Chapter 9: Chemical Senses: Taste and Smell
A patient with multiple sclerosis suddenly developed impaired taste sensation. An MRI revealed a lesion in the left pontine tegmentum. Which of the following statements best describes the distribution of taste loss on the tongue produced by the lesion?
A. Left and right sides of tongue; anterior two thirds of each side
B. Left and right sides of tongue; posterior one third of each side
C. Left side of tongue, both anterior and posterior parts
D. Right side of tongue, both anterior and posterior parts
Comment: The ascending gustatory pathway is ipsilateral.
Which of the following cranial nerves does not provide any gustatory innervation of the tongue and oral cavity?
Comment: The XIIth nerve innervates tongue muscles.
The rostral solitary nucleus is to the caudal solitary nucleus, as
D. taste is to visceral sensations
A patient with multiple sclerosis has focal demyelination in the pontine tegmentum that damages the ascending gustatory pathway. Which of the thalamic nuclei listed below would be most directly influenced by this demyelination?
A. Ventral posterior lateral nucleus
B. Ventral posterior medial nucleus
D. Ventral medial posterior nucleus
Comment: The thalamic gustatory nucleus is the parvocellular division of the ventral posterior medial nucleus. Whereas the medial dorsal nucleus transmits taste information to the orbitofrontal cortex for integrating tastes and smells, it does not receive direct input from the ascending taste pathway.
A patient has a seizure disorder and has gustatory hallucinations. Which of the following brain regions is most likely to be directly involved in these hallucinations?