Diencephalon and Limbic System

Question 1

1. Your patient has a tumor in the third ventricle, which is compressing the hypothala- mus. The patient exhibits signs associated with a decreased output of vasopressin by the posterior pituitary. What structure has the tumor compressed?
A. Supraoptic nucleus
B. Suprachiasmatic nucleus
C. Arcuate nucleus
D. Medial preoptic nucleus
E. Ventromedial nucleus

Answer 1

The answer is A. Vasopressin is produced and secreted by the supraoptic nucleus and the paraventricular nucleus.

Question 2

2. Your patient has been diagnosed with an eating disorder. The patient seems to have lost a significant amount of weight in the last year. A lesion in which of the following areas might have caused the patient’s problem?
   A. Medial preoptic nucleus
   B. Paraventricular nucleus
   C. Mammillary body
   D. Ventromedial nucleus of hypothalamus
   E. Lateral part of the anterior zone of hypothalamus

Answer 2

The answer is E. Lesions of the lateral hypothalamus produce severe aphagia.

Question 3

A magnetic resonance image of a female patient reveals that a calcified neural struc- ture is compressing structures adjacent to the superior colliculus. What complaint might you expect the patient to have?
A. Always being hot regardless of the environmental temperature
B. Insomnia
C. Amnesia
D. Hearing voices telling wildly untrue stories
E. Difficulty remembering where she put the car keys each morning

Answer 3

The answer is B. The patient has a calcified pineal gland, which may reduce the out-
put of melatonin, a sleep-inducing hormone.

Question 4

4. On New Year’s Eve, an elderly male staggers into the emergency room smelling of al- cohol, unshaven, and having no wallet or identification. The patient gave his name but did not remember his address or any other personal information. The patient said he was on a business trip to the city but could not recall where he was staying. When questioned 5 minutes later, he could not remember why he was in the city, claimed he was an off-duty airline pilot, and identified one of the nurses as a flight at- tendant. A neurological exam revealed a gaze-evoked nystagmus in all directions. His muscle strength was 5/5, but he walked with a broad-based gait. Together, these signs and symptoms suggest that the patient may have:
A. Alzheimer’s disease
B. Subacute combined degeneration
C. Huntington’s disease
D. Korsakoff’s syndrome 
E. Neurosyphilis

Answer 4

The answer is D. Korsakoff’s syndrome is usually preceded by Wernicke’s encepha- lopathy, which includes mental changes, abnormal eye movements, and gait ataxia. Patients with Korsakoff’s syndrome have anterograde short-term memory loss, which may be combined with confabulations, in which they make up stories about events that never occurred.

Question 5

5. On New Year’s Eve, an elderly male staggers into the emergency room smelling of al- cohol, unshaven, and having no wallet or identification. The patient gave his name but did not remember his address or any other personal information. The patient said he was on a business trip to the city but could not recall where he was staying. When questioned 5 minutes later, he could not remember why he was in the city, claimed he was an off-duty airline pilot, and identified one of the nurses as a flight at- tendant. A neurological exam revealed a gaze-evoked nystagmus in all directions. His muscle strength was 5/5, but he walked with a broad-based gait. What might be one site of neuronal degeneration in the patient in the previous de- scription?
A. Head of the caudate nucleus
B. Substantia nigra, pars compacta
C. Mammillary bodies
D. Ventrobasal complex
E. Basal nucleus of Meynert

Answer 5

The answer is C. In these patients, there are neuronal changes in the anterior vermis of the cerebellum, in gaze centers or ocular neurons in the midbrain and pons, and in the mammillary bodies and dorsomedial nucleus of the thalamus.