Studying motor cortex function using the rodent vibrissal system

Abstract The function of the mammalian motor cortex was one of the first problems studied in neuroscience. But until today, the major principles of the workings of the motor cortex have remained conjectural. It is clear that motor cortex holds a topographic map of body parts. But does that mean that the motor cortex itself is undertaking the challenging task of converting motor plans (i.e., intended trajectories and effects of actions) into low level motor commands appropriate to drive the muscles? Work of many decades on motor function has revealed the existence of dedicated networks, the so-called central pattern generators (CPGs). Many, if not all of these CPGs, are located subcortically and are likely to be involved in the translation of motor plans into actual muscle contractions. Unfortunately the detailed circuitry and cellular elements of CPGs are only vaguely known. More recent work has elucidated continuous as well as discontinuous (discrete) mapping of the motor cortex to movement. For the quest of understanding motor cortex–CPG interactions, discontinuities are important because they allow us to dissect how neighboring motor cortex sites connect to different CPGs for different purposes—but driving the very same muscles. The rodent whisker motor system is a decidedly modular system. Neighboring cortical areas drive very distinct whisker movements used by the animals in different contexts. We argue that the modularity of the whisker system to...
Source: e-Neuroforum - Category: Neuroscience Source Type: research