User:Neuroschizl/Spinal nucleus of the bulbocavernosus



The spinal nucleus of the bulbocavernosus (SNB) is a motor neuron pool located in the caudal spinal cord of mammals. The axons of the SNB control two muscles that innervate the base of the penis, the bulbocavernosus and the levator ani. Though the term SNB refers specifically to the motor neuron nucleus, the term is often used to describe the complete neuromuscular system (both the motor neurons and the muscles).

The SNB system has been used extensively as a model to understand mammalian sexual differentiation. The system is present at birth in both males and females, but degenerates in females shortly after birth. This degeneration is due to the lack of androgens. Thus, the SNB system has proved a remarkable model for investigating the role of sex steroids (i.e. androgens) in sexual differentiation.

Discovery
The spinal nucleus of the bulbocavernosus was discovery by Stephen Marc Breedlove, PhD, when he was a graduate student in the laboratory of Arthur Arnold, PhD. The discovery was published in the journal Science in 1980.