Motion sickness reflex arc bypasses the area postrema in cats

Area of Science:

• Neuroscience
• Physiology
• Vestibular System Research

Background:

• Motion sickness, or motion-induced vomiting, is a complex physiological response.
• The area postrema, a brainstem structure, has been implicated in emetic reflexes.

Purpose of the Study:

• To investigate the role of the area postrema in the reflex arc of motion-induced vomiting.
• To determine if ablation of the area postrema affects susceptibility to motion sickness.

Main Methods:

• Cats were exposed to vertical sinusoidal oscillation on a platform.
• Two groups of cats underwent chronic ablation of the area postrema: motion-untested and motion sickness-susceptible.
• Postoperative susceptibility to motion sickness was assessed.

Main Results:

• Motion sickness occurred in all previously untested cats after area postrema ablation.
• Four out of five previously susceptible cats experienced motion sickness postoperatively.
• Operated cats showed significantly higher susceptibility to motion sickness compared to controls.

Conclusions:

• The area postrema is not an essential component in the reflex pathway for motion-induced vomiting.
• Ablation of the area postrema appears to enhance susceptibility to motion sickness.
• Damage surrounding the area postrema may influence the observed effects on motion sickness susceptibility.