Specialized areas for value updating and goal selection in the primate orbitofrontal cortex.

The macaque orbitofrontal cortex (OFC) is essential for selecting goals based on current, updated values of expected reward outcomes. As monkeys consume a given type of reward to satiety, its value diminishes, and OFC damage impairs the ability to shift goal choices away from devalued outcomes. To examine the contributions of OFC's components to goal selection, we reversibly inactivated either its anterior (area 11) or posterior (area 13) parts.

Two-item same/different discrimination in rhesus monkeys (Macaca mulatta).

Almost all nonhuman animals can recognize when one item is the same as another item. It is less clear whether nonhuman animals possess abstract concepts of "same" and "different" that can be divorced from perceptual similarity. Pigeons and monkeys show inconsistent performance, and often surprising difficulty, in laboratory tests of same/different learning that involve only two items.