Snell's Clinical Neuroanatomy

309

Review Questions

and 45 years. The involuntary movements are usually more rapid and jerky than those seen in patients with Sydenham chorea. Progressive mental changes lead to dementia and death. The γ -aminobutyric acid-secreting, substance P-secreting, and acetylcholine-secreting neurons of the stria tonigral pathway progressively degenerate. This results in the dopamine-secreting neurons of the substantia nigra becoming overactive; thus, the nigrostriatal pathway inhibits the caudate nucleus and the putamen. This causes the involuntary

movements. Atrophy of the caudate nucleus and putamen occurs.

3. T he clinical sign is known as hemiballismus. The sudden onset is usually caused by vascular impair ment due to hemorrhage or occlusion. Yes, hemibal lismus does involve the basal nuclei; it is the result of destruction of the contralateral subthalamic nucleus or its neuronal connections, causing the violent, uncoordinated movements of the axial and proximal limb muscles.

Review Questions

Directions: Each of the numbered items in this section is followed by answers. Select the ONE lettered answer that is CORRECT. 1. T he following statements concern the basal nuclei (ganglia): (a) The caudate nucleus and the red nucleus form the neostriatum (striatum). (b) The head of the caudate nucleus is connected to the putamen. (c) The tegmentum of the midbrain forms part of the basal nuclei. (d) The internal capsule lies lateral to the globus pallidus. (e) The basal nuclei are formed of white matter. 2. T he following statements concern the basal nuclei (ganglia): (a) The amygdaloid nucleus is connected to the caudate nucleus. (b) The lentiform nucleus is completely divided by the external capsule into the globus pallidus and the putamen. (c) The claustrum does not form part of the basal nuclei. (d) The corpus striatum lies medial to the thalamus. (e) The function of the claustrum is well known. 3. T he following statements concern the basal nuclei (ganglia): (a) The corpus striatum is made up of the caudate nucleus and the amygdaloid nucleus. (b) The head of the caudate nucleus lies lateral to the internal capsule. (c) The insula forms part of the basal nuclei. (d) The tail of the caudate nucleus lies in the roof of the lateral ventricle. (e) The subthalamic nuclei are functionally closely related to the basal nuclei and are considered to be part of them. 4. T he following statements concern the caudate nucleus: (a) It is divided into a head, neck, trunk, and tail. (b) It is an M-shaped mass of gray matter.

(c) Its body forms part of the roof of the body of the lateral ventricle. (d) Its head lies medial to the anterior horn of the lateral ventricle. (e) Its tail terminates anteriorly in the amygdaloid nucleus. 5. T he following statements concern the afferent corti costriate fibers to the corpus striatum: (a) Each part of the cerebral cortex is randomly pro jected to different parts of the corpus striatum. (b) Glutamate is not the neurotransmitter. (c) All parts of the cerebral cortex send fibers to the caudate nucleus and putamen. (d) The smallest input is from the sensory motor part of the cerebral cortex. (e) Most of the projections are from the cortex of the opposite side. 6. T he following statements concern the nigrostriatal fibers: (a) The neurons in the substantia nigra send axons to the putamen. (b) Acetylcholine is the neurotransmitter. (c) The nigrostriatal fibers are stimulatory in function. (d) The caudate nucleus does not receive axons from the substantia nigra. (e) Parkinson disease is caused by an increase in the release of dopamine within the corpus striatum. 7. T he following statements concern the efferent fibers of the corpus striatum: (a) Many of the efferent fibers descend directly to the motor nuclei of the cranial nerves. (b) Some of the striatopallidal fibers have γ -amino butyric acid as the neurotransmitter. (c) The striatonigral fibers pass from the red nucleus to the substantia nigra. (d) Many of the efferent fibers pass directly to the cerebellum. (e) The anterior horn cells of the spinal cord are influenced directly by the efferent fibers from the corpus striatum.

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