Unconstrained three-dimensional reaching in Rhesus monkeys

• Published in: Experimental brain research Vol. 209; no. 1; pp. 35 - 50
• Main Authors: Jindrich, Devin L, Courtine, Gregoire, Liu, James J, McKay, Heather L, Moseanko, Rod, Bernot, Timothy J, Roy, Roland R, Zhong, Hui, Tuszynski, Mark H, Reggie Edgerton, V
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.03.2011; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Animals; Arm - innervation; Arm - physiology; Biological and medical sciences; Biomechanical Phenomena - physiology; Biomedical and Life Sciences; Biomedicine; dynamics; Elbow; Elbow Joint - physiology; Electromyography; Electromyography - methods; EMG; Eye and associated structures. Visual pathways and centers. Vision; Fundamental and applied biological sciences. Psychology; Gravitation; Hand - physiology; Hand Strength - physiology; Joints - physiology; Kinematics; Macaca mulatta; Macaca mulatta - physiology; Macaca mulatta - psychology; Monkeys & apes; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Motor cortex; Multi-joint; Muscle; Muscle Contraction - physiology; Muscle function; Muscle, Skeletal - physiology; Neurology; Neuropsychological Tests - standards; Neurosciences; Orientation - physiology; Physiological aspects; Prehension; Psychological aspects; Psychomotor Performance - physiology; Range of Motion, Articular - physiology; Reach-to-grasp; Research Article; Rhesus monkey; Shoulder Joint - physiology; Space Perception - physiology; Spinal cord injuries; Upper limb; Vertebrates: nervous system and sense organs; Vision, Ocular - physiology; United States; United States > US; California; Multi-joint; Dynamics; Kinematics; Upper limb; Reach-to-grasp; Muscle; Electromyography; Prehension; EMG; Central nervous system; Monkey; Electrophysiology; Osteoarticular system; Segmental; Shoulder; Primates; Stiffness; Gravity; Gripping; Joint; Hand; Vertebrata; Mammalia; Body movement; Strategy; Curvature
• ISSN: 0014-4819; 1432-1106
• DOI: 10.1007/s00221-010-2514-x

To better understand normative behavior for quantitative evaluation of motor recovery after injury, we studied arm movements by non-injured Rhesus monkeys during a food-retrieval task. While seated, monkeys reached, grasped, and retrieved food items. We recorded three-dimensional kinematics and muscle activity, and used inverse dynamics to calculate joint moments due to gravity, segmental interactions, and to the muscles and tissues of the arm. Endpoint paths showed curvature in three dimensions, suggesting that maintaining straight paths was not an important constraint. Joint moments were dominated by gravity. Generalized muscle and interaction moments were less than half of the gravitational moments. The relationships between shoulder and elbow resultant moments were linear during both reach and retrieval. Although both reach and retrieval required elbow flexor moments, an elbow extensor (triceps brachii) was active during both phases. Antagonistic muscles of both the elbow and hand were co-activated during reach and retrieval. Joint behavior could be described by lumped-parameter models analogous to torsional springs at the joints. Minor alterations to joint quasi-stiffness properties, aided by interaction moments, result in reciprocal movements that evolve under the influence of gravity. The strategies identified in monkeys to reach, grasp, and retrieve items will allow the quantification of prehension during recovery after a spinal cord injury and the effectiveness of therapeutic interventions.