Central Control of Movements in Exercise and Sport
by Alastair Riley
The central nervous system (CNS) coordinates the activity
of all parts of the body. The human brain is the centre of
the human nervous system; it is arguable one of the most complex
organ in the body. The CNS also consists of the spinal cord.
The brain is protected by the skull and the spinal cord by
the vertebrae.
The cerebellum is a small region of the brain that plays
an important role in coordination, sensory perception and
motor control. The cerebral motor cortex, spinocerebrallar
tract and cerebellum are linked by neural pathways which allow
for information to reach the muscles causing them to move.
The cerebellum integrates these pathways using the constant
feedback to enhance motor activity. (Fine et al 2002)
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Voluntary
and involuntary movements are produced by spatial and temporal patterns
of muscular contractions of the brain and spinal cord. Hogan (1984)
describes voluntary movement as being able to make the smoothest
movement possible under the circumstances. Motor neurons are discharged
and these innervate the mechanical response of muscles. Central
control incorporates the sensory inputs from the eyes, ears and
from the skin, muscle and joint receptors that are able to characterize
the location, size, shape, weight and texture of the object that
forms the goal of movement.
The different parts of the CNS concerned with movement control
are organised in a distributed fashion and are known to act in parallel.
The motor pathways from the brain stem,midbrain and cerebral cortex
directly influence groups of interneurons and motor neurons that
are concerned with trunk, shoulder, pelvic girdle and distal limb
movments (Macaluso & Driver 2005)
A ‘loop’ is where an output of a particular structure
is sent to a number of other regions from which process the information
and send it back, directly and indirectly. The two most important
‘loops’ are those linking the areas of cerebral cortex
concerned with movement with the cerebellum and basal ganglia. There
is a detectable activity in the brain as much as a whole second
before the onset of voluntary movement. This is a relatively long
time delay with respect to nerve conduction velocity. This allows
time for processing the information.
References
Fine EJ, Ionita CC, Lohr L (2002). "The history of the development
of the cerebellar examination". Semin Neurol 22 (4): 375–84
Hogan N. (1984) An Organising Principle for a Class of Voluntary
Movement. The Journal of Neuroscience Vol. 4, No. 11, pp. 2745-2754
Macaluso E, Driver J. (2005). "Multisensory spatial interactions:
a window onto functional integration in the human brain.".
Trends in Neurosciences 28: 263-271.
Porter, R. and Lemon, R. N. (1993). Corticospinal function and
voluntary movement. Oxford University Press.
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