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An 82-year-old man in a nursing home, who has become increasingly confused over the past several years, now presents with a respiratory illness accompanied by agitation and disorientation. A head MRI is obtained. The man later dies of his illness, and an autopsy is performed. Histologic examination of the cerebral structures indicated by the arrows reveals accumulation of senile plaques and neurofibrillary tangles. Which of the following are these structures?
A. Auditory temporal cortex
B. Cingulate cortex
C. Hippocampus
D. Mammillary bodies
E. Thalamus
F. Visual occipital cortex
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senile plaques and neurofibrillary tangles--this is typical Alzheimer's, right? I choose B. cingulate cortex. I remebered that Alzheimer's spares primary motor and sensory area in the cortex.
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but no clinical clue other than those investigation about alziemer's dz so how can predict so ?
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correct ans is C.hippocampus.
The dementing condition referred to above is Alzheimer disease, which results in memory impairment mostly affecting short-term memory functions. The pathogenesis is related to accumulation of beta-amyloid in senile plaques and intraneuronal deposits of abnormal tau protein within neurons (neurofibrillary tangles). The hippocampus is one of the earliest and most severely affected cerebral regions. This phylogenetically old region of the brain is known to play an important role in short-term memory. It lies deep in the hippocampal fissure, medial to the temporal lobe.
Through the fimbria, it projects its most important efferent pathway to the mammillary bodies (choice D), which would be seen in a more rostral (anterior) view as a pair of rounded structures on the ventral surface of the brain.
The mammillary bodies, in turn, project to the thalamus (choice E), which are seen in this picture as large gray masses lying adjacent to the third ventricle and partially fused along the midline.
The anterior nucleus of the thalamus is the source of the projection to the cingulate cortex (choice B), which is the gyrus just above the corpus callosum, on the medial surface of the frontal lobes. The cingulate cortex gives rise to axons that connect to the entorhinal cortex (in the temporal lobe) and back to the hippocampus. This circle of projections constitutes the circuit of Papez, the structures of which are considered essential in memory and learning.
