The tissue radioactivity will be measured per organ for up to 5 hours after injection of up to 185 megaBecquerel (MBq) of 18F-JNJ-64413739 and corrected for attenuation by computed tomography (CT) transmission scans using PET/CT. These measurements will be used to estimate effective radiation dose per organ and total body.

The Distribution of 18F-JNJ-64413739 in brain will be measured by dynamic PET/magnetic resonance (MR) scans obtained from the time of injection for up to 120 minutes along with measurement of the tracer input function with arterial samples for intact tracer and metabolites to establish the total and regional compartmental kinetics and volume of distribution (V\[t\]) of 18F-JNJ-64413739.

Test Retest Variability within subjects will be assessed based on percent difference in V\[t\] following 18F-JNJ-64413739 PET/MR scans obtained at least 1 Week apart. V\[t\] will be the parameter for the estimated volume of distribution of the tracer derived from the kinetic model that best fits the data from Part B. It will be calculated by formula \[100\*abs (V\[t\]test - V\[t\]retest)/\[( V\[t\]test+ V\[t\]retest)/2\].

Descriptive statistics will be calculated for the plasma concentrations of JNJ-54175446.

Percent reduction in V\[t\] of 18F-JNJ-64413739 in brain regions of interest will be calculated by PET/MR scans obtained at pre and post treatment with single doses of JNJ-54175446.

The Cmax is the maximum observed plasma concentration.

Ctrough is defined as observed plasma concentration of drug just prior to the beginning or at the end of a dosing interval.

The Tmax is defined as actual sampling time to reach maximum observed concentration.

The AUClast is the area under the plasma concentration-time curve from time zero to the time of the last measurable (non-below quantification limit) concentration.

The AUC (0-infinity) is the area under the plasma concentration-time curve from time zero to infinite time, calculated as the sum of AUC(last) and C(last)/lambda(z); wherein AUC(last) is area under the plasma concentration-time curve from time zero to last quantifiable time, C(last) is the last observed quantifiable concentration, and lambda(z) is elimination rate constant.

Lambda (z) is first-order elimination rate constant associated with the terminal portion of the curve, determined as the negative slope of the terminal log-linear phase of the drug concentration-time curve.

The elimination half-life (t1/2) is the time measured for the plasma concentration to decrease by 1 half to its original concentration. It is associated with the terminal slope of the semi logarithmic drug concentration-time curve, and is calculated as 0.693/lambda(z).

Apparent total clearance is calculated as dose/AUC(0-infinity).

Apparent volume of distribution, calculated as dose/(lambda\[z\]\*AUC\[0-infinity\]).

Parent to metabolite ratio Cmax is defined as the ratio of individual Cmax values between parent and metabolite.

Parent to metabolite ratio (AUC \[Last\]) is defined as ratio of individual (AUC \[Last\]) values between parent and metabolite.

Parent to Metabolite Ratio (AUC \[infinity\]) is defined as the ratio of individual (AUC \[infinity\]) values between parent and metabolite.

The Cmax is the maximum observed plasma concentration.

The Tmax is defined as actual sampling time to reach maximum plasma concentration.

The AUC(0-t) is the area under the plasma concentration-time curve from time zero to any time 't'.

The AUC (0-infinity) is the area under the plasma concentration-time curve from time zero to infinite time, calculated as the sum of AUC(0-last) and C(last)/lambda(z); wherein AUC(0-last) is area under the plasma concentration-time curve from time zero to last quantifiable time, C(last) is the last observed quantifiable concentration, and lambda(z) is elimination rate constant.

Lambda(z) is first-order elimination rate constant associated with the terminal portion of the curve, determined as the negative slope of the terminal log-linear phase of the drug concentration-time curve.

The elimination half-life (t1/2) is the time measured for the plasma concentration to decrease by 1 half to its original concentration. It is associated with the terminal slope of the semi logarithmic drug concentration-time curve, and is calculated as 0.693/lambda(z).

Relative bioavailability, calculated as individual Cmax and AUC treatment ratios (for the comparison of capsule to suspension formulation).

An adverse event is any untoward medical event that occurs in a participant administered an investigational product, and it does not necessarily indicate only events with clear causal relationship with the relevant investigational product.

The Cmin is the minimum observed plasma concentration.

The (Ctrough) is the plasma concentration before dosing or at the end of the dosing interval of any dose other than the first dose in a multiple dosing regimen.

The Cavg,ss is calculated as area under the plasma concentration-time curve during a dosing Interval (AUC\[tau\]) divided by the dosing interval (tau).

The AUCtau is the measure of the plasma drug concentration from time zero to end of dosing interval. It is used to characterize drug absorption.

The AUC(0-t) is the area under the plasma concentration-time curve from time zero to any time 't'.

The Cmax is the maximum observed concentration.

Total clearance of drug after extravascular administration, uncorrected for absolute bioavailability

Creatinine clearance was calculated by Cockroft-Gault formula. Creatinine clearance is equal to 140 minus age multiplied by weight and constant (1 for men and 0.85 for women) divided by creatinine in (micro mole per liter).