Neurofeedback is the use of biofeedback techniques to re-train brainwave activity. By targeting particular types of brainwave activity in specific frequency bands or particular brain locations, the brain can learn to change its activity which is reflected in changes in behavior. Neurofeedback training has been used most successfully to retrain for greater attention or focus, to calm the nervous system whether for electrical disturbances like seizures or for emotional disturbances like panic and anxiety. It has been used to retrain mood, clear cognition after injury whether physical trauma like a closed head injury or chemical ones such as chemotherapy. It has even been used successfully for retraining learning issues and autistic symptoms.