Dorsal premotor cortex of the macaque monkey participate grasp planning

Recently, some studies have demonstrated that the dorsomedial pathway is not only involved in arm reaching but also hand grasping. Grasp types can be decoded with multiunit activity (MUA) collected from dorsal premotor cortex (PMd) in dorsomedial pathway. However, these studies analyze and decode the neural activity during the whole grasp period. The precise function of PMd during the movement planning period has not been systematically investigated. In this study, neural signals were collected from a monkey's PMd by microelectrode array when it was performing a grip-specific task. With single neural activity (SUA) analysis, we found that 11.9% of neurons in PMd were selective to gestures during the planning period, which illustrated some neurons in PMd are related to planning. Furthermore, four grasp gesture types prediction were classified using support vector machines model (SVM) and k-nearest neighbor model (kNN) from neuron population activities. The results showed that the gesture classification accuracy reaching 60.8% by SVM and 63.9% by kNN. It infers that grasp planning is modulated by PMd neurons and that the PMd may play a central role in all phases of reach-to-grasp planning action.