In motion sickness, nausea and vomiting can be triggered via a pathway involving visceral afferents from the GI tract to which brain area?

In motion sickness, nausea and vomiting can be triggered via a pathway involving visceral afferents from the GI tract to which brain area?

• A. Reticular formation of the medulla
• B. Cerebellum
• C. Thalamus
• D. Frontal cortex

Answer: (A)

Motion sickness nausea and vomiting arise from a reflex that starts with visceral signals from the GI tract traveling to the brainstem. These afferents reach the area postrema and the nucleus tractus solitarius in the medulla, and from there the information is conveyed to the vomiting center within the medullary reticular formation. When this medullary vomiting center is activated, the coordinated motor events of vomiting are produced. The other brain regions mentioned—cerebellum for balance, thalamus as a sensory relay, and frontal cortex for higher-level processing—aren’t the primary initiators of the vomiting reflex, which is why the medullary reticular formation is the key site for this pathway.

Motion sickness nausea and vomiting arise from a reflex that starts with visceral signals from the GI tract traveling to the brainstem. These afferents reach the area postrema and the nucleus tractus solitarius in the medulla, and from there the information is conveyed to the vomiting center within the medullary reticular formation. When this medullary vomiting center is activated, the coordinated motor events of vomiting are produced. The other brain regions mentioned—cerebellum for balance, thalamus as a sensory relay, and frontal cortex for higher-level processing—aren’t the primary initiators of the vomiting reflex, which is why the medullary reticular formation is the key site for this pathway.