Cerebellum

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http://www.healthline.com/human-body-maps/cerebellum

The cerebellum is located behind the top part of the brain stem (where the spinal cord meets the brain) and is made of two hemispheres (halves).

The cerebellum receives information from the sensory systems, the spinal cord, and other parts of the brain and then regulates motor movements. The cerebellum coordinates voluntary movements such as posture, balance, coordination, and speech, resulting in smooth and balanced muscular activity. It is also important for learning motor behaviors.

It is a relatively small portion of the brain -- about ten percent of the total weight, but it contains roughly half of the brain's neurons, specialized cells that transmit information via electrical signals.

The cerebellum is not unique to humans. Evolutionarily speaking, it is an older portion of the brain. It is present in animals that scientists believe existed before humans.

Damage to the cerebellum, while not causing paralysis or intellectual impairment, might lead to a lack of balance, slower movements, and tremors (shaking). Complex physical tasks would become unsteady and halting.

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http://www.neuroskills.com/brain-injury/cerebellum.php

The cerebellum is involved in the coordination of voluntary motor movement, balance and equilibrium and muscle tone. It is located just above the brain stem and toward the back of the brain. It is relatively well protected from trauma compared to the frontal and temporal lobes and brain stem.

Cerebellar injury results in movements that are slow and uncoordinated. Individuals with cerebellar lesions tend to sway and stagger when walking.

Damage to the cerebellum can lead to: 1) loss of coordination of motor movement (asynergia), 2) the inability to judge distance and when to stop (dysmetria), 3) the inability to perform rapid alternating movements (adiadochokinesia), 4) movement tremors (intention tremor), 5) staggering, wide based walking (ataxic gait), 6) tendency toward falling, 7) weak muscles (hypotonia), 8) slurred speech (ataxic dysarthria), and 9) abnormal eye movements (nystagmus)

The cerebellum receives direct information from all the sensory receptors in the head and the limbs and from most areas of the cerebral cortex