What is damaging the cells? And do chemotherapy and radiation cause different sorts of problems?
A. The radiation [studies] are a little older, and I think they have paved the way for allowing the chemotherapy studies on the toxicity on the human brain. The mechanisms of how radiation affects the human brain are somewhat different than toxicity from chemotherapy. We know that patients who are exposed to radiation treatment show signs of inflammation. And inflammation itself in the brain may cause a whole cascade of negative side effects. One of the most important side effects that we see, in terms of symptoms, is cognitive impairment that may propagate even years after radiation treatment has been finished. Radiation may impact the rejuvenation of brain cells and mainly has negative effects on the newborn neurons. We have learned in the past decade that the brain is actually able to repair itself to some degree, contrary to what was originally thought. This alone was a revolutionary finding — to see that there are certain areas in the brain called germinal zones that are on a dail
