Which brainstem nucleus receives signals from the tongue and mouth?

The nucleus of the solitary tract plays a crucial role in processing sensory information from the tongue and mouth, particularly relating to taste and other visceral sensations. Located in the medulla oblongata of the brainstem, this nucleus receives afferent inputs from the cranial nerves responsible for taste sensation—mainly the facial (VII), glossopharyngeal (IX), and vagus nerves (X).

This nucleus integrates and relays information regarding the taste and other sensory modalities related to the oral cavity to other brain regions, facilitating the perception and response to taste stimuli. Its involvement in visceral sensations extends beyond taste, allowing it to participate in reflexive responses associated with eating and swallowing, thereby emphasizing its importance in sensory processing within the brainstem.

The other options do not directly relate to the processing of signals from the tongue and mouth. The nucleus accumbens is primarily involved in reward processing and the regulation of motivated behavior. The cortex of the insula is associated with a range of functions, including the integration of sensory and emotional information, but it does not have the same direct role in receiving signals specifically from the tongue and mouth as the nucleus of the solitary tract does. The mediodorsal nucleus is primarily involved in cognitive functions and memory,