Question

Which nucleus is involved in hemiballismus?

• A. Globus pallidus
• B. Caudate nucleus
• C. Substantia nigra
• D. Subthalamic

Hint:

Hemiballismus can often be seen after a stroke affecting the subthalamic nucleus, leading to one-sided, uncontrolled movements.

Answer 1

The Correct Option is D

To solve this question, we need to identify the nucleus involved in the condition known as hemiballismus.

Hemiballismus is a rare movement disorder characterized by involuntary, violent, and wide-amplitude movements, primarily affecting one side of the body. This condition is caused by lesions in a specific part of the brain called the subthalamic nucleus.

Let's evaluate the given options one by one:

• Globus pallidus: This is part of the basal ganglia and plays a role in regulation of voluntary movement, but it is not the primary nucleus involved in hemiballismus.
• Caudate nucleus: Also part of the basal ganglia, the caudate nucleus is associated with various motor processes and learning, but it is not related to hemiballismus.
• Substantia nigra: This structure is involved in dopamine production and regulation of movement, often associated with Parkinson's disease, but not with hemiballismus.
• Subthalamic nucleus: This nucleus is crucial in regulating movement and is directly involved in hemiballismus. Lesions here lead to the characteristic movements observed in this condition.

The involvement of the subthalamic nucleus in hemiballismus is well-documented, as it integrates signals in the motor pathways that control movements. A lesion or dysfunction here disrupts the balance of these pathways, resulting in the distinctive involuntary movements.

Thus, the correct answer is: Subthalamic.