Specific sensory neurons can detect light touch, firm touch, pain, light brushing on the skin, sound waves, and photons of light.

“some Sensory neurons sense light touch other Sensory neurons sense firm touch other sensory neurons sense pain other Sensory neurons sense light brushing on the skin in fact you have Sensory neurons believe it or not that respond specifically to the light brushing of a hand across your skin any region of your body and if that particular region of your body happens to have hair on it and you stroke the skin in the direction that the hairs lay down we experience that as pleasurable whereas if you stroke in the direction opposite to the the way the hairs lay down we experience that as not pleasurable so these Sensory neurons respond in some cases for instance within the auditory system they respond to sound waves and your eye they respond to photons of light sometimes photons of light of particular wavelengths that we think of as red green blue and so on”