Neuroscientists have revealed that we cannot tickle ourselves (the gargalesis type) essentially because we can’t surprise our own brain. During a tickle, the
skin’s nerve endings shoot electrical signals to the somatosensory cortex, a part of the brain that processes
touch. Meanwhile, the anterior cingulate cortex analyzes these signals as either harmful or playful. But in the back part of the brain, the cerebellum gives you away. It tells your cortex that you are about to attempt a self-tickle, and not to worry, it should suppress the signals from the tickle. So there is a brain
system in place that analyzes the sensory input together with the motor output, basically telling us whether what we feel is due to ourselves or others. And in doing so, it also helps us understand how the brain separates “me” from “them.” In fact, some
people with dissociative disorders
like Schizophrenia can tickle themselves silly. Being able to differentiate the actions of others and ourselves is central to our sense of self.