for "man") to refer to it. It is perhaps for this reason that his work has become so popular in neuroscience. The motor cortex map A simple view, that is almost certainly too limited and that dates back to the earliest work on the motor cortex, is that neurons in the motor cortex control movement by a feed-forward direct pathway. In that view, a neuron in the motor cortex sends an axon or projection to the spinal cord and forms a synapse on a motor neuron. The motor neuron sends an electrical impulse to a muscle. When the neuron in the cortex becomes active, it causes a muscle contraction. The greater the activity in the motor cortex, the stronger the muscle force. Each point in the motor cortex controls a muscle or a small group of related muscles. This description is only partly correct. Most neurons in the motor cortex that project to the spinal cord synapse on interneuron circuitry in the spinal cord, not directly onto motor neurons. One suggestion is that the direct, cortico-motoneuronal projections are a specialization that allows for the fine control of the fingers. The view that each point in the motor cortex controls a muscle or a limited set of related muscles was debated over the entire history of research on the motor cortex, and was suggested in its strongest and most extreme form by Asanuma on the basis of experiments in cats and monkeys using electrical stimulation. However, almost every other experiment to examine the map, including the classic work of Ferrier and of Penfield showed that each point in the motor cortex influences a range of muscles and joints. The map is greatly overlapping. The overlap in the map is generally greater in the premotor cortex and supplementary motor cortex, but even the map in the primary motor cortex controls muscles in an extensively overlapped manner. Many studies have demonstrated the overlapping representation of muscles in the motor cortex. It is believed that as an animal learns a complex movement repertoire, the motor cortex gradually comes to coordinate among muscles. The clearest example of the coordination of muscles into complex movement in the motor cortex comes from the work of Graziano and colleagues on the monkey brain. They used electrical stimulation on a behavioral time scale, such as for half a second instead of the more typical hundredth of a second. They