A Study to Investigate Safety and Tolerability, Pharmacokinetics and Pharmacodynamics of JNJ-64140284 in Healthy Participants

Inclusion Criteria:

Part 1 and 2:

- Healthy male participants between 18 and 58 years of age, inclusive

Part 1, 2 and 3:

- Participants must be healthy on the basis of clinical laboratory tests performed at screening. If the results of the serum chemistry panel, hematology, or urinalysis are outside the normal reference ranges, retesting of an abnormal lab value(s) that may lead to exclusion will be allowed once during the screening phase. The participant may be included only if the investigator judges the abnormalities or deviations from normal to be not clinically significant or to be appropriate and reasonable for the population under study according to both the investigator and to the Janssen Safety Physician, are acceptable

Part 3:

• Healthy male and female participants between 59 and 75 years of age, inclusive
• Participants must be healthy and medically stable on the basis of clinical laboratory tests (at screening) and physical and neurological examination (at screening and at admission to the clinical unit). If the participant is medically stable with medication, inclusion can be allowed on a case by case basis with written agreement of the sponsor's responsible safety physician
• Women must not be of childbearing potential (must be postmenopausal with amenorrhea for at least 12 months) or permanently sterilized (for example, tubal occlusion, hysterectomy, bilateral salpingectomy)

Exclusion Criteria:

Part 1, 2 and 3:

• Participants with a history of or current significant medical illness including (but not limited to) cardiac arrhythmias or other cardiac disease, hematological disease, lipid abnormalities, bronchospastic respiratory disease, diabetes mellitus, renal or hepatic insufficiency, thyroid disease, Parkinson's disease, infection, or any other illness that the Investigator considers should exclude the participant
• Participants with a serology positive for hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibodies or human immunodeficiency virus (HIV) antibodies
• Participants with a clinically significant acute illness within 7 days prior to study drug administration
• Donation of 1 or more units (approximately 450 milliliter [mL]) of blood or acute loss of an equivalent amount of blood within 90 days prior to study drug administration

Part 3:

- participants having a contraindication for spinal puncture including:

1. A relevant history of lower back pain or scoliosis or kyphosis and/or major (lumbar) back surgery (microdiscectomy is allowed) in the opinion of the investigator
2. Allergy to local anesthetics and/or iodine/disinfectants
3. Clinically significant abnormal values for coagulation at screening
4. Use of aspirin (even low dose) within 5 days prior to lumbar puncture
5. Use of low molecular weight heparin (LMWH) within 12 hours prior to lumbar puncture
6. Use of any anticoagulant treatment (besides LMWH described above) within 1 week prior to lumbar puncture
7. Has a topical infection or local dermatological condition at the puncture site prior to puncture
8. Has papilloedema or signs of increased intracranial pressure based on fundoscopy at screening