Temperature perception experiment

Thermoreceptors are rapidly adapting receptors, which are divided into two types: cold and warm.

Thermoreceptor responsesWhen you put your finger into cold water, cold receptors depolarize quickly, then adapt to a steady state level which is still more depolarized than the steady-state. Warm receptors do the opposite: hyperpolarize quickly, then adapt to a slightly hyperpolarized state. This scenario is schematized in S&G Figure 10.14b.

When you move your finger to cold to warm water, cold receptors (which are already slightly depolarized), don't respond very strongly. Warm receptors do, and the response is stronger than normal, because they are slightly hyperpolarized. The brain perceives the warm water as hot because it is receiving more information from hot receptors than from cold.

The opposite response is observed from the thermoreceptors in the finger that is moved from hot to cold (greater response from cold receptors than warm).

The major point is that most receptors (including thermoreceptors) respond most strongly to a CHANGE in stimulus. Therefore a preceding experience that hyperpolarizes the receptor will cause the brain to interpret a new depolarizing stimulus as being stronger than if it "actually" is.