Chapter 16: The Limbic System and Cerebral Circuits for Reward, Emotions, and Memory
A patient with a rare memory disorder has an MRI. The neuroradiologist notes that the only significant change is that the hippocampal formation is degenerated. Which of the following statements best describes the most likely effect this would have on the image of the ventricular system?
A. There would be no change to the ventricular system because the degeneration is localized to the hippocampal formation.
B. This would be accompanied by shrinkage of the lateral ventricle.
C. This would be accompanied by enlargement of the entire ventricular system.
D. This would be accompanied by enlargement of only the ventral, or temporal, horn of the lateral ventricle system.
Comment: Cerebral degenerative disorders generally result in loss of neurons without concomitant replacement with more glia, or glial scaring. As a consequence, the affected brain regions shrink in size. Because the cranial cavity is of a fixed volume, this is accompanied by an increase in the nearby ventricle/aqueduct. Recall in Chapters 1 and 14, we viewed MRIs of patients with Alzheimer disease and Huntington disease, where neural degeneration was associated with clear increases in the volume of the lateral ventricles.
Limbic cortical areas do not engage in primary sensory or motor functions. Rather, they integrate information, often from several cortical regions that are interconnected with the hippocampal formation, amygdala, or both. Which of the following is not considered a limbic cortical area?
A. Anterior cingulate cortex
C. Posterior insular cortex
Comment: The posterior insular cortex is the primary cortical area for aspects of pain, visceral sensation, and vestibular function.
Which of the following best indicates a function of the orbitofrontal cortex?
A. Integration of olfactory and gustatory messages important for deciding to ingest something
B. Localization of stimuli in the space around us
C. Identification of familiar faces
D. Helping to establish the emotional aspect of pain
Comment: Face identification is a function of the caudal-medial temporal lobe. Stimulation localization is mediated by the posterior parietal lobe. Emotional aspects of pain are mediated by the anterior cingulate gyrus.
Which part of the hippocampal formation is noted for ...