|Location||Layer V of Cortex in primary motor cortex|
|Function||excitatory projection neuron to spinal cord|
|Morphology||Multipolar Pyramidal -- some of the longest axons in the body.|
|Presynaptic connections||Superficial cortical layers, premotor area|
|Postsynaptic connections||Ventral horn of the spinal cord|
Betz cells are pyramidal cell neurons located within the fifth layer of the grey matter in the primary motor cortex. They are named after Vladimir Alekseyevich Betz, who described them in his work published in 1874.  These neurons are some of the largest in the central nervous system, sometimes reaching 100 μm in diameter. Betz cells send their axons down to the spinal cord where in humans they synapse directly with anterior horn cells, which in turn synapse directly with their target muscles. While Betz cells have one apical dendrite typical to pyramidal neurons, they have more primary dendritic shafts, and these do not leave the soma only at basal angles but rather branch out from almost any point asymmetrically. These perisomatic and basal dendrites project into all cortical layers, but most of their horizontal arbors populate layers V and VI, some reaching down into the white matter. According to one study, Betz cells represent about 10% of the total pyramidal cell population in layer Vb of the human primary motor cortex.
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- Rivara CB, Sherwood CC, Bouras C, Hof PR. (2003) Stereologic characterization and spatial distribution patterns of Betz cells in the human primary motor cortex. Anat Rec A Discov Mol Cell Evol Biol. 270(2):137-51. PMID 12524689 free fulltext article (PDF) Extended HTML version