Two adult rhesus monkeys (Macaca mulatta) were used for the experiments. All procedures for animal care and experimentation were approved by the Institute Animal Care and Use Committee and complied with the Public Health Service Policy on the humane care and use of laboratory animals. A plastic head holder and plastic recording chamber were fixed to the skull under general anesthesia and sterile surgical conditions. The recording chamber was placed over the fronto-parietal cortex, tilted laterally by 35 degrees, and was aimed at the SNc and VTA. Two search coils were surgically placed under the conjunctiva of the eyes. The head holder, the recording chamber and the eye coil connectors were all embedded in dental acrylic that covered the top of the skull and were connected to the skull by acrylic screws. We conditioned two monkeys using a Pavlovian procedure with an appetitive US (liquid reward) and an aversive US (airpuff). During the Pavlovian procedure, we recorded the activity of dopamine neurons in and around the SNc and VTA. We estimated the position of the SNc and VTA by MRI and identified dopamine neurons by their electrophysiological properties. After the end of recording sessions in one monkey, we confirmed the recording sites histologically. We analyzed anticipatory licking, anticipatory blinking and neuronal responses during the Pavlovian procedure. We focused on three kinds of neuronal responses: 1) responses elicited by CS presentation, 2) responses elicited by US delivery, and 3) responses elicited by US omission. Details of the Pavlovian procedure, identification of dopamine neurons, analysis methods, and histological procedure can be found in Full Methods.