Motor Cortex

Publisher Summary The cortical structures most involved in motor control in mice and other rodents include a primary motor area, M1 and a secondary motor area, M2. Somatosensory cortex is involved in motor functions in all mammals. In mice and rats, the extent of such involvement is more notable than in most placental mammals, thus granular primary somatosensory cortex (S1) and the associated dysgranular cortex have been commonly included in “sensorimotor” cortex of rodents. Primary motor cortex of mammals can be defined by a number of characteristics, including a relative location in frontal cortex, an agranular type of cytoarchitecture, a systematic representation of the movements of contralateral body parts that can be revealed by electrical stimulation, and a specific pattern of connections with other parts of the nervous system, including the ventrolateral posterior nucleus of the motor thalamus. The anterior cingulate cortex in primates has several motor areas where movements can be evoked by electrical stimulation, and with topographic connections with motor and premotor areas of cortex and projections to the spinal cord. Experiments that examine the effects of motor cortex lesions on behavior most often use rats. This is likely due to their larger size and ease of handing relative to mice. Mice also tend to show increased spontaneous locomotor activity compared to larger rodents, which can make sensorimotor tasks more difficult to evaluate in this species. Epilepsy is a common neurological disorder, characterized by a low threshold for recurrent seizures, where seizures are defined as the excessive, synchronous discharge of aggregates of neurons.