Kinetic parameters for the brain (kin, kout, kdeep_br_in, kdeep_br_out) were fitted using the brain concentration-time profiles for each compound according to the additive error model under the Naïve pooled algorithm in Phoenix 64, ver. 8.2.2.227 [32] (Figure ). For estimation of stable parameters, the range of values was set from 0.001 to 1 for kdeep_br_in and kdeep_br_out.