The study is designed to evaluate the safety (side effects), tolerability, pharmacokinetics (how the drug is absorbed in the body, distributed within the body, and how it is removed from the body over time, ie, what the body does to the drug), and pharmacodynamics (what the drug does to the body) of JNJ-54861911. The study population will consist of approximately 38 healthy elderly participants divided among approximately 5 cohorts. For all participants the study will consist of 3 phases: eligibility screening examination phase (between 28 and 2 days prior to the first dose administration), a 14-day double-blind (Cohorts 1 to 4) or open-label (Cohort 5) treatment phase, and a follow-up examination phase (within 7 to 14 days after last dose administration). Participants who successfully complete the screening examination and are considered eligible to participate will be admitted to the clinical unit on Day -1 before administration of the study drug.