Prehension kinematics in humans and macaques

Non-human primates, especially rhesus macaques, have been a dominant model to study sensorimotor control of the upper limbs. Indeed, human and macaques have similar hands and homologous neural circuits to mediate manual behavior. However, few studies have systematically and quantitatively compared the manual behaviors of the two species. Such comparison is critical for assessing the validity of using the macaque sensorimotor system as a model of its human counterpart. In this study, we systematically compared the prehensile behaviors of humans and rhesus macaques using an identical experimental setup. We found human and macaque prehension kinematics to be generally similar but with a few subtle differences. Humans and macaques have similar major axes of movements and similar kinematics subspaces. Human grasps are more object-specific and the movement of human digits are less correlated with each other. Monkeys demonstrate more stereotypical grasping behaviors that are common across all grasp conditions. Our results bolster the use of the macaque model to understand the neural mechanisms of manual dexterity.