breathing, the ambient temperature of a room â you cannot experience these things directly because you are your brain, and your brain is currently housed in a bony isolation chamber with no contact to the outside world.
Your brain is in stark darkness inside your skull, yet you still see the light from your screen because of the light receptors in your eyes. Similarly, hairs in your ears help you to hear, and temperature receptors in your skin help you to detect temperature. Using these types of information, your body has evolved detection kits to help sense the outside world, to feed the brain accurate information about the environment.
There are temperature receptors all over your skin, although they are more common on the hairy parts of your body. And all over your skin there are also âmovementâ receptors to help you detect changes in pressure and texture (these are more concentrated in your hands and feet).
But what about the feeling of wetness? This seems to be a different case entirely, for there are no âwetâ receptors.
We can all agree on how important wetness/humidity is. Humidity governs the health of our skin, our lungs, and maybe our joints. Being wet can mean a sudden change in body temperature. And being wet is what sweating is all about; that is your body stopping itself from cooking to death.
A recent study published in the Journal of Neurophysiology discovered that humans cannot truly feel wetness. Since âwet receptorsâ never evolved along our line in the family tree, our brains must compensate with other clever tricks.
The researchers used cold-wet, cold-dry, warm-wet, and warm-dry treatments on participants who had various receptor nerves blocked. The study found that the brain integrates information about temperature and contact with the skin in order to infer wetness.
They discovered that participants were more likely to feel wet if the liquid was cold than if it were warm. And if participants had nerve blockers reducing movement sensitivity, they could only detect cold liquids as wet, not warm ones.
Once we process these two stimuli (heat and touch), our brains cross-reference those feelings with past experiences to determine that we are indeed getting wet.
Even completely fabricated perceptions such as âbeing wetâ can feel so real that weâd never thought to question them before. Researchers point out that a nose-bleed, where the liquid is at body temperature, can go undetected till we are informed. And, dare I say it, the slow compression of hairs can be what alerts us to a pants-wetting incident. Not that any of us can remember what that feels like, right?
How I rescued my brain
Light
Love bug
Wendy Zukerman
One whiff of the corpse and he was hooked. He tracked the scent to a lusty temptress, who had just killed her former lover, and quickly moved towards her. Without a thought for his fallen rival, the two spiders made sweet, sweet love.
Researchers at the University of Pittsburgh recently discovered that female grass spiders are more attractive to future mates if they cannibalise their previous lovers. It sounds deranged, but these cannibalistic femmes also tended to produce more eggs than females that stuck to eating crickets and, luckily for the second-comer, they only dined once.
Surely there is little more intriguing than the sex lives of spiders and insects. The splendour of their trickery and bizarre genitalia seems never-ending. But over the past few decades, watching the intimate moments of critters has helped scientists understand more than just smut. It has illuminated the forces of evolution, what it is to be âmaleâ and âfemaleâ, and even why sex exists at all. âThis is the sort of thing that everybody seems to be giggling about, but you should take it seriously,â says Menno Schilthuizen, an evolutionary biologist at the Naturalis Biodiversity Center in the Netherlands.
Earlier this year,