Study is enrolling newly diagnosed breast cancer patients about to start chemotherapy and age-matched control participants. The investigator is trying to better understand the prevalence of cognitive difficulties in cancer patients receiving chemotherapy compared to the general population as well as what biological mechanisms may play a role in the development of these difficulties. Patients will be asked to complete six assessments over the course of approximately 5 months. Assessments 1,3, 4.5 and 5 include computerized and paper and pencil cognitive testing as well as blood draws. Assessments 2 and 4 only involve the collection of a blood sample. An optional sub study is offered after Assessment 1. It involves a research brain MRI at Assessment 4.5 and cognitive testing and another research brain MRI at Assessment 6.