Snell's Clinical Neuroanatomy

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Answers and Explanations to Review Questions

nucleus does receive axons from the substantia nigra. E. Parkinson disease is caused by a reduc tion in the release of dopamine within the corpus striatum. 7. B is correct. Some of the striatopallidal fibers have γ -aminobutyric acid as the neurotransmitter. A. None of the efferent fibers from the corpus striatum descend directly to the motor nuclei of the cranial nerves. C. The striatonigral fibers pass from the cau date nucleus to the substantia nigra (see Fig. 9-3). D. No efferent fibers from the corpus striatum pass directly to the cerebellum. E. The anterior horn cells of the spinal cord are not influenced directly by the efferent fibers from the corpus striatum. 8. D is correct. The activities of the globus pallidus precede the activities of the motor cerebral cortex concerned with discrete movements of the hands and feet. A. The corpus striatum does not integrate

information received directly from the cerebellar cortex. B. The outflow of the basal nuclei is chan neled through the globus pallidus to the motor areas of the cerebral cortex, thus influencing mus cular activities. C. The globus pallidus influences the movements of the entire body. E. The activi ties of the basal nuclei are initiated by information received from the sensory cortex, the thalamus, and the brainstem. The answers for Figure 9-10, which shows a horizontal section of the cerebrum, are as follows: 9. F is correct. Structure 1 is the globus pallidus. 10. B is correct. Structure 2 is the internal capsule. 11. D is correct. Structure 3 is the putamen. 12. E is correct. Structure 4 is the external capsule. 13. C is correct. Structure 5 is the claustrum. 14. A is correct. Structure 6 is the anterior horn of the lateral ventricle.

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