Figure 3.

Interaction of prefrontal cortex (PFC) and inferotemporal cortex (IT) is necessary for the processing of temporally complex events. (a) Schematic diagram of the tasks (stimuli not presented to scale). Monkeys performed two-choice concurrent visual object discriminations in both tasks, with a 2 s delay between choice and reward delivery. In task 2I (‘two-item’), this delay was filled by another visual object on the screen, whereas in task UD (‘unfilled delay’) the delay was not associated with any visual object. See Ref. [73] for further information regarding monkeys learning about groups of stimuli. (b) Comparison of performance of monkeys in these visual discrimination tasks following crossed unilateral ablations of the PFC and IT (PFCxIT). Bars represent mean errors to criterion of the group, and letters represent individual monkeys’ scores that have contributed to that mean. The same letter shows the same monkey's scores in the two tasks. Monkeys with PFCxIT were impaired relative to control monkeys (with no ablations) at the 2I task, in which the choice and intervening item had formed a temporally complex event, but were not impaired at the UD task, in which all contingencies were the same as task 2I except for the fact that there was no temporally complex element. It is notable that the control monkeys find the temporally complex task (2I) easier – the sequence element presumably helping to bridge the gap to the reward, something that does not occur in the UD task. It is the loss of this facilitation that seems to cause the impairment in the monkeys with PFC/IT ablations because these monkeys perform as if there were no sequence element. Adapted from Ref. [56].