Download Application Six - Sheila Tooker Impey

Running head: Effects of CVA on the Precentral Gyrus
Effects of a Cerebrovascular Accident on the Precentral Gyrus
Sheila Impey
PSYC-4002- Brain and Behavior
January 25, 2012
Walden University
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Effects of CVA on the Precentral Gyrus
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Effects of a Cerebrovascular Accident on the Precentral Gyrus
Male patient of, 59 years of age, presents with a stroke where a small blood clot became
lodged in one of the vessels serving the right side of brain. Said blood clot occluded the blood
flow to a portion of his right precentral gyrus resulting in neural damage localized to that area.
As a result, the patient is partially paralyzed on the left side of his body. He is able to move his
left leg and walk, and can also move his left arm, but his left hand and the left side of his face are
paralyzed.
Although the blood clot was on the right side of the brain, the patient’s left side was
affected because one side of the brain controls the opposite side of the body. A stroke affecting
one side of the brain will result in neurological complications on the side of the body it affects
(American Heart Association, 2011). The patient cannot move his left hand or the muscles in the
left side of his face, because of the neural damage to the right precentral gyrus which is the
location of the primary motor cortex that controls voluntary movement.
Most normal functioning neurons receive chemical signals from the axon termini of other
neurons (Freeman, 2000). There is then an action potential that reaches a chemical synapse. A
neurotransmitter is then released into the synaptic cleft. The binding of the neurotransmitter to
receptors on the postsynaptic cell changes the ion permeability and thus the electric potential of
the postsynaptic plasma membrane (Freeman, 2000). An Interneuron is connected to multiple
sensory and motor neurons. This allows one sensory neuron to affect multiple motor neurons
meaning that one muscle can be stimulated to contract while another is repressed from
contracting.
The patient is unable to move his hand, not because the motor neurons were damaged,
but because of the damage to neurons that communicate with the motor neurons. The sensory
Effects of CVA on the Precentral Gyrus
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neurons are no longer communicating with the motor neuron. In simpler terms, the phone works
but no one is calling anymore.
The patient is an adult. Adult mammals no longer produce the chemical and molecular
conditions that stimulate and guide neural growth (Garrett, 2011). Although axons do not
regenerate and neuron replacement is limited at best, it is possible for some function recovery
through compensation (Garrett, 2011). This is where the uninjured tissue of the brain takes on
the function of the injured tissue. Terminals and receptors are sprouted in to take on additional
responsibility. It is important that physical therapy be incorporated into the recovery of a stroke
patient because of the synaptic changes that are taking place.
One experimental treatment includes using neuron growth enhancers that counteract the
forces that inhibit growth (Garrett, 2011). There is also controversial research that involves
using stem cells to replace the injured cells. Placing stem cells into the nervous system would
encourage them to replace injured cells because they respond to the chemical changes in their
environment. Both therapies are still being explored and are not readily available.
Effects of CVA on the Precentral Gyrus
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References
American Heart Association. (2011). Effects of stroke. Retrieved from
http://www.strokeassociation.org/STROKEORG/AboutStroke/EffectsofStroke/Effectsof-Stroke_UCM_308534_SubHomePage.jsp
Freeman, W. H. (2000). Overview of neuron structure and function. Retrieved from
National Center for Biotechnology Information, U.S. National Library of Medicine website:
http://www.ncbi.nlm.nih.gov/books/NBK21535/
Garrett, B. (2011). Brain & behavior, an introduction to biological psychology. (3
ed.). Sage Publications, Inc.