Motor areas beyond motor performance: deficits in serial prediction following ventrolateral premotor lesions

Previous functional MRI findings have indicated that a premotor-parietal network is involved in the perceptual processing of sequential information. Given that premotor functions have traditionally been restricted to behaviors requiring motor or sensorimotor computations, the goal of the present patient study was to further investigate whether the lateral premotor cortex is critical in purely perceptual sequencing. Patients with either ventral premotor or inferior parietal lesions, in addition to patients with prefrontal lesions and age- and gender-matched healthy controls, were tested during the processing of temporal, object-specific, and spatial sequences. Results revealed that premotor patients as well as parietal patients showed significantly higher error rates than did healthy controls on all sequence tasks. In contrast, prefrontal patients showed no behavioral deficits. These findings support the significance of the ventrolateral premotor cortex, in addition to parietal areas, in nonmotor (attentional) functions.