Cables vs. networks: old and new views on the function of motor cortex
Early in the physiological study of the motor cortex, one experimental question began to dominate the research. How are points in cortex connected to muscles? The question fosters a simplistic, feed-forward view of motor cortex in which its intrinsic processing is ignored and its function is assumed to be defined almost entirely by the cables that run down to the spinal cord, relay onto motor neurons, and thus cause muscle contraction. This perspective still pervades almost all modern thinking about the motor cortex. As a result, a more realistic view of motor cortex as a control network has been hindered. The study by Capaday et al. (2011), examining the lateral interactions among neurons in motor cortex, represents an important step beyond the limited muscle-map conception and toward a better understanding of the processing network within the cortex itself.