Riehle A., Eilon V. (eds.) Motor Cortex in Voluntary Movements: A Distributed System For Distributed Functions

Boca Raton: CRC Press, 2005. — 420 p.Voluntary movement is undoubtedly the overt basis of human behavior. Without movement we cannot walk, nourish ourselves, communicate, or interact with the environment. This is one of the reasons why the motor cortex was one of the first cortical areas to be explored experimentally. Historically, the generation of motor commands was thought to proceed in a rigidly serial and hierarchical fashion. The traditional metaphor of the piano presents the premotor cortex “playing” the upper motoneuron keys of the primary motor cortex (M1), which in turn activate with strict point-to-point connectivity the lower motoneurons of the spinal cord. Years of research have taught us that we may need to reexamine almost all aspects of this model. Both the premotor and the primary motor cortex project directly to the spinal cord in highly complex overlapping patterns, contradicting the simple hierarchical view of motor control. The task of generating and controlling movements appears to be subdivided into a number of subtasks that are accomplished through parallel distributed processing in multiple motor areas. Multiple motor areas may increase the behavioral flexibility by responding in a context-related way to any constraint within the environment. Furthermore, although more and more knowledge is accumulating, there is still an ongoing debate about what is represented in the motor cortex: dynamic parameters (such as specific muscle activation), kinematic parameters of the movement (for example, its direction and speed), or even more abstract parameters such as the context of the movement. Given the great scope of the subject considered here, this book focuses on some new perspectives developed from contemporary monkey and human studies. Moreover, many topics receive very limited treatment.