Touch is a vital means of receiving information. Somatic senses are sometimes referred to as somesthetic senses, with the understanding that somesthesis includes the sense of touch, sense of position and movement, and depending on usage. The somatosensory system is a part of the sensory nervous system. The somatosensory system is a complicated system of sensory neurons and pathways that respond to changes at the surface or inside the body. The axons of sensory neurons, connect with or respond to, various receptor cells.
These neural receptor cells are stimulated by different stimuli such as heat and pain, giving a possible name to the responding sensory neuron, such as a thermoreceptor which provides information about temperature changes. Other types involve mechanoreceptors, chemoreceptors, and nociceptors and they send signals along a sensory nerve to the spinal cord where several sensory neurons may process them and then sent to the brain for further processing. Sensory receptors are located all over the body including the skin, epithelial tissues, muscles, bones and joints, internal organs, and the cardiovascular system.
The mapping of the body facades in the brain is called somatotopy. In the cortex, it is also related to as the cortical homunculus. This brain-surface map is not permanent, however. Dramatic shifts can occur in reply to stroke or injury. The human touch is delicate enough to feel the variation between surfaces that differ by just a single layer of molecules, according to investigators including one of Indian origin. Humans can quickly feel the difference between many common surfaces such as glass, metal, wood and plastic.
That is because these surfaces have different textures or draw heat away from the finger at various rates. However, researchers required studying if humans could identify the difference if they changed only the topmost layer of molecules.
“This is the greatest physical sensitivity that has ever been shown in humans,” stated Darren Lipomi, a professor at University of California (UC) San Diego in the US.
“Receptors processing responses from our skin are phylogenetically the most ancient, but far from being primitive they have had time to develop exceptionally subtle strategies for discerning surfaces,” said V S Ramachandran, from UC San Diego.
“This research is one of the earliest to show the range of sophistication and precise sensitivity of tactile sensations. It paves the way, perhaps, for an entirely new approach to tactile psychophysics,” Ramachandran concluded.
The brain is the only part of human body which controls everything. The sensations which we feel, and we react on are all instructions given by our mind. The human brain consists of many nerves which control our body from head to toe. Scientists right now researching on our sense of touch which involves the study of the brain, the most complicated part of the body and recent research shows that our mind can detect molecular differences in body. Though it is still under research.