Orbitofrontal cortex is activated during breaches of expectation in tasks of visual attention

Although information processing limitations encourage the evolution of brain systems that extract sameness and repeat established responses, advanced species have developed complementary neural systems for the rapid detection of deviations from sameness and for inhibiting inappropriate automatic response tendencies1. The prefrontal cortex is thought to have a particularly critical, executive role in detecting deviations from familiar patterns and inhibiting automatic responses2. Here we used positron–emission tomography (PET) to demonstrate that prefrontal cortex was activated when the learned and expected stimulus associations that guide behavior were violated, requiring inhibition of the prepared response and redirection of the focus of attention, in variants of a classic task of visual spatial orienting of attention3.