Monitoring of selections of visual stimuli and the primate frontal cortex.

This investigation shows that lesions confined to the middle sector of the dorsolateral frontal cortex, i.e. cytoarchitectonic areas 46 and 9, cause a striking impairment in the ability of non-human primates to recall which one from a set of stimuli they chose, without in any way affecting their ability to recognize that they had previously seen those stimuli. By contrast, lesions placed within the adjacent posterior dorsolateral frontal cortex affect neither recognition of visual stimuli nor recall of prior choices. These findings delineate the mid-dorsolateral frontal cortex as a critical component of a neural system mediating the monitoring of self-generated responses.