(A, B) Chemogenetic - DREADD reporter system. Lenti-HA-hM4Di injections targeted to right amygdala in monkey. A: Injection location depicted on a coronal section. B: Baseline [11C]DCZ binding (SUV) reveals contrast between the injection site (marked with an arrow) and the surrounding brain. (C, D) Chemogenetic - PSAM reporter system. AAV injection site in mouse left dorsal striatum (AAV-PSAM4-GlyR-EGFP). C: approximate injection location. D: PET image of mouse brain after [18F]ASEM injection, showing striatal localization of PSAM4-GlyR. (E,F) PKM2 reporter system. AAV9-EF1A-PKM2 targeted to the ventral tegmental area / substantia nigra of mouse brain. E: injection location. F: [18F]DASA-23 binding; arrow indicates region of radiotracer uptake. (G, H) ecDHFR reporter system. Recombinant ecDHFR-EGFP reporter protein was expressed in mouse somatosensory cortex after transduction with AAV-DJ. G: injection location. H: [18F]FE-TMP binding; arrow indicates area of accumulation of the radiotracer. Figures B, D, F and H were adapted from [51], [53], [56] and [57] respectively.