Incidental encoding of goal irrelevant information is associated with insufficient engagement of the dorsal frontal cortex and the inferior parietal cortex

Abstract

Previous studies have shown that goal-irrelevant distractors are incidentally encoded into long-term memory. Neuroimaging studies have suggested that the medial temporal and visual association regions are involved in incidental encoding of goal-irrelevant information. However, few studies have investigated prefrontal/parietal influence during the incidental encoding. The present study performed whole brain analysis to identify the brain regions involved in the incidental encoding of goal-irrelevant information. A face working memory (WM) task was administered with insertion of face distractors during the delay period. Following the WM task, a surprise recognition task was given in an MRI scanner. Recognition rate of distractors was higher than that of novel fillers. Recognition time was also faster in distractors than in novel fillers. Neuroimaging results showed less activation to distractors subsequently remembered than those forgotten in the middle and superior frontal regions and the lateral inferior parietal lobe including the angular gyrus and the temporoparietal regions. However, the left anterior hippocampus and the right fusiform gyrus showed greater activation to distractors subsequently remembered. Those findings suggest that insufficient engagement of the dorsal frontal cortex which regulates attentional control and the inferior parietal lobe which functions to reorient attention may allow goal-irrelevant information access to working memory and to be encoded into long-term memory.