Cerebellum

The Cerebellum As part of the vertebrate brain, it has many important functions in controlling motor skills. Damage to the cerebellum manifests itself in specific symptoms depending on the affected area and the extent.

What is the cerebellum

Schematic representation of the anatomy and structure of the brain. Click to enlarge.

The Cerebellum, Latin Cerebellum, is located in humans below the cerebrum and behind the brain stem in the posterior fossa. It is the second largest part of the brain after the cerebrum, but has a higher cell density and significantly more neurons than the cerebrum.

Although the cerebellum has only about 10 percent of the weight of the cerebrum, numerous fine twists make it a surface area that corresponds to 50 to 75 percent of that of the cerebrum. It is through the cerebellar tent, the so-called Tentorium cerebelli, separated from the cerebrum. The cerebellum is connected to the brain stem via three cerebellar stalks, the Pedunculus cerebellaris inferior, Pedunculus cerebellaris medius and the Pedunculus cerebellaris superior, connected. The cerebellum fulfills important functions in the coordination and fine-tuning of the body's motion sequences and in learning processes.

Anatomy & structure

The cerebellum consists of two hemispheres, which are located on either side of the so-called worm, Latin Vermis, bulge. The outer layer of the cerebellum is called the cortex or cortex. Inside the cerebellum is a white matter called the medulla or medulla. To increase the surface area, the cerebellum's cortex contains leaf-shaped bulges, the so-called Folia cerebelli, and is of furrows that Cerebellar fissures, streaked. The two hemispheres are anatomically divided into three main lobes by two furrows. These are called Anterior cerebellar lobe, Posterior cerebellar lobe and Flocculonodular lobe designated. However, the cerebellum can also be functionally divided into three areas: The Vestibulocerebellum is connected to the organ of equilibrium and anatomically corresponds to the flocculonodular lobe. The Spinocerebellum receives information from the spinal cord and corresponds to that Anterior lobe. The Pontocerebellum is connected to the cerebrum by fibers and corresponds to the Posterior lobe.

Function & tasks

The cerebellum works unconsciously, conscious control is not possible. The main task of the cerebellum is to control motor skills. The cerebellum also plays an important role in learning how to move. However, researchers now also assume that the cerebellum is involved in cognitive processes such as communication, social behavior and visual perception.

In addition, an activation of the cerebellum in various other tasks such as short-term memory, controlling impulsive behavior, pain, hunger and shortness of breath and other activities could be shown. In contrast to the motor functions, the precise tasks of the cerebellum have not yet been clarified in detail. Different areas of the cerebellum perform different tasks for motor skills.

The vestibulocerebellum controls the holding and supporting motor skills. It is also responsible for fine-tuning the movements of the eyes. It receives the necessary information about the position of the body and the movement through the balance organ. The spinocerebellum is responsible for standing, walking and supporting motor skills.

It also takes on the tasks of target motor skills and the execution of movements. As a result, a movement can proceed as planned and targets, for example when reaching for objects, can be hit exactly. In addition, the spinocerebellum is important for the coordination of facial and larynx muscles, which are required for speaking. It gets its information through fibers of the spinal cord.

The pontocerebellum, the largest part of the cerebellum, is responsible for the detailed planning and coordination of movements. It further develops movement drafts, coordinates and modulates them or corrects movement planning. It gets its information via the so-called bridge, a section of the brain stem.

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Illnesses & ailments

Various diseases can damage the cerebellum or cause it to malfunction. These include brain tumors, abscesses, inflammations or metabolic diseases. Poisoning, for example from alcohol abuse, can affect the cerebellum just as much as injuries from an accident or genetic diseases.

Malfunction of the cerebellum usually results in problems with motor skills, the symptoms of which depend on the location in the cerebellum and the size of the affected area. The symptoms are often grouped under the term ataxia. With ataxia, coordination of movements and posture are disturbed. Balance problems arise and the gait can be unsteady. Movements are uncontrolled and often go beyond the goal.

If only one side of the body is affected by the ataxia, it is referred to as hemiataxia. In an asynergy, coordination is also affected. Different muscle groups cannot work together properly, especially with finer movements. In the case of dysdiadochokinesis, coordination skills are reduced, and a rapid sequence of antagonistic movements can no longer be performed correctly.

In the case of functional disorders of the cerebellum, disorders of the gaze stabilization with eye tremors, the so-called nystagmus, and saccaded gaze sequences can occur. In the saccaded sequence of gazes, the eyes do not move smoothly when looking quickly at one side, but pause briefly in between before moving further to the side. Muscle tension can be reduced, so that the entire body appears limp, or an intention tremor occurs, which is particularly evident in trembling hands when grasping objects.

Another possible symptom of cerebellar damage is bumpy and unclear speech because the muscles needed to speak cannot be fine-tuned for some cerebellar damage.