To analyze neuron activity, we combined data from both monkeys because they were qualitatively identical for our major findings. We defined the response to the fixation point as the discharge rate during 75–325 ms after the fixation point onset minus the discharge rate during 300–0 ms before

the onset. The response to the sample stimulus was defined as the discharge rate during 75–300 ms after the sample stimulus onset minus the discharge rate during 300–0 ms before the onset. The response to the search array was defined as the discharge rate during 100–350 ms after the search array onset minus the discharge rate during 300–0 ms before the onset. The choice-aligned response was determined as the discharge rate during 125–375 ms after the Z-VAD-FMK solubility dmso choice onset minus the discharge rate during 300–0 ms before the onset. The choice onset was determined as the time when the monkey’s eye

click here position entered into a target window and subsequently stayed within the window to choose the target. These time windows were determined on the basis of the averaged activity of dopamine neurons. Specifically, we set the time windows such that they include major parts of the responses. To calculate spike density functions (SDFs), each spike was replaced by a Gaussian curve (σ = 15 ms). At the end of the recording session in monkey F, we selected representative locations of electrode penetration and made electrolytic microlesions no (14 μA and 40 s). Then monkey F was deeply anaesthetized with pentobarbital sodium and perfused with 10% formaldehyde. The brain was blocked and equilibrated with 30% sucrose. Frozen sections were cut every 50 μm in the coronal plane. The sections were immunostained for tyrosine hydroxylase (TH; mouse anti-TH antibody, 1:1,000, Millipore; biotin-SP donkey anti-mouse IgG, 1:1,000, Jackson) and counterstained with neutral red. We thank E. Bromberg-Martin and K. McCairn for comments on the earlier version of the manuscript, and D. Takahara for technical assistance. This research was supported by Funding

Program for Next Generation World-Leading Researchers (LS074) to M.M. from Cabinet Office, Government of Japan; Grants-in-Aid for Scientific Research (22800036) to M.M. from the Ministry of Education, Science, Sports, Culture, and Technology of Japan; the Takeda Science Foundation to M.M.; and the Uehara Memorial Foundation to M.M. “
“During natural vision, humans categorize the scenes that they encounter. A scene category can often be inferred from the objects present in the scene. For example, a person can infer that she is at the beach by seeing water, sand, and sunbathers. Inferences can also be made in the opposite direction: the category “beach” is sufficient to elicit the recall of these objects plus many others such as towels, umbrellas, sandcastles, and so on.