neuroanatomy 3rd Comprehensive Examination 1 - 50 Flashcards Preview

neuroanatomy > neuroanatomy 3rd Comprehensive Examination 1 - 50 > Flashcards

Flashcards in neuroanatomy 3rd Comprehensive Examination 1 - 50 Deck (50):

1. The cuneus is separated from the lingual gyrus by the
(A) rhinal sulcus
(B) calcarine sulcus
(C) parietooccipital sulcus
(D) collateral sulcus
(E) intraparietal sulcus

l-B. The calcarine sulcus separates the cuneus from the lingual gyrus. The banks of the calcarine sulcus contain the visual cortex.


2. Which sinus receives drainage from the greatest number of arachnoid granulations?
(A) Straight sinus
(B) Transverse sinus
(C) Sigmoid sinus
(D) Superior sagittal sinus
(E) Cavernous sinus

2-D. The superior sagittal sinus receives drainage from the greatest number of arachnoid granulations.


3. Which of the following statements concerning the Rathke pouch is true?
(A) It is a mesodermal diverticulum
(B) It is derived from the neural tube
(C) It gives rise to the adenohypophysis
(D) It gives rise to the epiphysis
(E) It gives rise to the neurohypophysis

3-C. The Rathke pouch is an ectodermal outpocketing of the stomodeum anterior to the buccopharyngeal membrane and gives rise to the adenohypophysis (pars distalis, pars tuberalis, and
pars intermedia).


4. Which of the following statements concerning the lateral horn of the spinal cord is true?
(A) It contains preganglionic parasympathetic neurons
(B) It gives rise to a spinocerebellar tract
(C) It is present at all spinal cord levels
(D) It gives rise to preganglionic sympathetic fibers
(E) It is most prominent at sacral levels

4-D. The lateral horn (T1-L3) gives rise to preganglionic sympathetic fibers.


5. Which of the following statements concerning the nucleus dorsalis of Clarke is true?
(A) It is found in the ventral horn
(B) It projects to the cerebellum
(C) It is present at all spinal levels
(D) It is most prominent at upper cervical levels
(E) It is homologous to the cuneate nucleus of the medulla

5-B. The nucleus dorsalis of Clarke (C8-L3) gives rise to the dorsal spinocerebellar tract, which ascends and enters the cerebellum through the inferior cerebellar peduncle.


6. Which of the following groups of cranial nerves is closely related to the corticospinal
(A) CN III, CN IV, and CN V
(B) CN III, CN V, and CN VII
(E) CN III, CN IX, and CN X

6-D. In the midbrain, the pyramidal tract lies in the basis pedunculi; oculomotor fibers of CN
III pass through the medial part of the basis pedunculi. In the pons, the pyramidal tract lies in the base of the pons; abducent fibers of CN VI pass through the lateral part of the pyramidal fasciculi. In the medulla, the pyramidal tracts form the medullary pyramids; hypoglossal fibers of
CN XII lie just lateral to the pyramids.


7. The primary auditory cortex is located in the
(A) frontal operculum
(B) postcentral gyrus
(C) superior parietal lobule
(D) inferior parietal lobule
(E) transverse temporal gyri

7-E. The primary auditory cortex (i.e., areas 41 and 42) is located in the transverse temporal
gyri of Heschl, a part of the superior temporal gyrus.


8. The neocerebellum projects to the motor cortex via the
(A) anterior thalamic nucleus
(B) ventral anterior nucleus
(C) ventral lateral nucleus
(D) lateral dorsal nucleus
(E) lateral posterior nucleus

8-C. The neocerebellum (the posterior lobe minus the vermis and the paravermis) sends input to the motor cortex through the ventral lateral nucleus of the thalamus. The pathway is the neocerebellar cortex, dentate nucleus, contralateral ventral lateral nucleus of the thalamus, and motor cortex (area 4).


9. The dentatothalamic tract decussates in the
(A) diencephalon
(B) rostral midbrain
(C) caudal midbrain
(D) rostral pons
(E) caudal pons

9-C. The dentatothalamic tract decussates in the caudal midbrain tegmentum at the level of the
inferior colliculus. This massive decussation of the superior cerebellar peduncles is characteris-
tic of this level.


10. A pituitary tumor is most frequently associated with a(an)
(A) homonymous hemianopia
(B) homonymous quadrantanopia
(C) bitemporal hemianopia
(D) binasal hemianopia
(E) altitudinal hemianopia

10-C. Pituitary tumors frequently compress the decussating fibers of the optic chiasm and pro-
duce a bitemporal hemianopia. Nasal fibers decussate, and temporal fibers remain ipsilateral.


11. Resection of the anterior portion of the left temporal lobe is most frequently associated
with a
(A) left homonymous hemianopia
(B) right upper homonymous quadrantanopia
(C) right lower homonymous quadrantanopia
(D) left upper homonymous quadrantanopia
(E) left lower homonymous quadrantanopia

11-B. Resection of the anterior portion of the temporal lobe transects the fibers of the loop of Meyer and results in a contralateral upper homonymous quadrantanopia. Inferior retinal quadrants are represented in the inferior banks of the calcarine sulcus.


12. A 65-year-old farmer has experienced dull frontal headaches for the last 3 weeks. Neurologic examination reveals spastic hemiparesis on the right side and a pronator drift on the
right side. What is the most likely diagnosis?
(A) Brain tumor
(B) Myasthenia gravis
(C) Progressive supranuclear palsy
(D) Pseudotumor cerebri
(E) Subacute combined degeneration

12-A. Headache and papilledema are signs of brain tumor, and pronator drift is a frontal lobe sign due to weakness of the supinator muscle. Tumor pressure on the corticospinal tract results
in contralateral spastic hemiparesis. In progressive supranuclear palsy the patient cannot look down, in myasthenia gravis there is weakness of skeletal muscle, in pseudotumor cerebri there
are no mass lesions but headache and papilledema, and in subacute combined degeneration the posterior columns and the corticospinal tracts are affected.


13. An 18-year-old high school student has fractured a cervical vertebra in an automobile accident. Neurologic examination reveals hemiparesis on the right side, Babinski and
Hoffmann signs on the right side, loss of pain and temperature sensation on the left side, and normal pallesthesia in all extremities. The spinal cord lesion that would most likely explain the deficits involves the
(A) dorsal column, left side
(B) dorsal column, right side
(C) lateral column, left side
(D) lateral column, right side
(E) anterior column, bilateral

13-D. The lateral corticospinal tract and the lateral spinothalamic tract are both found in the lateral column. Transection of the corticospinal tract results in an ipsilateral paresis, and transection of the spinothalamic tract results in a contralateral loss of pain and temperature sensation. Pallesthesia (vibration sense) is normal.


14. Light shone into the left eye elicits a direct pupillary reflex but no consensual reflex. A lesion in which of the following structures ac-counts for this deficit?
(A) Optic nerve, left eye
(B) Optic nerve, right eye
(C) Optic tract, right side
(D) Oculomotor nerve, right side
(E) Oculomotor nerve, left side

14-D. The contralateral oculomotor nerve is responsible for the consensual reaction.


15. A 53-year-old housewife has a normal
corneal blink reflex on her left side but no consensual blink on her right side. Which of the following neurologic deficits or signs would you expect to find on the right side?
(A) Hyperacusis
(B) Hemianhidrosis
(C) Hemianesthesia
(D) Internal ophthalmoplegia
(E) Severe ptosis

15-A. Hyperacusis is an increased acuity of hearing and undue sensitivity to low tones. It results from paralysis of the stapedius muscle (CN VII); the stapedius reduces the amplitude of sound vibrations of the stapes in the oval window.


16. A 49-year-old man has a loss of tactile sensation involving the anterior two-thirds of his tongue on the left side. Neurologic examination reveals paralysis of the masseter muscle on the left side and loss of pain and temperature sensation from the teeth of the mandible on the left side. He has a lesion involving which one of the following nerves?
(A) Chorda tympani nerve
(B) Facial nerve
(C) Hypoglossal nerve
(D) Trigeminal nerve, mandibular division
(E) Trigeminal nerve, ophthalmic division

16-D. The mandibular division of the trigeminal nerve (CN V-3) innervates the muscles of mastication (e.g., masseter muscle) and mediates the tactile sensation of the anterior two-thirds of the tongue. The glossopharyngeal nerve (CN IX) provides the tactile, nociceptive, and taste innervation of the posterior one-third of the tongue. The facial nerve (CN VII) provides taste innervation to the anterior two-thirds of the tongue.


17. A 62-year-old lawyer suffers a stroke and falls while cutting his lawn. He does not lose consciousness. Neurologic examination reveals loss of pain sensation on the right side of the face and on the left side of the body, falling and past pointing to the right side, difficulty swallowing, horizontal nystagmus to the right side, deviation of the uvula to the left when asked to say "ah," and Horner syndrome on the right side. The most likely site of this man's lesion is the
(A) Internal capsule, left side
(B) Midbrain, right side
(C) Pontine tegmentum
(D) Lateral medulla, right side
(E) Medial medulla, right side

17-D. This is the classic lateral medullary syndrome, which is also known as Wallenberg syndrome (see Figure 14-IB).


18. A 64-year-old pharmacology professor
complains of weakness in his right leg and double vision, especially when moving his eyes to the left. Neurologic examination reveals a dilated pupil and ptosis on the left side and a Babinski sign (extensor plantar reflex) on the right side. The most likely site of this patient's lesion is the
(A) Midbrain crus cerebri, right side
(B) Midbrain crus cerebri, left side
(C) Pontine base, left side
(D) Pontine tegmentum, right side
(E) Internal capsule, right side

18-B. This is a classic medial midbrain lesion characteristic of Weber syndrome. It includes the crus cerebri and the exiting intra-axial fibers of the oculomotor nerve (see Figure 14-3C).


19. While working in his shop, a 21-year-old machinist is struck by a penetrating metal fragment in the side of the head. Neurologic examination reveals the following language deficits: fluent speech, no ability to read aloud, no ability to repeat what you say, no ability to compensate by writing. The patient understands the problem but cannot resolve it.
Where would you expect to find the fragment?
(A) Between the supramarginal gyrus and
the inferior frontal gyrus
(B) In the angular gyrus
(C) In the transverse gyri
(D) In the posterior one-third of the superior temporal gyrus
(E) In the paracentral gyrus

19-A. The metal fragment is found between the inferior frontal gyrus and the supramarginal gyrus. The two gyri are connected by the arcuate fasciculus; transection results in conduction
aphasia. The arcuate fasciculus interconnects Broca area from Wernicke area. The key deficit is the inability to repeat (see Figure 24-1).


20. The catecholamine norepinephrine is the primary neurotransmitter found in the
(A) adrenal cortex
(B) adrenal medulla
(C) postganglionic parasympathetic neurons to the circular smooth muscle layer of the jejunum
(D) postganglionic sympathetic neurons to the smooth muscle of the renal arterioles
(E) postganglionic sympathetic neurons to the sweat glands

20-D. Norepinephrine is the neurotransmitter of postganglionic sympathetic neurons, with the
exception of sweat glands and some blood vessels that receive cholinergic sympathetic innervation. Epinephrine is produced by the chromaffin cells of the adrenal medulla.


21. A 30-year-old man sustains brain damage as the result of an automobile accident. Neurologic examination reveals incomplete retrograde amnesia and severe anterograde amnesia as well as inappropriate social behavior,
including hyperphagia, hypersexuality, and
general disinhibition. The brain injury would
most likely involve the
(A) frontal lobes, lateral convexity
(B) frontal lobes, medial surface
(C) temporal lobes, lateral convexity
(D) temporal lobes, medial surface
(E) thalami

21-D. Bilateral damage of the medial temporal gyri, including the amygdalae, may cause severe memory loss (hippocampal formations). Such damage to the amygdalae may lead to inappropriate social behavior (e.g., hyperphagia, hypersexuality, general disinhibition). Bilateral destruction of the amygdalae results in the Kliiver-Busy syndrome.


22. A 55-year-old woman has difficulty reading small print. She most likely has
(A) astigmatism
(B) cataracts
(C) optic atrophy
(D) macular degeneration
(E) presbyopia

22-E. Presbyopia is a progressive loss of the ability to accommodate, the decreased ability to focus on near objects. Astigmatism is the difference in refracting power of the cornea and lens in different meridians. Cataracts are opacities of the lens that appear with aging. Optic atrophy is degeneration of the optic nerve and papillomacular bundle and loss of central vision.


23. The principal postnatal change in the
pyramids is due to
(A) an increase of corticospinal neurons from the paracentral lobule
(B) an increase in the total number of corticospinal axons
(C) a large increase of Schwann cells found in the motor cortex
(D) an increase in endoneural tubes to guide sprouting axons
(E) myelination of preexisting corticospinal axons

23-E. The corticospinal fibers are not completely myelinated at birth; this does not occur until between 18 months and 2 years of age. During this time, the Babinski reflex is elicitable; later it is suppressed.


24. Special visceral afferent (SVA) neurons that innervate receptor cells in taste buds
synapse in the
(A) geniculate ganglion
(B) inferior salivatory nucleus
(C) nucleus of the solitary tract
(D) spinal trigeminal nucleus
(E) ventral posteromedial (VPM) nucleus

24-C. The nucleus of the solitary tract receives taste fibers from cranial nerves VII, IX, and X.
Neurons of this tract project to the ventral posteromedial (VPM) nucleus of the thalamus.


25. A woman receives an injection of a ra-
dioisotope to determine regional blood flow in the brain. She has a positron emission tomography (PET) scan to visualize variations in cortical blood flow. The examiner asks her to think about flexing her index finger without actually doing it. In which of the following cortical areas would you expect to see increased blood flow?
(A) Broca area
(B) Angular gyrus
(C) Motor strip
(D) Supplementary motor cortex
(E) S-I somatosensory cortex

25-D. The supplementary motor cortex (M-2) plans for motor activity. Broca area is a language center, the angular gyrus is concerned with mnemonic constellations, the motor strip (M-l) gives rise to the corticospinal and corticobulbar tracts, and the S-l somatosensory cortex subserves somatic sensibility.


26. Destruction of the right cuneate nucleus results in which of the following sensory deficits?
(A) Apallesthesia, left hand
(B) Apallesthesia, right hand
(C) Apallesthesia, left foot
(D) Analgesia, left hand
(E) Analgesia, right foot

26-B. Destruction of the right cuneate nucleus results in apallesthesia (loss of vibration sensation) in the right hand. The cuneate nucleus, a way station in the posterior column—medial lem-
niscus pathway, mediates tactile discrimination and vibration sensation.


27. The elaboration of acetylcholine (ACh) results in which of the following postganglionic sympathetic responses?
(A) Constriction of cutaneous blood vessels
(B) Contraction of arrector pili muscles
(C) Decreased gastrointestinal motility
(D) Increased ventricular contractility
(E) Stimulation of eccrine sweat glands

27-E. Eccrine sweat glands are innervated by postganglionic sympathetic cholinergic fibers. Apocrine sweat glands are innervated by postganglionic sympathetic norepinephrinergic fibers.
(Note: This item is often tested.)


28. Nausea is mediated by which of the following neural structures?
(A) Celiac ganglion
(B) Greater splanchnic nerve
(C) Superior mesenteric ganglion
(D) Inferior mesenteric ganglion
(E) Vagal nerves

28-E. The vagal nerves mediate the feeling of nausea via general visceral afferent (GVA) fibers.


29. Cerebrospinal fluid (CSF) enters the
bloodstream via the
(A) arachnoid villi
(B) choroid plexus
(C) interventricular foramen of Monro
(D) lateral foramina of Luschka
(E) median foramen of Magendie

29-A. Cerebrospinal fluid (CSF) enters the bloodstream via the arachnoid villi. Hypertrophied arachnoid villi are called arachnoid granulations or pacchionian bodies.


30. A computed tomography (CT) scan of the head of a newborn infant reveals enlargement of the lateral ventricles and the third ventricle. The cause of this hydrocephalus is most likely which of the following?
(A) Aqueductal stenosis
(B) Adhesive arachnoiditis
(C) Choroid plexus papilloma
(D) Calcification of the arachnoid granulations
(E) Stenosis of the median foramen

30-A. Aqueductal stenosis results in enlargement of the third and lateral ventricles. The condition is strongly associated with prenatal infections (e.g., cytomegalovirus infection). Congenital hydrocephalus occurs in 1:1000 live births. Mental retardation, spasticity, and tremor are common. Shunting is the treatment of choice; cerebrospinal fluid (CSF) is shunted from the distended ventricle to the peritoneal cavity.


31. The cellular neuropathology of Alzheimer disease resembles most closely that seen in
(A) Huntington disease
(B) multi-infarct dementia
(C) Pick disease
(D) neurosyphilis
(E) trisomy 21

31-E. Alzheimer disease is commonly seen in trisomy 21, or Down syndrome, after 40 years of age. It is the most common single cause of mental retardation. The neuropathology of Down syndrome is similar to that of Alzheimer disease: reduced choline acetyltransferase activity, cell loss in the nucleus basalis of Meynert, an increase of amyloid ^-protein, and Alzheimer neurofibrillary changes and neuritic plaques are always found.


32. A 40-year-old carpenter visits his general practitioner. He complains of shortness of breath and difficulty in performing his construction work. During the history-taking, he tells his physician that he had an attack of gastroenteritis 3 weeks ago. The neurologic examination reveals ascending weakness and tingling in the legs and absence of muscle stretch reflexes in the legs. Cerebrospinal fluid (CSF) analysis shows elevated protein without significant pleocytosis. The most likely diagnosis is
(A) amyotrophic lateral sclerosis (ALS)
(B) Guillain-Barre syndrome
(C) multiple sclerosis
(D) myasthenia gravis
(E) Werdnig-Hoffmann syndrome

32-B. This represents classic Guillain-Barre syndrome, with prior infection, ascending paralysis, distal paresthesias, and albuminocytologic dissociation.


33. A 25-year-old female high school teacher has had difficulty walking. Five years ago she experienced a loss of vision in her left eye that improved in 3 weeks. Neurologic examination reveals a right afferent pupillary defect, hyperreflexia in both legs, reduced proprioception in both feet, and extensor plantar reflexes. Cerebrospinal fluid (CSF) analysis shows oligoclonal bands. The most likely diagnosis is
(A) amyotrophic lateral sclerosis (ALS)
(B) Guillain-Barre syndrome
(C) multiple sclerosis
(D) syringobulbia
(E) subacute combined degeneration

33-C. This is a classic description of multiple sclerosis. Characteristics of the condition are exacerbations and remissions, involvement (demyelination) of long tracts, blurred vision, and an afferent pupillary defect. Cerebrospinal fluid (CSF) contains electrophoretically detectable oligoclonal immunoglobulin (oligoclonal bands). In addition, rates of synthesis and concentration of intrathecally generated immunoglobulin G and immunoglobulin M in the CSF are elevated. Oligoclonal bands are also found in syphilis, meningoencephalitis, subacute sclerosing panencephalitis (SSPE), and the Guillain-Barre syndrome.


34. A 48-year-old woman complains of a progressive loss of hearing and a buzzing noise in her right ear. Neurologic examination reveals an absent corneal reflex on the right side and sagging of the right corner of the mouth. Magnetic resonance imaging (MRI) shows a mass in the right cerebellopontine angle. The neoplasm would most likely arise from proliferation of which of the following cell types?
(A) Fibrous astrocytes
(B) Protoplasmic astrocytes
(C) Microglia
(D) Schwann cells
(E) Oligodendrocytes

34-D. Proliferating Schwann cells may give rise to schwannomas, which are also called acoustic neuromas or neurilemmomas.


35. A 50-year-old plumber complains of weakness in his left leg and a loss of pain and temperature in his right leg. Neurologic examination reveals exaggerated muscle stretch reflexes (MSRs) in the left leg and an extensor plantar reflex on the left side. The lesion would most likely be located in the
(A) crus cerebri
(B) internal capsule
(C) lateral medulla
(D) medial medulla
(E) spinal cord

35-E. A hemisection of the spinal cord would result in an ipsilateral spastic paresis below the lesion and a loss of pain and temperature on the contralateral side. The plantar response would be extensor and ipsilateral (Babinski sign).


36. A 20-year-old comatose man has sustained massive head injuries in a automobile accident. Ice water injected into the external auditory meatus elicits no ocular response. Head rotation does not result in the doll's head eye phenomenon. The lesion causing the injuries most likely affects the
(A) cochlear nuclei
(B) dentate nuclei
(C) ossicles
(D) utricles
(E) vestibular nuclei

36-E. A lesion of the vestibular nuclei (lower brainstem) eliminates oculovestibular reflexes.


37. Which of the following agents may be used as an alternative to L-dopa to alleviate the chemical imbalance found in the striatum of a patient with Parkinson disease?
(A) Aspartate
(B) An anticholinergic agent
(C) Glutamate
(D) A dopamine antagonist
(E) A serotonin reuptake inhibitor

37-B. An anticholinergic agent (e.g., trihexyphenidyl) may be used as an alternative to L-dopa to alleviate the chemical imbalance found in the striatum of a patient with Parkinson disease.


38. Which of the following antidepressants is the most selective inhibitor of serotonin reuptake?
(A) Amitriptyline
(B) Doxepin
(C) Fluoxetine
(D) Nortriptyline
(E) Tranylcypromine

38-C. Fluoxetine (Prozac) is the most selective inhibitor of serotonin reuptake.


39. A 20-year-old woman suddenly experi-
ences double vision. Neurologic examination reveals diplopia when she attempts to look to the left, inability to adduct the right eye, nystagmus in the left eye on attempted lateral conjugate gaze to the left, and convergence of both eyes on a near point. These deficits would result from occlusion of a branch of which of
the following arteries?
(A) Anterior cerebral
(B) Basilar
(C) Middle cerebral
(D) Posterior cerebral
(E) Ophthalmic

39-B. The paramedian (transverse pontine) branches of the basilar artery supply the medial longitudinal fasciculus (MLF) of the pons. Destruction of this fasciculus results in MLF syndrome [internuclear ophthalmoplegia (INO)]. In addition, the superior cerebellar artery may irrigate the MLF.


40. The various glial cell types of the central nervous system (CNS) play a role in all of the following functions EXCEPT
(A) production of myelin
(B) production of intermediate filaments
(C) serve as pluripotent stem cells that differentiate into new neurons in response to injury
(D) metabolism of neurotransmitters
(E) transporting K+ from areas of high concentration to areas of lower concentration

40-C. Glial cells cannot transform into neurons; however, they can reproduce, become larger, and produce glial filaments. Hypertrophied astrocytes with their fibrils are the scar tissue of the central nervous system (CNS).


41. A glioma located under the facial colliculus could result in paralysis o all of the following muscles EXCEPT
(A) Buccinator
(B) Lateral rectus
(C) Lateral pterygoid
(D) Posterior belly of digastric
(E) Orbicularis oculi

41-C. The internal genu of the facial nerve (CN VII) and the abducent nucleus (CN VI) underlie the facial colliculus. The lateral pterygoid muscle is innervated by the motor division of the trigeminal nerve (CN V).


42. A 40-year-old plumber has periodic
episodes of spontaneous jerks on the right side of his face. These movements may spread to the hand and then to the leg. The locus of this motor march is in the
(A) left frontal lobe
(B) right frontal lobe
(C) left parietal lobe
(D) right parietal lobe
(E) left temporal lobe

42-A. This a case of Jacksonian epilepsy, a Jacksonian march. The muscle jerks progress from a body focus to an adjacent body part: face —■» hand —> arm —> leg. The focal attack follows the homunculus of the precentral gyrus and the anterior gyrus of the paracentral lobule.


43. Tritiated proline is injected into the left
upper quadrant of the left retina for antero-
grade transport. Radioactive label would be
found in the
(A) cuneus, left side
(B) cuneus, right side
(C) lingual gyrus, left side
(D) lingual gyrus, right side
(E) optic nerve, left side

43-A. A lesion of the upper left retinal quadrant in the left eye would show radioactive label in the left cuneus. Lesions of the cuneus result in lower field defects, and lesions of the lingual gyrus result in upper field defects. Remember, upper retinal quadrants project to the upper banks of the calcarine fissure, and lower retinal quadrants project to the lower banks of the calcarine fissure.


44. Tritiated leucine [(3H)-leucine] is injected into the left inferior olivary nucleus (ION) for anterograde transport. Radioactive label would be found in the
(A) lateral cuneate nucleus, left side
(B) nuclei of the lateral lemnisci
(C) dentate nucleus, right side
(D) nucleus dorsalis of Clarke
(E) superior olivary nucleus, left side

44-C. The dentate nucleus receives massive input from the contralateral ION; it projects crossed fibers to the ventral lateral nucleus of the thalamus and red nucleus (parvocellular part). The lateral cuneate nucleus gives rise to the cuneocerebellar tract; and the lateral lemniscus and its nuclei are important way stations in the auditory pathway.


45. Tritiated proline [(3H)-proline] is injected into the right ventral posterolateral nucleus for retrograde transport. Radioactive label would be found in the
(A) nucleus ruber, right side
(B) nucleus gracilis, left side
(C) nucleus gracilis, right side
(D) lateral cuneate nucleus, left side
(E) ventral lateral nucleus

45-B. The right ventral posterolateral nucleus receives posterior column modalities via the medial lemniscus from the left side of the body. The nucleus ruber is a midbrain motor nucleus: it plays a roll in the control of flexor tone. The lateral cuneate nucleus projects unconscious proprioception to the cerebellum, (e.g., from muscles and tendons). The ventral lateral nucleus receives input from the cerebellum (dentate nucleus).


46. Horseradish peroxidase is injected into the nucleus of the inferior colliculus for retrograde transport. Label would be found in which of the following nuclei?
(A) medial geniculate nucleus
(B) lateral geniculate nucleus
(C) superior olivary nucleus
(D) inferior olivary nucleus
(E) transverse gyrus of Heschl

46-C. The nucleus of the inferior colliculus projects retrogradely to the inferior olivary nucleus of the caudal pons. The medial geniculate nucleus is an auditory way station, the inferior olivary nucleus is a cerebellar relay station, and the transverse gyrus of Heschl is a primary auditory center. Retrograde transport studies show that horseradish peroxidase is picked up by the axon terminals and transported to the perikarya; anterograde studies show that labeled amino acids are taken up by the perikarya and transported anterograde to distant nuclei.


47. Each of the following statements concerning the temporal lobe is true EXCEPT
(A) it contains the primary somatosensory cortex
(B) it contains the primary auditory cortex
(C) it contains the Wernicke speech area
(D) it is separated from the frontal lobe by the lateral sulcus
(E) it contains an auditory association cortex

47-A. The primary somatosensory cortex (areas 3, 1, and 2) is located in the postcentral gyrus (sensory strip) of the parietal lobe.


48. Each of the following statements concerning cerebral ventricles is true EXCEPT
(A) all ventricles contain choroid plexus
(B) the frontal and occipital horns of the lateral ventricles lack choroid plexus
(C) the body of the lateral ventricle contains the calcified glomus of the choroid plexus
(D) the third and fourth ventricles are inter-
connected by the cerebral aqueduct
(E) the fourth ventricle contains the foramina of Luschka and Magendie

48-C. The trigone of the lateral ventricles contains the calcified glomera of the choroid plexus. These calcifications are visible in radiographic and computed tomographic (CT) images.


49. Each of the following circumventricular
organs is highly vascularized with fenestrated capillaries EXCEPT
(A) the area postrema
(B) the pineal body
(C) the subcommissural organ
(D) the subfornical organ
(E) the median eminence of the tuber cinereum

49-C. The subcommissural organ lies in the roof of the cerebral aqueduct near the posterior commissure. All circumventricular organs except the subcommissural organ have fenestrated capillaries, and, thus, lack a blood-brain barrier.


50. The middle cerebral artery irrigates each of the following structures or areas EXCEPT
(A) the paracentral lobule
(B) the inferior parietal lobule
(C) Broca speech area
(D) Wernicke speech area
(E) the primary auditory cortex

50-A. The anterior cerebral artery irrigates the paracentral lobule, which lies on the medial surface of the hemisphere.