If you choose to join this study, you will come in for a screening visit to make sure that you are eligible to participate. During this visit, you will have an MRI scan taken of your brain and do some cognitive testing. If you are eligible to continue, you will get a random assignment (like drawing numbers from a hat) to 1 of 3 brain training groups. You will do your brain training at home. Your group assignment might be:

• High-frequency puzzles: If you are in this group, you will do computerized crossword puzzles 4 times per week (30 minutes per session). OR
• Low-frequency puzzles: If you are in this group, you will do computerized crossword puzzles once per week (30 minutes per session). OR
• Health education training: If you are in this group, you will do health education training once per week (30 minutes per session).

This study lasts for about 78 weeks (1.5 years). Your assigned brain training will last for 12 weeks. After the 12 weeks are done, we will schedule you to come in for follow-up visits at 12, 32, 52, and 78 weeks for cognitive testing. Around the times you come in for follow-up visits, you will do some "booster sessions" of your assigned brain training at home before the visits. To participate, you will need to have a study partner who is close to you and who can speak with the study team about how you are doing while you are taking part in the study. Your study partner will need to come to our clinic with you one time to sign the consent form, but then they can complete all of their study interviews by phone. We will pay you for your time on the study. You will be compensated $75 for the screening visit, then $100 for each follow-up visit (5 visits) and $100 per MRI scan (2 scans). Study partners will receive $50 for the initial visit to sign consent and complete the first interview, and they will then be compensated $25 for each subsequent phone interview (4 interviews).