Motor Error in Parietal Area 5 and Target Error in Area 7 Drive Distinctive Adaptation in Reaching

Errors in reaching could result from imperfect motor commands (motor error) or from target movements (target error). To clarify whether and where these two types of errors are represented in the parietal cortex, we examined neuronal activities of areas 5 and 7 while two monkeys performed rapid target-reaching. Here, we show that area 5 neurons encoded motor errors in particular, whereas area 7 neurons encoded both. Post-movement microstimulation to area 5 caused adaptation to cancel the motor error, whereas stimulation to area 7 caused adaptation to compensate for the target error. We suggest that area 5 provides signals for adapting to motor errors, whereas area 7 provides signals for adapting to target errors.