[1][2] Like alpha motor neurons, their cell bodies are located in the anterior grey column of the spinal cord.

Muscle spindles are the sensory receptors located within muscles that allow communication to the spinal cord and brain with information of where the body is in space (proprioception) and how fast body limbs are moving with relation to space (velocity).

The spindle is innervated by type Ia sensory fiber that go on to synapse with alpha motor neurons, completing the gamma-loop.

The parallel pulling keeps muscle spindles taut and readily able to detect minute changes in stretch.

Gamma motor neurons are the efferent (sending signals away from the central nervous system) part of the fusimotor system, whereas muscle spindles are the afferent part, as they send signals relaying information from muscles toward the spinal cord and brain.

The sensitivity of sensory endings (primary and secondary endings - Ia, II) of the muscle spindle are based on the level of gamma bias (i.e. how much background level of gamma motor neuron discharge is taking place.

Dynamic gamma motor neurons alter muscle spindle sensitivity and increases its discharge in response to velocity, the rate of change, of muscle length rather than simply the magnitude as it is with static gamma motor neurons.

Therefore, this type of gamma motor neuron can be used for activities requiring quick changes in muscle length to adjust such as balancing on a rail.

Sonic hedgehog genes (Shh) are an important part of the development process that is secreted by the notochord creating gradients of concentrations.

[10] Wnt7A is a secreted signaling molecule selectively in gamma motor neurons by embryonic day 17.5 of mice.

In addition, knockout mice without this serotonin receptor exhibited more coordination on a balance beam task, suggesting that less activation of motor neurons by Ia afferents during movement could reduce the unnecessary excess of muscle output.

[13] Osteopontin, a protein also expressed in bones, hence the "osteo-" prefix, is a marker for alpha motor neurons.

Its purpose is to maintain posture and assist in quicker movements, since if muscles were completely loose, then more neuronal firing would need to take place.

The amount of tension in the muscles depends primarily on the resting level discharge of alpha motor neurons and Ia spindle afferents.

For example, if a patient has over active gamma motor neurons, there will be a resistance to passive movement causing stiffness, also called spasticity.

[7] Gamma motor neurons assist in keeping the muscle spindle taut, thus adjusting sensitivity.

Therefore, if proper gamma motor neuronal firing does not occur, muscle movement can be adversely affected.

Fine motor skills such as movements with the fingers and eyes are affected most, since any lack of tautness within the muscle spindle hinders its ability to detect the amount of stretch through the sensory endings.

In clinical settings, it is possible to test whether someone has an abnormally low or high gamma gain simply by moving the patient's arm.

Gamma gain is the process where acceleration, velocity, and length of muscle changes are scaled up equally, enabling more accurate movements to take place in the appropriate situation.

Oscilloscopes can be used to measure action potentials of an axon from a motor neuron in order to assess general muscle activity.