Neuronal Population Coding of Movement Direction

• Published in: Science (American Association for the Advancement of Science) Vol. 233; no. 4771; pp. 1416 - 1419
• Main Authors: Georgopoulos, Apostolos P., Schwartz, Andrew B., Kettner, Ronald E.
• Format: Journal Article
• Language: English
• Published: Washington, DC The American Association for the Advancement of Science 26.09.1986; American Association for the Advancement of Science
• Subjects: Animal locomotion; Animals; Arm; Arm - innervation; Biological and medical sciences; Biology; Brain; Clouds; Cosine function; Food movements; Fundamental and applied biological sciences. Psychology; Macaca mulatta; Mathematical vectors; Mathematics; Models, Neurological; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Motor cortex; Motor Cortex - physiology; Motor neurons; Motor Neurons - physiology; Multiple regression; Nervous system; Neurons; Neuroscience; Physiological aspects; Vertebrates: nervous system and sense organs; Monkey; Central nervous system; Electrophysiology; Brain (Vertebrata); Mathematics; Direction; Vertebrata; Mammalia; Coding; Motor cortex; Body movement; Primates; Arm; Forelimb
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.3749885

Although individual neurons in the arm area of the primate motor cortex are only broadly tuned to a particular direction in three-dimensional space, the animal can very precisely control the movement of its arm. The direction of movement was found to be uniquely predicted by the action of a population of motor cortical neurons. When individual cells were represented as vectors that make weighted contributions along the axis of their preferred direction (according to changes in their activity during the movement under consideration) the resulting vector sum of all cell vectors (population vector) was in a direction congruent with the direction of movement. This population vector can be monitored during various tasks, and similar measures in other neuronal populations could be of heuristic value where there is a neural representation of variables with vectorial attributes.