Located in the medulla oblongata

Medulla oblongata

The medulla oblongata is the lower half of the brainstem. In discussions of neurology and similar contexts where no ambiguity will result, it is often referred to as simply the medulla...

, the gracile nucleus is one of the dorsal column nuclei

Dorsal column nuclei

In neuroanatomy, the dorsal column nuclei are a pair of nuclei in the brainstem. The name refers collectively to the cuneate nucleus and gracile nucleus, which are present at the junction between the spinal cord and the medulla oblongata...

 that participate in the sensation of fine touch and proprioception

Proprioception

Proprioception , from Latin proprius, meaning "one's own" and perception, is the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement...

 of the lower body (legs and trunk). It contains second-order 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 of the dorsal column-medial lemniscus system, which receive inputs from sensory neuron

Sensory neuron

Sensory neurons are typically classified as the neurons responsible for converting external stimuli from the environment into internal stimuli. They are activated by sensory input , and send projections into the central nervous system that convey sensory information to the brain or spinal cord...

s of the dorsal root ganglia and send 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 that synapse in the thalamus

Thalamus

The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...

.

The 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 contained within the nucleus

Nucleus (neuroanatomy)

In neuroanatomy, a nucleus is a brain structure consisting of a relatively compact cluster of neurons. It is one of the two most common forms of nerve cell organization, the other being layered structures such as the cerebral cortex or cerebellar cortex. In anatomical sections, a nucleus shows up...

 form a visible bump called the gracile tubercle on the posterior side of the closed medulla at the floor of the fourth ventricle

Fourth ventricle

The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ventricle...

.

The gracile nucleus and fasciculus

Fasciculus gracilis

The fasciculus gracilis is a bundle of axon fibres in the posterior column of the spinal cord and carries information from the middle thoracic and lower limbs of the body...

 carry epicritic, kinesthetic, and conscious proprioceptive information from the lower part of the body (below the level of T6 in the spinal cord). The counterpart to the gracile nucleus and fasciculus is the cuneate nucleus

Cuneate nucleus

One of the dorsal column nuclei, the cuneate nucleus is a wedge-shaped nucleus in the closed part of the medulla oblongata. It contains cells that give rise to the cuneate tubercle, visible on the posterior aspect of the medulla...

 and fasciculus

Fasciculus cuneatus

The fasciculus cuneatus is a tract of nerves in the spinal cord which primarily transmits information from the arms...

, which carries the same type of information, but from the upper body (above T6, excepting the face

Face

The face is a central sense organ complex, for those animals that have one, normally on the ventral surface of the head, and can, depending on the definition in the human case, include the hair, forehead, eyebrow, eyelashes, eyes, nose, ears, cheeks, mouth, lips, philtrum, temple, teeth, skin, and...

 and ear

Ear

The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....

 - the information from the face and ear is carried by the principal sensory nucleus of trigeminal nerve).

External links

• NIF Search - Gracile Nucleus via the Neuroscience Information Framework
  Neuroscience Information Framework
  The 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:...