Betz cells

Betz cells or Betz's cells are a type of neuron found in the human brain's primary motor cortex. Named after Ukrainian scientist Vladimir Betz, who discovered them in 1874, these cells are the largest pyramidal neurons in the brain and play a crucial role in sending signals to the spinal cord to initiate voluntary muscle movement.

Anatomy and Function

Betz cells are located in the fifth layer of the grey matter in the primary motor cortex, also known as Brodmann area 4. They are characterized by their large size, with cell bodies measuring up to 100 micrometers in diameter.

These cells have a pyramidal shape, with a single large dendrite extending from the apex towards the surface of the cortex, and multiple smaller dendrites branching out from the base. The axon of a Betz cell travels down through the white matter of the brain, into the spinal cord, where it forms synapses with lower motor neurons in the anterior horn.

The primary function of Betz cells is to transmit motor commands from the brain to the muscles. When a voluntary movement is initiated, signals are sent from the premotor cortex to the Betz cells in the primary motor cortex. These cells then send a strong, fast signal down their axons to the lower motor neurons in the spinal cord, which in turn transmit the signal to the relevant muscles.

Clinical Significance

Damage to Betz cells can result in a variety of motor disorders. For example, in amyotrophic lateral sclerosis (ALS), these cells are among the first to degenerate, leading to progressive muscle weakness and paralysis. Similarly, in primary lateral sclerosis (PLS), a rare neurological disorder, Betz cells are selectively damaged, resulting in stiffness and difficulty moving.

Research into Betz cells may also provide insights into other neurological conditions. For instance, some studies suggest that changes in the size and number of Betz cells may be associated with schizophrenia and autism.

See Also

• Motor neuron
• Motor cortex
• Neuroanatomy
• Neuroscience