Betz cells are pyramidal cellneurons 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.[1] These neurons are some of the largest in the central nervous system, sometimes reaching 100 ?m in diameter.[2] Betz cells send their axons down to the spinal cord where in humans they synapse directly with anterior horncells, 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.[3] 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.[4] According to one study, Betz cells represent about 10% of the total pyramidal cell population in layer Vb of the human primary motor cortex.[5]
References
↑ Betz W. (1874) Anatomischer Nachweis zweier Gehirncentra. Centralblatt für die medizinischen Wissenschaften. 12:578-580, 595-599.
↑ Nolte, J. The Human Brain, 5th ed. Mosby: Missouri; 2002, p.527. ISBN 0-323-01320-1
↑ Braak H, Braak E. (1976) The pyramidal cells of Betz within the cingulate and precentral gigantopyramidal field in the human brain. A Golgi and pigmentarchitectonic study. Cell Tissue Res. 172(1):103-19. PMID 991201
↑ Meyer G. (1987) Forms and spatial arrangement of neurons in the primary motor cortex of man. J Comp Neurol 262:402?428. PMID 3655019
↑ 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
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