Extrapyramidal system

The portion of the central nervous system (CNS) responsible for coordinating and integrating various aspects of motor behavior or body movements. This system is usually described in terms of cortical, basal ganglia, and midbrain levels of integration.

The portion of the central nervous system responsible for coordinating and integrating various aspects of motor behavior or body movements.

A motor system which carries motor nerves outside the pyramidal system.

The portion of the central nervous system that affects electrical impulses sent from the brain to the skeletal muscles, influencing large muscle movements such as walking. The system connects nerves in the cerebrum with the basal ganglia (structures deep within the brain that coordinate voluntary muscle movement) and parts of the brain stem.

The system of nerve tracts and pathways connecting the cerebral cortex, basal ganglia, thalamus, cerebellum, reticular formation, and spinal neurons in complex circuits not included in the pyramidal system. The extrapyramidal system is mainly concerned with the regulation of stereotyped reflex muscular movements.

This is a complex part of the nervous system, extending from the cortex to the medulla in the brain, from which emerge descending spinal pathways which influence voluntary motor activity throughout the body. Although the normal functions of the system are poorly understood, there are characteristic signs of an extrapyramidal lesion. These include disturbance of voluntary movements, notably slowness and ‘poverty’ of movement; disturbance of muscular tone, which may be increased or decreased; and involuntary movements, such as a tremor, irregular jerking movements, or slow writhing movements.