The Regulation of Cognitive Control following Rostral Anterior Cingulate Cortex Lesion in Humans
1,21,21,2Giuseppe di Pellegrino, Elisa Ciaramelli and Elisabetta Làdavas
12 Università di Bologna, Italy, Centro Studi e Ricerche in Neuroscienze Cognitive, Cesena, Italy
Reprint requests should be sent to Giuseppe di Pellegrino, Dipartimento di Psicologia,
40127 Bologna, Italy, or via e-mail: Università di Bologna, Viale Berti Pichat 5 -
The contribution of the medial prefrontal cortex, particularlythe anterior cingulate cortex (ACC), to cognitive control remains controversial. Here, we examined whether the rostral ACC isnecessary for reactive adjustments in cognitive control followingthe occurrence of response conflict [Botvinick, M. M., Braver,T. S., Barch, D. M., Carter, C. S., & Cohen, J. D. Conflictmonitoring and cognitive control. Psychological Review, 108,624–652, 2001]. To this end, we assessed 8 patients withfocal lesions involving the rostral sector of the ACC (rACC patients), 6 patients with lesions outside the frontal cortex(non-FC patients), and 11 healthy subjects on a variant of theSimon task in which levels of conflict were manipulated on atrial-by-trial basis. More specifically, we compared Simon effects(i.e., the difference in performance between congruent and incongruenttrials) on trials that were preceded by high-conflict (i.e.,incongruent) trials with those on trials that were precededby low-conflict (i.e., congruent) trials. Normal controls andnon-FC patients showed a reduction of the Simon effect when the preceding trial was incongruent, suggestive of an increasein cognitive control in response to the occurrence of responseconflict. In contrast, rACC patients attained comparable Simoneffects following congruent and incongruent events, indicatinga failure to modulate their performance depending on the conflictlevel generated by the preceding trial. Furthermore, damageto the rostral ACC impaired the posterror slowing, a furtherbehavioral phenomenon indicating reactive adjustments in cognitivecontrol. These results provide insights into the functional organization of the medial prefrontal cortex in humans and itsrole in the dynamic regulation of cognitive control.
J. Cogn. Neurosci. 2007 19: 275-286