The causes of many brain diseases, such as epilepsy and schizophrenia, are unknown. Researchers such as Dr. Kurt Haas are exploring the possibilities that abnormal brain development in the prenatal stage may play a role. Using a powerful gene delivery technique, Dr. Haas is investigating how nerve cell activity contributes to brain development, specifically, the effect of altered levels (i.e. too much or too little) of activity on the structure and function of neuronal circuits. This research could lead to more specific and effective interventions to prevent abnormal circuits from forming during prenatal development, and also to treat adults with schizophrenia or epilepsy.