Betz cells are upper motor neurons that send their axons down to the spinal cord via the corticospinal tract, where in humans they synapse directly with anterior horncells, which in turn synapse directly with their target muscles. Betz cells are not the sole source of direct connections to those neurons because most of the direct corticomotorneuronal cells are medium or small neurons.[3] While Betz cells have one apical dendrite typical of pyramidal neurons, they have more primary dendritic shafts, which can branch out at almost any point from the soma (cell body).[4] These perisomatic (around the cell body) and basal dendrites project into all cortical layers, but most of their horizontal branches/arbors populate layers V and VI, some reaching down into the white matter.[5] According to one study, Betz cells represent about 10% of the total pyramidal cell population in layer Vb of the human primary motor cortex.[6]
Betz cells are named after Ukrainian scientist Volodymyr Betz, who described them in his work published in 1874.[7]
^Purves, Dale; George J. Augustine; David Fitzpatrick; William C. Hall; Anthony-Samuel LaMantia; James O. McNamara & Leonard E. White (2008). Neuroscience (4th ed.). Sinauer Associates. pp. 432–4. ISBN978-0-87893-697-7.
^Nolte, J. The Human Brain, 5th ed. Mosby: Missouri; 2002, p.527. ISBN0-323-01320-1
^Strick, Peter L.; Dum, Richard P.; Rathelot, Jean-Alban (8 July 2021). "The Cortical Motor Areas and the Emergence of Motor Skills: A Neuroanatomical Perspective". Annual Review of Neuroscience. 44 (1): 425–447. doi:10.1146/annurev-neuro-070918-050216. PMID33863253. S2CID233278281.
^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 and Tissue Research. 172 (1): 103–19. doi:10.1007/bf00226052. PMID991201. S2CID40242681.
^Meyer, G (1987). "Forms and spatial arrangement of neurons in the primary motor cortex of man". The Journal of Comparative Neurology. 262 (3): 402–28. doi:10.1002/cne.902620306. PMID3655019. S2CID45950277.