This is a prospective, longitudinal study to examine time-dependent neurocognitive changes in patients with breast cancer receiving adjuvant chemotherapy. This study will assess chemotherapy-induced cognitive dysfunction. The researchers will recruit patients with localized breast cancer undergoing adjuvant chemotherapy for the first time and will test the effects of chemotherapy on patients' cognitive function utilizing a standardized neuropsychological battery. Patients scheduled for chemotherapy will be given a battery of neuropsychological undergo MRI evaluation prior to beginning chemotherapy and one month following completion of treatment.