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14. Projects from the epithalamus to the mid-
15. Is a major efferent pathway from the
Answers and Explanations
l-A. Rhinorrhea would most likely result from a fracture of the cribriform plate of the eth-
moid bone, which could tear the arachnoid membrane and result in a leakage of cerebrospinal
fluid (CSF) into the nasal cavity.
2-D. The hippocampal formation consists of the dentate gyrus, the hippocampus (cornu
ammonis), and the subiculum. The alveus, a fiber layer of the hippocampus, is the origin of the
3-E. Psychic blindness (visual agnosia), docility, hyperphagia, and hypersexuality are all
signs and symptoms of Kliiver-Bucy syndrome. Amnestic confabulation is the classic manifes-
tation of Korsakoff syndrome, a late stage of Wernicke's encephalopathy.
4-D. The primary olfactory cortex (prepiriform and periamygdaloid cortices) projects to the
thalamus (dorsomedial nucleus) and to the amygdaloid complex. The lateral olfactory stria pro-
jects to the primary olfactory cortex. The entorhinal cortex (also known as the second olfactory
cortex; area 28) receives input from the primary olfactory cortex.
5-E. The olfactory tract, a telencephalic structure, contains a relay nucleus, the anterior olfac-
tory nucleus, which projects fibers via the anterior commissure to the opposite olfactory bulb.
The olfactory tract projects via the lateral olfactory stria to the primary olfactory cortex.
6-E. Taste receptor cells are found in the tongue, epiglottis, palate, and esophagus. They are
special visceral afferent (SVA) receptors and are innervated by the facial nerve (CN VII), the
glossopharyngeal nerve (CN IX), and the vagal nerve (CN X). The chorda tympani contains
taste fibers from the anterior two-thirds of the tongue with cell bodies located in the geniculate
ganglion of CN VII of the petrous part of the temporal bone. Taste receptor cells are modified
epithelial cells; unlike olfactory receptor cells, which are first-order neurons, they do not pro-
ject to the central nervous system (CNS).
7-B. The peripheral taste pathway includes the geniculate ganglion of CN VII, the petrosal
ganglion of CN IX, the nodose ganglion of CN X, the solitary tract and nucleus, the central
tegmental tract, the ventral posteromedial nucleus of the thalamus, and the gustatory cortex,
which is located in the parietal operculum (area 43) and in the parainsular cortex. The semilu-
nar ganglion, the terminal ganglion of CN V, is not a structure of gustation.
8-D. The mamillary body projects via the mamillothalamic tract to the anterior nucleus of the
thalamus and via the mamillotegmental tract to the tegmental nuclei of the midbrain.
9-A. The olfactory (piriform) cortex is paleocortex; the hippocampal cortex is archicortex.
Archicortex and paleocortex are both three-layered cortices and are classified as allocortex
(heterogenic cortex). The cingulate gyrus is mesocortex, or juxtallocortex, a transitional cortex
between the neocortex and allocorte x.
10-D. This is a Foster Kennedy syndrome with ipsilateral anosmia, optic atrophy, and con-
tralateral papilledema. Papilledema in contradistinction to optic atrophy does not usually
result in visual field defects or loss of visual acuity.
11-B. The stria medullaris (thalami) contains septohabenular fibers (i.e., fibers that project
from the septal nuclei to the habenular nuclei). The stria medullaris (singular) should not be
confused with the striae medullares (plural). The striae medullares (rhombencephali) arise
from the arcuate nuclei of the medulla and are seen on the floor of the rhomboid fo ssa.
316 / Neuroanatomy