279 Apraxia and the temporal lobe in action: a role for biological motion

Limb apraxia is a syndrome that affects the ability to perform skilful actions, despite intact elementary motor and sensory systems. Using voxel-based lesion symptom mapping in a large cohort of 387 stroke patients we determined the neuroanatomy of three tasks traditionally used to study praxis skills in patient populations: these included a meaningless gesture imitation task, a gesture production task involving pantomime of transitive and intransitive gestures and a gesture recognition task, involving recognition of these same categories of gestures. Lesions associated with reduced performance in these tasks involved an integrated network previously described in biological motion, with input areas comprising left pre-striate and occipital regions, left superior temporal sulcus and motor output areas comprising left premotor area, left striatum and the white matter underlying the left primary motor cortex. This study confirms a role for the left hemisphere in limb apraxia and supports the hypothesis it is a white matter disconnection syndrome, whilst shedding new light into the nature of the behavioural deficits described in the disorder comprising parts of an integrated network of brain areas described in biological motion.