title: The orbitofrontal cortex is involved in emotional enhancement of memory: evidence from the dementias.
abstract: The enhancing effect of emotion on subsequent memory retrieval is well established. Patients with frontotemporal dementia show profound emotion processing difficulties, yet the extent to which such deficits attenuate emotional enhancement of memory remains unknown. Here, we studied the intersection between emotion and memory using a visual forced-choice recognition test for negative and neutral stimuli in 34 patients with frontotemporal dementia compared with 10 patients with Alzheimer's disease and 15 control subjects. Control subjects and patients with Alzheimer's disease recognized more emotional than neutral items, as demonstrated by a significant interaction between emotion and memory for true recognition. This emotional enhancement effect was notably absent in the frontotemporal dementia cohort, with comparable recognition performance regardless of emotional content. Voxel-based morphometry analyses revealed distinct neural substrates for overall memory versus emotional memory performance. Overall memory performance correlated with the hippocampus, precuneus and posterior cingulate, regions crucial for successful episodic memory performance. Emotional enhancement of memory, by contrast, was associated exclusively with the integrity of the right orbitofrontal and subcallosal cortex. Our findings demonstrate differential disruption of emotional enhancement of memory in neurodegenerative disorders, and point toward the potentially pivotal role of the orbitofrontal cortex in supporting the successful retrieval of emotionally charged negative stimuli.
authors.affiliation: 1 Neuroscience Research Australia, Sydney, Australia.
authors.forename: Fiona
authors.initials: F
authors.lastname: Kumfor
authors.forename: Muireann
authors.initials: M
authors.lastname: Irish
authors.forename: John R
authors.initials: JR
authors.lastname: Hodges
authors.forename: Olivier
authors.initials: O
authors.lastname: Piguet
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology*; D003704:Dementia / Q000473:pathology / Q000503:physiopathology*; D004644:Emotions / Q000502:physiology*; D005260:Female; D006624:Hippocampus / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged
keywords: Alzheimer’s disease; episodic memory; frontotemporal dementia; orbitofrontal cortex, emotion