In a changeable environment, it is vital to be able to adapt one's behaviour rapidly depending on how successfully one's goals were achieved. Such adaptability has been seen as a cardinal aspect of cognitive control in the human literature (Allport, Styles and Hsieh, 1994; Bunge, 2004), as well as an indication in animal studies that responses are not merely being selected out of habit (though see Balleine and Dickinson, 1998 for more comprehensive criteria). Neuroimaging studies investigating task switching frequently find activation in parts of dorsomedial prefrontal cortex, including in dorsal ACC, when probing the regions that are active when people have to switch between response rules (Crone, Wendelken, Donohue and Bunge, 2006; Dove, Pollmann, Schubert, Wiggins and von Cramon, 2000; Liston, Matalon, Hare, Davidson and Casey, 2006; Rushworth, Hadland, Paus and Sipila, 2002). Surprisingly, however, monkeys with large lesions to the ACC, including both the sulcal and gyral regions, seem no more impaired at the time when switching between one of two response sets than when selecting an action with response rule well-established (Rushworth, Hadland, Gaffan and Passingham, 2003).
