Data from: Area 2 of primary somatosensory cortex encodes kinematics of the whole arm

Proprioception, the sense of body position, movement, and associated
forces, remains poorly understood, despite its critical role in movement.
Most studies of area 2, a proprioceptive area of somatosensory cortex,
have simply compared neurons' activities to the movement of the hand
through space. By using motion tracking, we sought to elaborate this
relationship by characterizing how area 2 activity relates to whole arm
movements. We found that a whole-arm model, unlike classic models,
successfully predicted how features of neural activity changed as monkeys
reached to targets in two workspaces. However, when we then evaluated this
whole-arm model across active and passive movements, we found that many
neurons did not consistently represent the whole arm over both conditions.
These results suggest that 1) neural activity in area 2 includes
representation of the whole arm during reaching and 2) many of these
neurons represented limb state differently during active and passive
movements.