Effector general representation of movement goals in human frontal and parietal cortex

In the nonhuman primate, discrete parts of premotor frontal and parietal cortex appear to code for movements of different effectors. However, the evidence regarding homologous effector selectivity within the human brain remains inconclusive. Here, we measured neural activity in the human brain using functional magnetic resonance imaging while participants remembered a target location and planned either saccades or reaches that matched the rich kinematics used in seminal monkey studies. We compared activity patterns during the planning period and used assumption-free multivariate searchlight analysis to identify brain regions that could decode the spatial goals of planned movements. Critically, we performed two types of decoding analyses to determine if the spatial information embedded in activation patterns was effector-specific or effector-general. For effector-specific spatial coding, we compared brain regions that could decode target locations within each effector. However, we did not identify areas that coded spatial information in one effector but not the other. For effector-general spatial coding, we performed spatial decoding using trials across effectors and conducted cross-effector decoding. Both analyses identified several areas in the frontal and parietal regions that encoded spatial information for both effectors, including precentral sulcus, superior parietal lobe, and intraparietal sulcus. Our results indicate that premotor frontal and parietal cortex encode the spatial metrics of movement goals that can be read out and converted into effector-specific motor metrics for saccades and reaches.