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This article throws light upon the three main structures of the brain with its clinical considerations.
1. Limbic System:
The C.N.S. localization for emotions, is called the Limbic system by James Paper (1939). The latest models of the limbic system include the amygdala and septal area. Also many parts of the basal ganglia are connected to the limbic system which explains the simultaneous presence of a movement disorder and an emotional disorder in some patients.
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Clinical Considerations:
Important psychological functions like emotions, eating behaviour, sex drive, anger, violence, memory and motivation etc. are associated with various parts of the limbic system. Destruction of both the sides (bilateral) of the amygdala and the temporal lobes produce symptoms like hyper quality and severe docility.
Damage or injury of the amygdala and anterior temporal lobes have been clinically correlated with a number of behaviours in human beings and symptoms similar to schizophrenia, mania and depression. It is also urgent to note that brain trauma and presence of abnormal E.E.G.S. are commonly found in violent and aggressive children and prisoners.
2. Basal Ganglia:
Recent researches suggest that the basal ganglia are involved in certain cerebral disorders including psychosis, depression and dementia.
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Clinical Considerations:
Disorders in the basal ganglia are basically neurological and produce disorders of movement, thought processes, emotion and cognition. Besides the neurological symptoms, psychiatric symptoms in schizophrenics are also observed. Unseated schizophrenic patients show a larger number of movement disorders mat indicate an involvement of the basal ganglia.
Parkinson’s Disease:
Parkinson’s disease (PD) occurs due to the striatal deficiency of dopamine following neuronal degeneration in the brain. Thus, it primarily occurs due to destruction of the dopaminergic cells in the substantia nigra and degeneration of cells in the ventral segmental area and the locus ceruleus.
This leads to tremor, muscle rigidity, stooped posture etc. Hence Parkinson’s disease is characterized by an insidious onset with slowing of voluntary movement, muscular rigidity and postural abnormality. There is imbalance and lack of coordination of movement. It may be caused by encephalitis, carbon monoxide poisoning or head injury.
Depression is a very common syndrome of Parkinson’s patients. The incidence of depression is between 50 per cent to 90 per cent and is more common in males. Dementia which is a symptom of schizophrenia is present in 30 per cent to 80 per cent of the Parkinson’s disease patients.
Basic for the treatment of this disease besides the other techniques, one latest therapy developed by scientists of U.K. is called ‘Activa therapy.’ This revolutionary technique used Medtronic’s brain Pace maker technology to relieve the slowness, stiffness and shaking of the Parkinson’s patients.
Activa therapy can also reduce the duration of dyskinesia, the abnormal involuntary movements that are a common side effects of medication for this disease.
Activa therapy is highly flexible. In this therapy carefully controlled pulses with minimum side effects of electrical stimulation is given to certain specific areas of the brain. This medical device is similar to a cardiac pace maker. This is a very effective new approach to treat the disease, says Dr. Rupam Borgehain, a professor at the Neurology Deptt, Nizam’s Indian Institute of Medical Science.
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According to him Activa therapy is a major breakthrough in the treatment of Parkinson’s disease up until this point, patients relied on medications that may not provide control of symptoms and also may produce significant side effects.
On the other hand Activa therapy is highly flexible. Significant symptom relief can be provided by this technique with minimum side effects. Therapy is reversible i.e., patients can pursue new treatments that may be developed in future.
Huntington’s Disease:
This disease is characterized by dominant movement disorder, deteriorating course of chorea, depression, suicidal tendency, forgetting and psychosis. Psychosis is observed in about 20 per cent of the cases.
A recent development of neuropsychiatry is the application of molecular genetics techniques to Huntington’s disease. Wilson’s disease and Fahr’s Syndrome are also observed because of disorders and injuries in the brain.
3. Hypothalamus and Pituitary:
“The hypothalamus and the Pituitary comprise the master endocrine gland. Thus these two functions as a major integrating and output system for the entire C.N.S.” —Kaplan and Sadok—1987
The hypothalamus not only regulates the endocrine secretion, it is also considered a part of the limbic system and it deals with appetite and sexual regulation.
The hypothalamus and the endocrine system provides special interest to the psychiatrists because of their clinical considerations. Observations indicate that various endocrine disorders have psychiatric symptoms and similarly many psychiatric disorders have endocrine dysfunctions.
According to Kaplan and Sadok, the hypothalamus appears also to have a major role in the centres of biological rhythm and immune system regulation.
Clinical Considerations:
The hypothalamus and pituitary help in the regulation of the endocrine and autonomic nervous system (A.N.S.) and in the control of body temperature, eating behaviour, and sleep wake cycle.
The involvement of the hypothalamus in the A.N.S. involved it in psychosomatic disorders.
Destruction of the ventromedial hypothalamus results in hyperphragia and obesity. Destruction of lateral hypothalamus leads to anorexia and starvation. The limbic system and the prefrontal cortex are also involved in eating behaviour.
Clinical Considerations of the Thalamus:
The thalamus has a critical role in the perception of pain. Tumours or vascular lesions of the thalamus can produce severe pain symptoms. Clinical Considerations Relating to Reticular Activating System The reticular activating system is a closely organised network of neurons running up the midline of the brainstem.
These neurons receive information from the ascending sensory neurons; cerebellum, basal ganglia, hypothalamus and cerebral cortex and send projections to the hypothalamus and spinal cord.
Stimulation of the reticular activating system activates the cortex into a state of alert wakefulness. Disorder and pathology in this area lead to psychiatric disorders involving deterioration and impairment of drive motivational level and level of arousal.
Brain imaging techniques like Magnetic Resonance (M.R.) Computed tomography (C.T.) have helped psychiatrists in their investigations and research in the area of clinical psychology.