How humans sense wetness decoded

Wetness perception is linked to our ability to sense cold temperature and tactile sensations such as pressure and texture, scientists have found.

PTI| Last Updated: Oct 03, 2014, 18:04 PM IST

London: Wetness perception is linked to our ability to sense cold temperature and tactile sensations such as pressure and texture, scientists have found.

Though it seems simple, feeling that something is wet is quite a feat because our skin does not have receptors that sense wetness.

Researchers have now proposed that wetness perception is intertwined with our ability to sense cold temperature and tactile sensations such as pressure and texture.

Researchers at Loughborough University and Oxylane Research also observed the role of A-nerve fibres - sensory nerves that carry temperature and tactile information from the skin to the brain - and the effect of reduced nerve activity on wetness perception.

They hypothesised that because hairy skin is more sensitive to thermal stimuli, it would be more perceptive to wetness than glabrous skin (eg, palms of the hands, soles of the feet), which is more sensitive to tactile stimuli.

The researchers exposed 13 healthy male college students to warm, neutral and cold wet stimuli.

They tested sites on the subjects' forearms (hairy skin) and fingertips (glabrous skin). The researchers also performed the wet stimulus test with and without a nerve block.

The nerve block was achieved by using an inflatable compression (blood pressure) cuff to attain enough pressure to dampen A-nerve sensitivity.

They found that wet perception increased as temperature decreased, meaning subjects were much more likely to sense cold wet stimuli than warm or neutral wet stimuli.

The research team also found that the subjects were less sensitive to wetness when the A-nerve activity was blocked and that hairy skin is more sensitive to wetness than glabrous skin.

These results contribute to the understanding of how humans interpret wetness and present a new model for how the brain processes this sensation, researchers said.

The study is published in the Journal of Neurophysiology.