Functional Architecture of Directional Tuning in the Primate Motor Cortex During 3D Reaching

© Oxford University Press, 2013. The primary motor cortex (M1) maintains a dynamic representation of higher-order features of movement, most notably the direction of reaching. In fact, almost half of the cells in the arm region of the motor cortex show an orderly variation in activity as a function of the movement direction, with a peak of activity in their preferred direction (PD), and progressively lower rates for movements farther and farther away from the PD. This orderly variation of cell activity is characterized by the directional tuning curve that can be approximated by a cosine function. This chapter addresses the question: What are the anatomical bases for directional tuning? The microand macro-anatomical architecture of directional tuning in the motor cortex are discussed.