Abstract
"Feeling-of-Knowing (FOK)" is a sense of knowing a word before recalling it, and the FOK provides us clues to understanding the mechanisms of human metamemory systems. We investigated neural correlates of the FOK induced by face-name associations using the Recall-Judgment-Recognition paradigm with event-related functional magnetic resonance imaging (fMRI). Written informed consent was obtained from all the fifteen subjects in accordance with the Declaration of Helsinki, and the experimental procedure was approved by the institutional review board of the University of Tokyo School of Medicine. A 1.5 Tesla scanner system was used for the functional imaging. A T2*-weighted gradient echo echo-planar imaging was used to measure the blood-oxygen level dependent contrast (TR, 3.0 sec; TE, 40 msec) in 22 horizontal slices (voxel size, 4x4x5 mm; inter-slice gap, 1 mm). We analyzed the fMRI data with parametric analyses of six FOK ratings. The 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. The activations in the temporal regions may reflect higher order information processing of face images as well as semantic information processing of the person to-be-recalled, and the information extracted by these processes may contribute to the FOK. [Jpn J Physiol 54 Suppl:S191 (2004)]
