Age-related neural differences in affiliation and isolation

Abstract

While previous aging studies have focused on particular components of social perception (e.g., theory of mind, self-referencing), little is known about age-related differences specifically for the neural basis of perception of affiliation and isolation. This study investigates age-related similarities and differences in the neural basis of affiliation and isolation. Participants viewed images of affiliation (groups engaged in social interaction) and isolation (lone individuals), as well as nonsocial stimuli (e.g., landscapes), while making pleasantness judgments and undergoing functional neuroimaging (BOLD fMRI). Results indicated age-related similarities in response to affiliation and isolation in recruitment of regions involved in theory of mind and self-referencing (e.g., temporal pole, medial prefrontal cortex). Yet age-related differences also emerged in response to affiliation and isolation in regions implicated in the theory of mind, as well as self-referencing. Specifically, in response to isolation versus affiliation images, older adults showed greater recruitment than did younger adults of the temporal pole, a region that is important for retrieval of personally relevant memories utilized to understand others' mental states. Furthermore, in response to images of affiliation versus isolation, older adults showed greater recruitment than did younger adults of the precuneus, a region implicated in self-referencing. We suggest that age-related divergence in neural activation patterns underlying judgments of scenes depicting isolation versus affiliation may indicate that older adults' theory of mind processes are driven by retrieval of isolation-relevant information. Moreover, older adults' greater recruitment of the precuneus for affiliation versus isolation suggests that the positivity bias for emotional information may extend to social information involving affiliation.

Figure 1

Participants viewed and made ratings of pleasantness for three different stimuli conditions: affiliation (images of groups of individuals interacting; left), isolation (images of a lone individual; center), or non-social (images of objects and landscapes; right).

Figure 2

A conjunction analysis determined age similarities, or regions of shared activation, between younger and older adults when perceiving social as compared to non-social scenes (2A). Social perception produced greater activity in the temporal pole (left), medial prefrontal cortex (center), and the amygdala (right). In 2B, a conjunction analysis determined neural regions of shared activation between younger and older adults in response to affiliation in comparison to isolation. Perception of affiliation produced greater activity in the precuneus (left) while perception of isolation produced greater activity in superior/inferior parietal regions (right).

Figure 3

Age-related differences in response to the conjunction of two types of social perception (affiliation and isolation) were compared (3A). MarsBaR region of interest analyses reflect peak activation in each brain region categorized by age group and social perception condition (affiliation, isolation), depicted in bar graphs. Younger adults showed greater activity in the hippocampus, relative to older adults, in response to social (across both affiliation and isolation) vs. non-social scenes (3A). The age differences in response to affiliation vs. isolation (3B & 3C) indicate that in the paracentral lobule and precuneus, younger adults show relatively more activity in response to isolation (relative to affiliation) while older adults show a greater response to affiliation (relative to isolation) (3B). In the temporal pole the opposite pattern is found with younger adults showing relatively more activity in response to affiliation (relative to isolation) while older adults showed a greater response to isolation (than affiliation) (3C).