Their results suggest that you can't tickle yourself because your brain predicts the tickle from information it already has about, say, your fingers moving. Certain areas of the brain including the secondary somatosensory cortex and the anterior cingulate cortex are less active when you tickle yourself. The cerebellum controls balance and coordination, so it might be involved in predicting what effect movement of one part of the body has on other body parts. Anytime scientists learn something about how the brain works normally, it sheds light on what might be happening when something goes wrong with the brain. In this case, information about how the brain distinguishes self-generated touch from touch generated externally could help unravel one of the mysteries of schizophrenia .
Schizophrenics often have trouble distinguishing external events from self-generated ones.
What they do has nothing to do with me. People with schizophrenia often believe that they are being touched, even when no one is actually touching them. To support this theory of a defect in self-monitoring in schizophrenics, Frith and colleagues compared patients who had symptoms of schizophrenia with patients who did not.