this interpretation and the findings of double dissociations between pantomime and imitation in clinical case studies and of circumscribed left parietal activation during pantomime in functional neuroimaging.