We have proposed that the visuokinesthetic engrams responsible for programming skilled motor movements are stored in the left parietal lobe. Both gestural discrimination and comprehension studies showed that two forms of ideomotor apraxia could be identified. Unlike patients with anterior lesions, those with parietal lesions could not discriminate or comprehend gestures. Apractic patients with parietal lesions could process gestural information in primary memory in much the same manner as normal subjects and nonapractic aphasics. Secondary memory or long-term retention (consolidation), however, was impaired in these patients. These observations provide support for the hypothesis that visuokinesthetic motor engrams are stored in the left parietal lobe and that destruction of these engrams may induce discrimination, comprehension, and memory disorders for gestures. © 1985, Elsevier Science & Technology.
