The Cerebellum

Cerebellum

The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...

 has four deep cerebellar nuclei

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...

 embedded in the white matter in its center.

Inputs

These nuclei receive inhibitory

Inhibitory postsynaptic potential

An inhibitory postsynaptic potential is a synaptic potential that decreases the chance that a future action potential will occur in a postsynaptic neuron or α-motoneuron...

 (GABA

Gabâ

Gabâ or gabaa, for the people in many parts of the Philippines), is the concept of a non-human and non-divine, imminent retribution. A sort of negative karma, it is generally seen as an evil effect on a person because of their wrongdoings or transgressions...

ergic) inputs from Purkinje cells in the cerebellar cortex and excitatory

Excitatory postsynaptic potential

In neuroscience, an excitatory postsynaptic potential is a temporary depolarization of postsynaptic membrane potential caused by the flow of positively charged ions into the postsynaptic cell as a result of opening of ligand-sensitive channels...

 (glutamatergic) inputs from mossy fiber and climbing fiber

Climbing fiber

Climbing fibers are the name given to a series of neuronal projections from the inferior olivary nucleus located in the medulla oblongata.These axons pass through the pons and enter the cerebellum via the inferior cerebellar peduncle where they form synapses with the deep cerebellar nuclei and...

 pathways. Most output fibers of the cerebellum originate from these nuclei. One exception is that fibers from the flocculonodular lobe

Flocculonodular lobe

The flocculonodular lobe is a lobe of the cerebellum consisting of the nodule and the flocculus.It is closely associated with the vestibulocerebellum. This lobe is involved in the maintenance of equilibrium.-External links:...

 synapse directly on vestibular nuclei

Vestibular nuclei

The vestibular nuclei are the cranial nuclei for the vestibular nerve.In Terminologia Anatomica they are grouped in both the pons and medulla.-Subnuclei:There are 4 subnuclei; they are situated at the floor of the fourth ventricle....

 without first passing through the deep cerebellar nuclei. The vestibular nuclei in the brainstem are analogous structures to the deep nuclei, since they receive both mossy fiber and Purkinje cell inputs.

Specific nuclei

From lateral to medial, the four deep cerebellar nuclei are the dentate

Dentate nucleus

The dentate nucleus is located within the deep white matter of each cerebellar hemisphere, and it is the largest single structure linking the cerebellum to the rest of the brain. It is the largest and most lateral, or farthest from the midline, of the four pairs of deep cerebellar nuclei, the...

, emboliform, globose

Globose nucleus

The globose nucleus is one of the deep cerebellar nuclei. It is located medial to the emboliform nucleus and lateral to the fastigial nucleus. This nucleus contains primarily large and small multipolar neurons....

, and fastigii. An easy mnemonic

Mnemonic

A mnemonic , or mnemonic device, is any learning technique that aids memory. To improve long term memory, mnemonic systems are used to make memorization easier. Commonly encountered mnemonics are often verbal, such as a very short poem or a special word used to help a person remember something,...

 device to remember their names and positions relative to the midline is the phrase "Don't Eat Greasy Food," where each letter indicates the lateral to medial location in the cerebellar white matter, and the Too reflects the presence of two globus nuclei on each side.

Some animals, including humans, do not have distinct emboliform and globose nuclei, instead having a single, fused nucleus interpositus (interposed nucleus). In animals with distinct emboliform and globose nuclei, the term interposed nucleus

Interposed nucleus

The interposed nucleus is a deep nucleus of the cerebellum and is composed of the globose nuclei and the emboliform nuclei. It is located in the roof of the fourth ventricle, lateral to the fastigial nucleus...

 is often used to refer collectively to these two nuclei.

Somatotopy

In general, each pair of deep nuclei is associated with a corresponding region of cerebellar surface anatomy.

• The dentate nuclei are deep within the lateral hemispheres,
• the interposed nuclei are located in the paravermal (intermediate) zone,
• and the fastigial nuclei are in the vermis.

These structural relationships are generally maintained in the neuronal connections between the nuclei and associated cerebellar cortex,

• with the dentate nucleus receiving most of its connections from the lateral hemispheres,
• the interposed nuclei receiving inputs mostly from the paravermis,
• and the fastigial nucleus receiving primarily afferents from the vermis.

External links

• http://www.mona.uwi.edu/fpas/courses/physiology/neurophysiology/Cerebellum.htm