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The corticobulbar (or corticonuclear) tract is a two-neuron white matter motor pathway connecting the motor cortex in the cerebral cortex to the medullary pyramids, which are part of the brainstem's medulla oblongata (also called "bulbar") region, and are primarily involved in carrying the motor function of the non-oculomotor cranial nerves, like muscles of the face, head and neck.
The pyramidal tracts include both the corticobulbar tract and the corticospinal tract.These are aggregations of efferent nerve fibers from the upper motor neurons that travel from the cerebral cortex and terminate either in the brainstem (corticobulbar) or spinal cord (corticospinal) and are involved in the control of motor functions of the body.
The pyramidal tracts (corticospinal tract and 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.
The rubrospinal tract is one of the descending tracts of the spinal cord. It is a motor control pathway that originates in the red nucleus. [1] It is a part of the lateral indirect extrapyramidal tract. The rubrospinal tract fibers are efferent nerve fibers from the magnocellular part of the red nucleus.
The other output (the rubrospinal projection) goes to the rhombencephalic reticular formation and spinal cord of the opposite side, making up the rubrospinal tract, which runs ventral to the lateral corticospinal tract. As stated earlier, the rubrospinal tract is more important in non-primate species: in primates, because of the well-developed ...
The rubro-olivary tract (rubroolivary fibers) [1] is a tract which connects the inferior olivary nucleus, and the parvocellular red nucleus. It is hypothesized that it uses both the corticospinal and rubrospinal tracts .
The cell bodies of Betz cell neurons are the largest in the brain, approaching nearly 0.1 mm in diameter. The axons of the upper motor neurons project out of the precentral gyrus travelling through to the brainstem, where they will decussate (intersect) within the lower medulla oblongata to form the lateral corticospinal tract on each side of ...
PIR cells tend to project upon the cerebral cortex and terminate in an organized topographic manner in specifically localized zones (in deep layer III and in the middle layer IV). In contrast, CIR cells have dispersed projections wherein various adjacent cells connect to non-specific different cortical areas.