Constraints and flexibility in cortical control of the hand

Abstract

The hand performs a variety of functions, from simple grasping to delicate manipulation, largely under the control of the primary motor cortex. Perhaps as a result of biomechanical interactions between the digits at the periphery, cortical control works as a widely distributed network. Whereas for grasping the cortex may drive a limited number of fixed synergies, for more individuated finger movements cortical neurons act as diverse elements to generate a remarkable degree of flexibility. In addition to providing a substrate for motor learning and for plastic reorganization after injury, this flexible network permits rapid re-combination of elements that can promptly create entirely novel movements. Such rapid flexibility enables cortical neurons to become dissociated from bodily movement during mental imagery and during closed loop control of brain machine interfaces.