Did a change in sensory control of skilled movements stimulate the evolution of the primate frontal cortex?
The classical view of the evolution of such skilled movements as use of the hand and digits for reaching and grasping posited that these movements had their origin in the primate lineage. The hypothesis was that the permissive influence of adaptations to an arboreal environment led to the evolution and elaboration of these skills. Associated with skilled movements were increases in the size of the frontal lobe, temporal lobe, and cerebellum and the elaboration of new connections between these structures and other cortical regions, the brainstem, and spinal cord. The classical view saw rodents as phylogenetically old and relatively unrelated animals, displaying no skilled movements, and whose normal repertoire of behavior had little dependence on the frontal lobes. Here, evidence is reviewed that shows that the classical view of the origins of skilled movements is incorrect. Skilled movements are phylogenetically old, evolved in relation to food handling, and are especially well develop
