Caloric Nystagmus is stimulated by what kind of environmental change?

Caloric nystagmus is a physiological response that occurs when temperature changes in the inner ear stimulate the vestibular system. When a temperature difference is introduced, for example, by instilling warm or cold water into the ear canal, it creates a temperature gradient in the inner ear. This results in changes in the density of the fluid (endolymph) within the semicircular canals, leading to the sensation of motion and resulting in nystagmus, which is an involuntary eye movement.

The vestibular system is highly sensitive to temperature changes, and this physiological mechanism is often used in clinical settings to assess vestibular function. In contrast, other options like contrast in visual stimuli, physical motion, and adjustment of gravity do not directly induce caloric nystagmus as they involve different sensory pathways and mechanisms that do not specifically trigger the response related to temperature changes in the inner ear.