Betz cell
Encyclopedia
Betz cells are pyramidal cell
neuron
s located within the fifth layer of the grey matter
in the primary motor cortex
, M1. They are named after Vladimir Alekseyevich Betz, who described them in his work published in 1874. These neurons are the largest in the central nervous system
, sometimes reaching 100 μm in diameter. Betz cells send their axon
s down to the spinal cord where in human
s they synapse
directly with anterior horn
cells
, which in turn synapse directly with their target muscle
s. 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 dendrite
s 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.
Pyramidal cell
Pyramidal neurons are a type of neuron found in areas of the brain including cerebral cortex, the hippocampus, and in the amygdala. Pyramidal neurons are the primary excitation units of the mammalian prefrontal cortex and the corticospinal tract. Pyramidal neurons were first discovered and...
neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
s located within the fifth layer of the grey matter
Grey matter
Grey matter is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil , glial cells and capillaries. Grey matter contains neural cell bodies, in contrast to white matter, which does not and mostly contains myelinated axon tracts...
in the primary motor cortex
Primary motor cortex
The primary motor cortex is a brain region that in humans is located in the posterior portion of the frontal lobe. Itworks in association with pre-motor areas to plan and execute movements. M1 contains large neurons known as Betz cells, which send long axons down the spinal cord to synapse onto...
, M1. They are named after Vladimir Alekseyevich Betz, who described them in his work published in 1874. These neurons are the largest in the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
, sometimes reaching 100 μm in diameter. Betz cells send their axon
Axon
An axon is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma....
s down to the spinal cord where in human
Human
Humans are the only living species in the Homo genus...
s they synapse
Synapse
In the nervous system, a synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell...
directly with anterior horn
Anterior horn (spinal cord)
The anterior horn of the spinal cord is the ventral grey matter section of the spinal cord. The anterior horn contains motor neurons that affect the axial muscles while the posterior horn receives information regarding touch and sensation...
cells
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
, which in turn synapse directly with their target muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
s. 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 dendrite
Basal dendrite
A basal dendrite is a dendrite that emerges from the base of a pyramidal cell that receives information from nearby neurons and passes it to the soma, or cell body....
s 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.
External links
- NIF Search - Betz Cell via the Neuroscience Information FrameworkNeuroscience Information FrameworkThe Neuroscience Information Framework is a repository of global neuroscience web resources, including experimental, clinical, and translational neuroscience databases, knowledge bases, atlases, and genetic/genomic resources.-Description:...