Abstract
Recently, fMRI studies have reported that activity in the Fusiform Face Area (FFA) is reduced or eliminated in the absence of attention. In these studies, an “attended” condition (where subjects make a behavioral report on face images) is compared to an “unattended” condition where another task is performed and the faces are behaviorally irrelevant. It is unclear, however, how activity correlates with behavioral performance (since there is no required performance for unattended faces), and thus if the observed decrease in activity is purely due to the lack of top-down attention or if it is explained by the behavioral irrelevance of the faces. Recently, using a dual-task paradigm, we showed that the attentional cost associated with face-gender discrimination is minimal. When subjects reported the gender of a peripherally presented face while performing an attentionally engaging task at fixation, their performance suffered but little compared to when attention was available. In this condition, minimal attentional resources are available to the peripheral face, but it remains behaviorally relevant. Thus we are in a position to determine how neural activity varies with behavioral performance and attentional modulation. We use fMRI to examine the effects of attention on brain activation using the dual-task paradigm. Preliminary results show that FFA activity is mostly unaffected by whether subjects perform the face task alone (peripheral-task condition) or in conjunction with the central task (dual-task condition). Interestingly, the activity is decreased in the “central-task” condition when the faces are still present but are behaviorally irrelevant. This latter result is consistent with previous reports: neural activity is affected by the behavioral relevance of stimuli. In addition, however, the fact that FFA activity is maintained in the dual-task condition indicates that attentional manipulation per se leaves both performance and neural activity unaffected.
NSF,ERC,Keck Foundation