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Functions of basal ganglia:

1) Help to plan and control complex patterns
of muscle movement.
2) Help in controlling relative intensities of the
separate movements, directions of
movements, and sequencing of multiple
successive and parallel movements for
achieving specific complicated motor goals.

The white areas are made up of the axons of the
neurons, and the gray areas are made up of the
nuclei of the neurons. The gray matter is the
thinking part.

All of these structures of the basal ganglia are
related with the movement. For example, the
substantia nigra is related with Parkinson’s disease.

1. THE CEREBELLUM.

1.1. Motor functions of the cerebellum.

 The cerebellum is involved in rapid muscular activities such as running, typing, playing the
piano, and talking.
 Electrical excitation of the cerebellum does not cause any conscious sensation and
rarely causes any motor movement. But removal of the cerebellum causes body
movements to become highly abnormal (total incoordination even though there’s no
muscular paralysis).
 The cerebellum helps to sequence the motor activities and also monitors and makes
corrective adjustments in the body’s motor activities while they are being executed so that
they will conform to the motor signals directed by the cerebral motor cortex and other parts of
the brain. This means that the cerebellum helps to provide smooth and coordinated body
movements.
 The cerebellum receives continuously information from: (1) the brain motor control areas
about the sequence of muscle contractions and (2) the peripheral parts of the body (such as
sensory receptors, proprioceptors, muscle spindle…) about sensory information related with
sequential changes in the status of each part of the body (position, rate of movement…).
 The cerebellum then compares the actual movements as described by the peripheral
sensory feedback information with the movements intended by the motor system and,
if they don’t compare favourably, it sends instantaneous subconscious corrective
signals to specific muscles.
 The cerebellum also aids the cerebral cortex in planning the next sequential movement a
fraction of a second in advance while the current movement is still being executed. The
movement has to be ordered before it takes place because it takes time (the neurons synapse,
then the signal goes to the muscle…).
 But when a movement does not occur exactly as intended, the cerebellar circuit learns
to make a better regulation of the movement the next time (the cerebellum does an
rearrangement) due to: changes that occur in the excitability of appropriate cerebellar
neurons, thus bringing subsequent muscle contractions into better correspondence
with the intended movements.

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