The eyes have it: hippocampal activity predicts expression of memory in eye movements.
Although there is widespread agreement that the hippocampus is critical for explicit episodic memory retrieval, it is controversial whether this region can also support indirect expressions of relational memory when explicit retrieval fails. Here, using functional magnetic resonance imaging (fMRI) with concurrent indirect, eye-movement-based memory measures, we obtained evidence that hippocampal activity predicted expressions of relational memory in subsequent patterns of viewing, even when explicit, conscious retrieval failed. Additionally, activity in the lateral prefrontal cortex and functional connectivity between the hippocampus and prefrontal cortex were greater for correct than for incorrect trials. Together, these results suggest that hippocampal activity can support the expression of relational memory even when explicit retrieval fails and that recruitment of a broader cortical network may be required to support explicit associative recognition.
Hannula
Deborah E
DE
Center for Neuroscience, University of California, Davis, 1544 Newton Court, Davis, CA 95618, USA. dehannula@ucdavis.edu
Ranganath
Charan
C
D000704:Analysis of Variance; D001245:Association Learning / Q000502:physiology; D003463:Cues; D053483:Eye Movement Measurements; D005133:Eye Movements / Q000502:physiology*; D005145:Face; D005260:Female; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D009434:Neural Pathways; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D017397:Prefrontal Cortex / Q000502:physiology; D011930:Reaction Time; D021641:Recognition, Psychology / Q000502:physiology; D013702:Temporal Lobe / Q000502:physiology; D013997:Time Factors