TAK-653 (9-[4-(cyclohexyloxy)phenyl]-7-methyl-3,4-dihydropyrazino[2,1-c]thiadiazine 2,2-dioxide) is a small-molecule positive allosteric modulator of the AMPA-type glutamate receptor discovered at Takeda. It is also designated NBI-1065845 in later clinical work. Its originators describe it as an AMPA receptor potentiator with minimal agonistic activity, meaning that it enhances receptor responses to glutamate while producing little receptor activation on its own. Published research covers receptor pharmacology in recombinant cells, neurons and brain slices, rodent behavioural and safety models, a nonhuman primate chronic stress model, and phase 1 studies in healthy volunteers.