Touch: Communicating the Self and the World

  Several important sensory organs in the human body are located in the head. The mouth allows you to taste, the nose allows you to smell, the eyes allow you to see, and the ears allow you to hear. But there is another sense that is also important, and that is touch. It can tell us the difference in how we feel when we stroking a cat’s fur with our fingers and touching the spikes of a cactus, and is an important way of communicating between ourselves and the world.
Tactile experience in life

  When your body is poked or touched, receptor cells in your skin sense the touch and send signals to nerve cells and the brain to let you know where on your body you have been poked or touched. Different parts of the brain respond to touch in the fingers, arms, legs, and other body parts, but fingertips are particularly sensitive to touch. A study showed that some men are more sensitive than women when it comes to touch, but some men are more sluggish than women. The study also found that age was not a factor affecting tactile perception, and the degree of tactile sensitivity did not differ by age.
  When you want to get a good feel for something, like how soft a cat’s soft fur is, you touch it with your fingers, not your arms or the backs of your hands. This is because the fingertips are more sensitive to touch, and there are far more tactile receptors on the fingers than on the arms or the back of the hand. Highly sensitive fingers can help us with many delicate tasks, from sending text messages quickly to performing delicate surgical procedures. Sensitive fingertips also help us with tasks such as typing, dressing, and babysitting a kitten.
  Of course, having a large number of nerve endings and highly sensitive fingers requires the brain to reserve more space to process all the information from the nerves in that area, so the area of ​​the brain that is used to sense and process the tactile response from the fingertip touching the hair is much more The area used to sense bugs crawling on the legs is much larger.
  Tactile receptors are found all over the body. The fingertips and face of the human body can feel touch, and the soles of the feet and knees can also feel touch. Extensive touch is an evolutionary necessity, and without it, we wouldn’t be able to sense when a toe is hit or the skin is burned, leading to more serious bodily harm.
  Our skin, as well as our organs, bones and muscles, are full of different receptor cells. Each receptor cell is connected to a sensory neuron that sends information back to the spinal cord and to the brain, which processes the touch the receptors feel to determine whether you’re petting a cat or touching a cactus.
  Vision fools our eyes, and sounds and smells easily fool our ears and noses, but what about touch? It might be a little harder to fool us. Scientists are working on haptic devices—techniques that mimic human touch to “trick” our sense of touch, allowing us to experience real touch in practical applications such as virtual reality and telemedicine.
Artificial skin simulates touch

  Scientists have been working on technologies and devices to develop haptic applications for years, but touch is a very subtle sensation that is distinct from sight and hearing. We can enhance and expand our visual senses through cameras and monitors to communicate over long distances; sound can be amplified through microphones and speakers and delivered to our ears. Simulating and extending haptic experience is a bigger challenge, but research on simulating haptics, such as artificial skin haptic devices, has made initial progress in haptic research and applications.
  Engineers have developed a wearable device that simulates human touch, which has a wide range of applications, such as robotic surgery and deep-sea exploration.
  Australian engineers have developed a tactile-simulating device made of a new type of artificial skin that fits over our fingers like a glove, interacting with the skin to simulate touch, allowing people to perceive objects they don’t actually touch. Such haptic devices have many potential uses. Wearing these gloves, surgeons can “touch” patients who seek medical treatment in faraway places and make more accurate diagnoses. In the deep sea or space, people can “touch” distant objects through tactile information transmitted by robots. Disabled people with prosthetic limbs can also use this haptic device to make the prosthesis feel real.
  The researchers also plan to add the ability to sense heat or cold to the device, allowing it to sense not only the sensory stimuli of force, but also temperature. If people want to have the real experience of touching ice in space, the future may be a dream come true.

Touch means a lot to us

  David Julius and Arden Pataptian have been awarded the 2021 Nobel Prize in Physiology or Medicine for their work on temperature- and touch-related receptors. Their research identified the presence of receptors in nerve cells that detect heat, cold and pressure, and identified some proteins called “receptors.” This protein transmits sensory signals from the skin and other organs to the brain, such as the scorching sensation of chili peppers or the burning sensation of a burning stove, the cooling sensation of peppermint, and even the sensation of warmth when hugging each other. Comes with a warm touch.
  Feeling touch is one of the basic functions of the nervous system and is our response to our surroundings. For example, in the event of a fire, or in extreme cold, the skin’s thermoreceptors warn us of the danger of burns or frostbite by feeling extremely hot or cold to the touch. Tactile receptors are important for sensing the position of our body parts in space, and without these tactile receptors we would not be able to stand, touch or perceive the environment around us.
  Scientists knew that such receptors existed long before the work of David Julius and Arden Pataptien and had been searching for them. Eventually, the two Nobel laureates came up with some ingenious ways to find them.