This is the first study to report a significant positive relationship between plasma BDNFlevels and brain activity in the right parietal cortex, which receives prominent afferentinput from the frontal cortex, during probabilistic association learning in healthy adults.Additionally, supporting our prediction of an altered relationship between plasma BDNF andbrain activity in schizophrenia, people with schizophrenia showed no relationship betweenplasma BDNF and neural activity in the frontal–parietal–striatal network. Here, BDNF is linked to schizophrenia.