Library · Physiology
Sensory adaptation
Make it clearer
There is one rule that every sensory receptor in the body follows, whether it sits in the skin, the eye or the ear: it adapts. That means that when a stimulus stays the same, without changing, the receptor gradually lowers the rate at which it sends its signals to the brain, those electrical bursts called action potentials.
That is why you put on a watch or a pair of socks and a few minutes later you no longer feel them. It is not that the receptor has broken down or switched off. It is in power-saving mode in the face of something that does not change, and the moment there is anything new it speaks up again: if the stimulus disappears, or if it changes intensity, the receptor responds once more.
And there is a limit at the other end. There comes a point of maximum stimulation where the response flattens out: no matter how much the stimulus rises, the receptor cannot fire any faster.
In brief
Adaptation is a property shared by all sensory receptors.
When a stimulus excites a receptor steadily, the rate of its action potentials drops.
Adapting is not shutting off: if the stimulus goes away or changes intensity, the receptor responds again.
You stop feeling the watch on your wrist until it shifts, and then you feel it again.
There is also a ceiling: at maximum stimulation the response flattens and the receptor cannot fire any faster.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Sensory Receptors, StatPearlsPublished
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