Temporal lobe activations of "feeling-of-knowing" induced by face-name associations.

"Feeling-of-Knowing" (FOK) refers to the sense of what one knows and is a component of the human metamemory system. We investigated the neural correlates of the FOK induced by face-name associations using the Recall-Judgment-Recognition paradigm. Data were gathered using event-related functional magnetic resonance imaging (fMRI). We analyzed the fMRI data with parametric analyses of six FOK ratings while compensating for the effects of unbalanced response latencies among trials ("variable duration parametric analysis"). Regions showing a significant linear relationships with the FOK ratings (FOK regions) were the bilateral ventral, dorsal, and anterior prefrontal regions; the medial frontal regions; the medial surface regions; the left parietal regions; the bilateral superior temporal and nearby regions; the right anterior temporal region; and the bilateral thalami/basal ganglia. Most of the active areas in the prefrontal regions were common to those found in our previous FOK studies of general knowledge (Kikyo, H., Ohki, K., Miyashita, Y., 2002. Neural correlates for feeling-of-knowing: an fMRI parametric analysis. Neuron 36, 177-186). However, in this study, we found robust activations of the temporal regions near to the regions that were related to the higher-order information processing of face images or semantic information processing of the to-be-recalled person. Those results suggest that the information related to the higher-order visual features of a face, which was represented in the temporal cortex, was activated by the top-down signal from the prefrontal cortex, and that this cooperation between the temporal and prefrontal cortices may contribute to the FOK.