Topic: replies
Pages: 3, Double spaced
Sources: 1
Order type: Essay
Subject: Medicine and Health
Style: APA
Language: English (U.S.)
Order Description
each reply between 150- 200 words
Discussion
Basal ganglia are important for properly directing motor commands to and from the cerebral cortex. The neuronal firing from the basal ganglia prior to initiation of movement has led to the concept that basal ganglia are involved in planning and programming of the movements where abstract thought is converted into voluntary actions (Nelson and Kreitzer, 2014). Therefore, it controls and then regulates the motor activities from the motor and premotor cortex, causing a smooth fine-tuned output of the voluntary motor function intended (Lanciego, Luquin and Obeso, 2012). Cerebellum does not initiate the movements but with the input from the spinal cord and the cerebral cortex, the cerebellum integrates these inputs to fine tune the motor activity.
Due to the damage of the basal ganglia, few pathological processes can occur. Parkinson’s disease and Huntington’s disease are the most common pathologies. In the Parkinson’s disease, there is a gradual loss of dopaminergic neurons from the substancia nigra of the basal ganglia. Dopamine is an inhibitory neurotransmitter. The motor output from the cerebral cortex is directed via global palidus and pars reticulate of the substancia nigra which has an inhibitory effect on the thalamocortical pathway. Due to the deficiency of the inhibitory neurotransmitter dopamine, the inhibitory action on the thalamocortical pathway is reduced causing hyper-kinetic movement, exaggerated movements, and tremors (Magrinelli et al., 2017). Cerebellar ataxia is a disorder of the cerebellum. This occurs due to a lesion of the cerebellum and causes abnormal balance, and inability to maintain the posture. Due to the lesions in the cerebellum, the neural sensory inputs from the cerebral cortex and the spinal cord cannot be properly integrated and this cannot fine tune the movements. This lead to the loss of the balance and inability to maintain posture. Articulation of the speech can also be affected causing slurred speech (Diener, Timmann and Jueptner, 1996).
References:
Nelson, A. and Kreitzer, A. (2014). Reassessing Models of Basal Ganglia Function and Dysfunction. Annual Review of Neuroscience, 37(1), pp.117-135.
Lanciego, J., Luquin, N. and Obeso, J. (2012). Functional Neuroanatomy of the Basal Ganglia. Cold Spring Harbor Perspectives in Medicine, 2(12), pp.a009621-a009621.
Magrinelli, F., Picelli, A., Tocco, P., Federico, A., Roncari, L., Smania, N., Zanette, G. and Tamburin, S. (2017). Pathophysiology of Motor Dysfunction in Parkinson’s Disease as the Rationale for Drug Treatment and Rehabilitation.
Diener, H., Timmann, D. and Jueptner, M. (1996). W52 Pathophysiology of cerebellar ataxia. Electroencephalography and Clinical Neurophysiology, 99(4), p.387.
Hi ,
I agree that Parkinson’s disease is one of the most common pathology that occurs due to damage on basal ganglia. This condition is characterized by gradual erosion of dopaminergic neurons. Since dopamine is an inhibitory neurotransmitter, its deficiency means that activities on thalamocortical pathway will be reduced, leading to exaggerated movements and tremors (Diener, Timmann &Jueptner, 1996; 387). Damage on cerebellum can lead to a condition known as cerebellum ataxia. When a lesion of the cerebellum is damaged, there will be abnormal balance and a person will be unable to maintain posture. This is because neural sensory output from the spinal cord and the sensory cortex cannot be integrated properly to fine-tune movements.
Re: Discussion 1
The cerebellum and basal ganglia have an essential role in the initiation and coordination of motor functions. They are both connected to the cerebral cortex through inputs and outputs (Bostan, Dum & Strick, 2010). The cerebellum has a critical role in imparting motor skills and in the correction of errors associated with commands of movement as per signals received from somatosensory, motor, and parietal association areas of the cortex and directing the corrected signals to motor areas (Caligiore et al., 2017; Senatore, 2011). The basal ganglia, on the other hand, has a role to play in the motor and premotor release of appropriate movements (Senatore, 2011). Both of these areas of the brain, if dysfunctional, can be associated with various medical conditions commonly characterised by movement disorders depending on the specific areas affected. Lesions in the substantia nigra, a component of the basal ganglia, have been commonly associated with Parkinson’s disease while that in the cerebella’s cerebro cerebellum can be associated with ataxia.
Parkinson’s disease is pathologically characterised by a degeneration in the dopaminergic neurons in the substantia nigra that are usually responsible for initiation of movements through release of the basal ganglia’s inhibitory effect on specific thalamic areas (Hauser, 2017; Senatore, 2011). The decreased ability to initiate movement manifests symptomatically as slowed movement or bradykinesia. In cerebellar ataxia with lesions affecting the cerebro cerebellum, there is incoordination of skilled movement initiation (Burn, 2013). In such patients, the person is unable to execute skilled movements such as finger-to-nose test. This movement incoordination is attributed to the inability of the cerebro cerebellum to correct cortical inputs before they are send back to the cortical motor and premotor areas (Burn, 2013).
Hi,
I totally agree with you that cerebellum and basal ganglia are brain parts that play a critical role in initiating and coordinating human motor functions. You have mentioned that dysfunctions in both areas of the brain are associated with various health conditions or complications. Cerebellar ataxia, for example, is a health condition that is associated with an inability of cerebro-cerebellum to execute skilled movements and correct cortical outputs. From my research, however, I have noted that the delay in movement initiation, which characterize cerebellum ataxia, emanate from a delay in the onset of cortex neural discharge due to reduced input from cerebellar hemispheres. Similarly, it should be noted that while unsteady movements may be as result of dysfunctions in different parts of the nervous system, abnormalities due to cerebellar ataxia are distinct by the tendency of persons to keep their lower limbs further apart, a clinical condition known as ‘broadened base’ (Widmaier, Raff & Strang, 2016).
Ahmad.
