Midterms: Basal Ganglia (and thalamic nuclei)

Question 1

Definition: Hyperkinetic disorders involve excessive and abnormal movements, while hypokinetic disorders involve a lack or slowness of movement.

Answer 1

Types of Basal Nuclei Disorders

Question 2

Autosomal dominant inheritance, caused by a single gene defect on chromosome 4. Characterized by choreiform movements and progressive dementia.

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Huntington’s Disease

Question 2

Involuntary movement affecting one side of the body, typically caused by a small stroke affecting the subthalamic nucleus. Characterized by sudden, uncontrolled movements

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Hemiballismus

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Rapid, irregular, involuntary movements of limbs, face, and trunk, often associated with rheumatic fever. Triggered by streptococcal bacterial antigens.

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Sydenham Chorea (St. Vitus Dance)

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Progressive disease with tremor, rigidity, bradykinesia, and postural disturbances. Primarily involves neuronal degeneration in substantia nigra, affecting dopamine release in corpus striatum.

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Parkinson’s Disease

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Commonly caused by drugs blocking striatal dopamine receptors or depleting striatal dopamine. Symptoms typically disappear upon discontinuation of the causative agent.

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Drug-Induced Parkinsonism

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Characterized by slow, sinuous, writhing movements, typically affecting distal segments of limbs. Results from degeneration of the globus pallidus.

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Athetosis

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Characterized by sudden, repetitive, uncontrolled movements and vocalizations known as “tics.” Significant basal ganglia involvement observed, leading to dysfunction of GABAergic projections and relative increase in dopaminergic activity.

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Tourette Syndrome

Question 2

Situated lateral to the thalamus and divided by the internal capsule into the caudate nucleus and the lentiform nucleus. Crucial for motor and cognitive functions, with gray matter strands giving it a striated appearance.

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Corpus Striatum

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Located lateral to the thalamus, with divisions including head, body, and tail. Crucial for motor and cognitive functions, implicated in motor planning, decision making, and emotional processing.

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Caudate Nucleus

Question 3

Buried deep in cerebral hemisphere’s white matter, comprising the putamen and globus pallidus. Important for motor coordination and regulation, involved in movement disorders like Parkinson’s Disease.

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Lentiform Nucleus

Question 3

Situated in the temporal lobe near the uncus, considered a component of the limbic system. Affects the body’s response to environmental changes, influencing responses such as fear.

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: Amygdaloid Nucleus

Question 3

T or F
Substantia nigra neurons are dopaminergic and inhibitory, with many connections to corpus striatum. Subthalamic nuclei neurons are glutaminergic and excitatory, with many connections to globus pallidus and substantia nigra. Crucial for motor control and coordination.

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True

Question 3

Thin sheet of gray matter separated from the lateral surface of the lentiform nucleus by the external capsule. Adjacent to the subcortical white matter of the insula.

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Claustrum

Question 3

Assist in the regulation of voluntary movement and motor skill learning. Receives afferent inputs from various brain regions, integrates information within corpus striatum, and influences motor areas through circular pathways.

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Basal Nuclei Function

Question 3

T or F
Basal nuclei influence skilled sensory activities such as writing, drawing, and eye movements. Destruction can affect fine movements and result in paralysis of remaining movements on the opposite side of the body.

Answer 3

False
Basal nuclei influence skilled motor activities such as writing, drawing, and eye movements. Destruction can affect fine movements and result in paralysis of remaining movements on the opposite side of the body.

Question 3

Basal nuclei play a role in movement preparation, influencing axial and girdle movements of the body, as well as the positioning of proximal limb parts. Neuronal activity in certain globus pallidus neurons increases before active movements in distal limb muscles.

Answer 3

Preparatory Function of Basal Nuclei