Age-related alterations of brain network underlying the retrieval of emotional autobiographical memories: an fMRI study using independent component analysis.

Ruiyang Ge,Li Yao,Dahua Wang,Yan Fu,Zhiying Long

doi:10.3389/fnhum.2014.00629

Abstract

Normal aging has been shown to modulate the neural underpinnings of autobiographical memory and emotion processing. Moreover, previous researches have suggested that aging produces a “positivity effect” in autobiographical memory. Although a few imaging studies have investigated the neural mechanism of the positivity effect, the neural substrates underlying the positivity effect in emotional autobiographical memory is unclear. To understand the age-related neural changes in emotional autobiographical memory that underlie the positivity effect, the present functional magnetic resonance imaging (fMRI) study used the independent component analysis (ICA) method to compare brain networks in younger and older adults as they retrieved positive and negative autobiographical events. Compared to their younger counterparts, older adults reported relatively higher positive feelings when retrieving emotional autobiographical events. Imaging data indicated an age-related reversal within the ventromedial prefrontal/anterior cingulate cortex (VMPFC/ACC) and the left amygdala of the brain networks that were engaged in the retrieval of autobiographical events with different valence. The retrieval of negative events compared to positive events induced stronger activity in the VMPFC/ACC and weaker activity in the amygdala for the older adults, whereas the younger adults showed a reversed pattern. Moreover, activity in the VMPFC/ACC within the task-related networks showed a negative correlation with the emotional valence intensity. These results may suggest that the positivity effect in older adults' autobiographical memories is potentially due to age-related changes in controlled emotional processing implemented by the VMPFC/ACC-amygdala circuit.

Highlights

Human aging is accompanied by the decline of various cognitive abilities and alterations in the function and structure of the neural circuits underlying sensorimotor, cognitive and emotion processing
Results of regression analysis A regression analysis revealed that only one cluster in the VMPFC/anterior cingulate cortex (ACC) (Figure 6; region marked by the red circle; MNI coordinate: 3, 38, 4) showed a significant negative correlation with valence intensity
Our results suggest that older adults’ “positivity effect” in emotional autobiographical retrieval may stem from changes in emotional processing implemented by the VMPFC/ACC and amygdala

Summary

Introduction

Human aging is accompanied by the decline of various cognitive abilities and alterations in the function and structure of the neural circuits underlying sensorimotor, cognitive and emotion processing. In contrast to younger adults, older adults tended to report a stronger recollective experience (Janssen et al, 2011) and take relatively more time to gain access to the target events (Addis et al, 2011; St Jacques et al, 2012). Functional neuroimaging studies investigate ng autobiographical memory under normal aging have observed increased activity in the hippocampus, parietal and occipital cortex during autobiographical memory recollection (Maguire and Frith, 2003; Donix et al, 2010), reduced activation in the prefrontal cortex and reduced coupling between the ventrolateral prefrontal cortex and hippocampus during search and elaboration phases of autobiographical memory retrieval (St Jacques et al, 2012), and decreased activity in the medial temporal lobes and precuneus during the construction of autobiographical events (Addis et al, 2011; St-Laurent et al, 2011)

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