Repeated MRI scans of patients with Huntington’s Chorea demonstrate progressive atrophy within which of the following structures?
A caudate
B globus pallidus
C substantia nigra
D subthalamic nucleus
The correct answer and explanation is:
The correct answer is A. caudate.
Explanation:
Huntington’s Chorea is a neurodegenerative disorder that leads to the progressive degeneration of specific areas of the brain. One of the primary structures affected is the caudate nucleus, which is part of the basal ganglia. The basal ganglia are involved in the regulation of movement, and damage to these structures leads to the characteristic motor symptoms seen in Huntington’s disease, such as chorea (involuntary jerky movements) and dystonia (muscle contractions that cause twisting and abnormal postures).
MRI scans of patients with Huntington’s disease show progressive atrophy (shrinkage) of the caudate nucleus over time. As the disease progresses, the atrophy extends to the putamen, another component of the basal ganglia, which results in further motor dysfunction.
The basal ganglia play a crucial role in controlling movement and coordination. In Huntington’s disease, a genetic mutation causes the production of an abnormal protein (huntingtin), which leads to the death of neurons in the caudate and other areas of the basal ganglia. The loss of these neurons interferes with the normal functioning of the basal ganglia, contributing to the motor abnormalities seen in patients with Huntington’s disease.
Although other structures like the globus pallidus (B), substantia nigra (C), and subthalamic nucleus (D) are also involved in movement regulation, they are not primarily responsible for the progressive atrophy observed in Huntington’s disease. The substantia nigra, for example, is more prominently affected in Parkinson’s disease, while the subthalamic nucleus plays a role in the regulation of motor function but does not undergo significant atrophy in Huntington’s disease. Therefore, the caudate nucleus is the most affected structure in this condition.