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Reach, Grasp, and Manipulation

Diagram of Four Object Task

Subjects perform a repertoire of manipulations on
various objects in different locations.

The hand often is used for manipulating an object, but much more is known about how the nervous system controls the reach and grasp that typically precedes manipulation. We are exploring the neural and muscular activity underlying manipulation, and how that relates to the activity that controls the preceding reach and grasp.


The long-term goal of the present project is to understand the cortical control of voluntary movements used to reach out, grasp and manipulate. These movements typically are considered as distinct processes, controlled from proximal versus distal sub-regions of the upper extremity representation in the primary motor cortex, and influenced via distinct inputs from dorsal versus ventral areas of the premotor cortex, respectively. Here we propose to investigate the neurophysiological activity underlying the seamless integration of reaching, grasping, and manipulation into a single coordinated motor act. Specifically, the present proposal aims to:

  1. determine whether single neurons and other neurophysiological activity in the primary motor cortex, dorsal premotor cortex and ventral premotor cortex are modulated in relation to reaching, to grasping, or to both;
  2. determine how and where manipulative actions of the arm and hand are represented in the primary motor and premotor cortex;
  3. determine how the grip forces and the load forces used in manipulation are represented and controlled. Improved understanding of these processes will lead to improved rehabilitation for functional recovery and to improved neuro-prosthetic devices for patients affected by numerous neurological diseases including stroke, amyotrophic lateral sclerosis, multiple sclerosis, traumatic brain or spinal cord injury, and cerebral palsy.

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