Fig. 4.

Montage depicting the precentral motor lesion site in monkeys in the classic studies of Denny-Brown and Botterell ([23]; Fig. 6), Glees and Cole ([38]; Fig. 8, Am Physiolog Soc, J Neurophysiol, used with permission), Travis ([107]; Fig. 6, Oxford University Press, Brain, used with permission) and Passingham et al. ([84]; Fig. 1, Oxford University Press, Brain, used with permission). In the Denny-Brown map, the crosshatching indicates the surgical ablation which involved the arm and leg representations of the precentral motor cortex. In contrast to the typical large precentral lesion induced in most studies, the M1 lesion created in the Glees and Cole work (blackened area abutting the central sulcus), as well as the Travis [107] work (pericentral region indicated by the arrows), was small and discretely limited to the distal forelimb region of the arm representation. The lesion site in the Passingham figure is depicted by the diagonal lines and involved the face, arm, shoulder and leg representations of the precentral motor cortex.