Neural encoding of wetness perception in the cortex.

Perception depends on the representation of external information in the cortex. This information enters the nervous system thanks to receptor proteins in your sensory neurons. These receptors transform external energy into neural activity.

It follows that, if you do not have receptors sensitive to an environmental property, you cannot perceive such property.

For example, humans are not able to sense electric fields, whereas some fish can because they have electroreceptors.A sense required for survival is wetness due to its role in thermoregulatory responses.

Unlike insects, humans lack hygroreceptors sensitive to the level of moisture of the skin, yet we have clear sensations of wetness. So, how do we feel wetness?

Researchers think that these sensations emerge from the integration of thermotactile signals in the cortex, but the location or cellular encoding of wetness in the cortex is unknown. Therefore, I propose to study the neural basis of wetness sensations in mice.

The mouse is an ideal mammalian model for this because their thermotactile system is similar to ours and tools to measure neuronal activity can be combined with behaviour.

Crucially, researchers have recently found a co-localised representation of thermotactile stimuli in the mouse cortex.First, I will develop wet stimulators for use in mice based on designs from human studies. Second, I will measure wetness sensations in mice by developing a novel perceptual task.

Third, I will use calcium imaging techniques to identify and study cortical neurons activated during wetness sensations. Finally, I will use optogenetics to provide a causal relationship between neural activity and wetness sensations.

This project will advance our understanding of how wetness sensations emerge through cortical activity, even in the absence of a wetness receptor.

The research output will advance our understanding of brain function, but also will be of interest to the clothing, cosmetic and virtual reality industries.