A closer look
Cerebellar activity actively predicts your own movements and dampens the sensory response, making it completely impossible for you to genuinely tickle yourself no matter how hard you try. Your brain acts as an extreme micromanager, constantly keeping track of exactly where your hands are going and canceling out the element of surprise required to trigger a tickle response. If you actually can tickle yourself, it is often considered a clinical sign of schizophrenia or other neurological disorders where the brain fails to recognize its own self-generated actions. It is incredibly frustrating that our central nervous system has all these powerful defense mechanisms, yet we remain entirely vulnerable to the tickle attacks of annoying relatives. Our brain essentially refuses to let us have any unapproved fun with our own nerve endings
