In
anatomy, the
extrapyramidal system is a
neural network that is part of the
motor system causing involuntary movements. The system is called "extrapyramidal" to distinguish it from the tracts of the motor cortex that reach their targets by traveling through the "
pyramids" of the
medulla. The
pyramidal pathways (
corticospinal and some
corticobulbar tracts) may directly innervate motor neurons of the spinal cord or brainstem (
anterior (ventral) horn cells or certain cranial nerve nuclei), whereas the extrapyramidal system centers on the modulation and regulation (indirect control) of anterior (ventral) horn cells.