Noticing familiar objects in real world scenes: The role of temporal cortical neurons in natural vision

During natural vision, the brain efficiently processes views of the externa l world as the eyes actively scan the environment. To better understand the neural mechanisms underlying this process, we recorded the activity of ind ividual temporal cortical neurons while monkeys looked for and identified f amiliar targets embedded in natural scenes. We found a group of visual neur ons that exhibited stimulus-selective neuronal bursts just before the monke y's response. Most of these cells showed similar selectivity whether effect ive targets were viewed in isolation or encountered in the course of explor ing complex scenes. In addition, by embedding target stimuli in natural sce nes, we could examine the activity of these stimulus-selective cells during visual search and at the time targets were fixated and identified. We foun d that, during exploration, neuronal activation sometimes began shortly bef ore effective targets were fixated, but only if the target was the goal of the next fixation. Furthermore, we found that the magnitude of this early a ctivation varied inversely with reaction time, indicating that perceptual i nformation was integrated across fixations to facilitate recognition. The b ehavior of these visually selective cells suggests that they contribute to the process of noticing familiar objects in the real world.