There are age-related changes in neural connectivity during the encoding of positive, but not negative, information

Abstract

Introduction-Older adults often show sustained attention toward positive information and an improved memory for positive events. Little is known about the neural changes that may underlie these effects, although recent research has suggested that older adults may show differential recruitment of prefrontal regions during the successful encoding of emotional information. In the present study, effective connectivity analyses examined the network of regions that college-age and older adults recruited during the encoding of positive and negative images.Methods-Participants viewed positive and negative images while undergoing a functional magnetic resonance imaging (fMRI) scan. Structural equation modeling was used to compare young and older adults' connectivity among regions of the emotional memory network while they encoded negative or positive items.Results-Aging did not impact the connectivity among regions engaged during the encoding of negative information, but age differences did arise during the encoding of positive information. Most notably, in older adults, the ventromedial prefrontal cortex and amygdala strongly influenced hippocampal activity during the encoding of positive information. By contrast, in young adults, a strong thalamic influence on hippocampal activity was evident during encoding.Conclusions-These findings suggest that older adults' "positivity effect" may arise from agerelated changes in the interactions between affect-processing regions and the hippocampus during the encoding of positive information.

The cognitive neuroscience of ageing

“…This result was interpreted as evidence that older adults compensate for hippocampal deficits by relying more on the parahippocampal cortex. Similar results have been reported in studies that measured brain activity during successful encoding of words 91 , scenes 92 or objects 93 by comparing encoding activity for subsequently remembered versus forgotten stimuli. In these studies, functional connectivity during successful encoding between MTL regions and posterior regions, such as occipital cortex, was weaker in old adults, but connections between the MTL and the PFC were stronger in the older adults compared to a younger group.…”

Healthy aging is associated with increased neural processing of positive valence but attenuated processing of emotional arousal: an fMRI study

“…This is the first study to our knowledge to demonstrate reduced cortical reactivity to emotional arousal in healthy aging. Aging has been associated with the experience of fewer negative emotions (Gruenewald et al, 2008;Mroczek and Kolarz, 1998), as well as reduced neural processing of negative compared with positive emotional stimuli (Addis et al, 2010;Leclerc and Kensinger, 2008;Mather et al, 2004). Considering that negative emotional stimuli tend to be rated as more arousing than positive stimuli (Lang et al, 2008), and tend also to result in greater BOLD signal increases in emotional and visual brain regions than neutral or positive images (e.g., Lane et al, 1997;Mourão-Miranda et al, 2003), it is possible, based on our results, that an under-responsiveness in older adults to the effects of arousal may partly mediate the attenuation in their response to negative emotional stimuli.…”

Cognitive Reserve and Emotional Stimuli in Older Individuals: Level of Education Moderates the Age-Related Positivity Effect

“…Age-related positivity effects may be informed by a bias in the processing of emotional stimuli that emerges as previously unused neural networks are engaged due to age-related changes in functional organization of the brain. For instance, Addis et al (2010) have shown that, unlike in younger controls, successful encoding of positive information in older adults is accompanied by strong neural activity between typically emotionally-involved areas, such as the ventromedial pre-frontal cortex and the amygdala, and the hippocampus. These results suggest that emotional processing in older adults may be altered as a consequence of play an important role especially through its general support of neural compensation.…”

“…Moreover, older adults are thought to receive a memory boost for positively valenced information. However, this latter finding has been disputed, with some reports confirming it (Addis, Leclerc, Muscatell & Kensinger, 2010;Charles, Mather & Carstensen, 2003;Grady, Hongwanishkul, Keightley, Lee & Hasher, 2007;Kensinger, Garoff-Eaton & Schacter, 2007), while others have not found supporting evidence, or have qualified it (Emery & Hess, 2008;Kapucu, Rotello, Ready & Seidl, 2008;Kensinger, 2008).…”