Snell's Clinical Neuroanatomy

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CHAPTER 9 Basal Nuclei (Basal Ganglia)

B

A

Figure 9-7 Axial (horizontal) positron emission tomography (PET) scans of a normal brain ( A ) and the brain of a patient with early Parkinson disease ( B ) following the injection of 18-f-fluorodopa. The normal brain image shows large amounts of the compound (yellow areas) distributed throughout the corpus striatum in both cerebral hemispheres. In the patient with Parkinson disease, the brain image shows that the total amount of the com pound is low, and it is unevenly distributed in the corpus striatum. (Courtesy Dr. Holley Dey.)

Premotor cortex and motor cortex

Putamen

Caudate nucleus

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Globus pallidus

Dopamine

GABA, substance P, acetylcholine

Figure 9-8 Diagram showing the degeneration of the inhibitory path way between the substantia nigra and the corpus striatum in Parkinson disease and the consequent reduc tion in the release of the neurotrans mitter dopamine in the striatum.

Substantia nigra