The proposed research aims to obtain scientific knowledge on the visuomotor transformations in posterior parietal cortex (PPC) and motor cortex (MC) by characterizing the functional similarities and differences between both regions in tetraplegic participants enrolled in a clinical trial designed to advance the development of neural prosthetics. In experiments from the last grant period, we demonstrated that the functional characteristics of these brain regions remain intact over time, even following spinal cord injury and prolonged use of brain-machine interfaces (BMIs). We identified overlapping neural populations in both areas that encode motor variables for effectors throughout the body using mixed selectivity, a coding scheme that combines multiple variables within the same neurons. Despite these similarities, we found that the encoding properties of MC and PPC exhibit essential differences. While MC preferentially encodes the contralateral hand, PPC shows similar encoding strength for all effectors across the body. Furthermore, PPC is actively involved in planning and executing motor actions, whereas MC shows mainly activation during the execution of movements. PPC also shows a compositional code for observed and felt somatosensory stimuli. This renewal proposal seeks to broaden our understanding of the neural encoding mechanisms within PPC and MC by exploring how context affects the previously unexamined sensorimotor processes of navigation, drawing, and simultaneous, coordinated movements . In Aim 1, we will study the neural representations of allocentric and egocentric cognitive maps during two virtual reality navigation tasks performed under BMI control. We hypothesize that PPC encodes both allocentric and egocentric cognitive maps, while MC only encodes egocentric motor execution during these navigational tasks. Aim 2 will examine whether the brain uses compositional encoding of visuomotor variables for drawing. Our hypothesis is that PPC uses compositional