Face Processing Changes in Normal Aging Revealed by fMRI Adaptation

Abstract

We investigated the neural correlates of facial processing changes in healthy aging using fMRI and an adaptation paradigm. In the scanner, participants were successively presented with faces that varied in identity, viewpoint, both, or neither and performed a head size detection task independent of identity or viewpoint. In right fusiform face area (FFA), older adults failed to show adaptation to the same face repeatedly presented in the same view, which elicited the most adaptation in young adults. We also performed a multivariate analysis to examine correlations between whole-brain activation patterns and behavioral performance in a face-matching task tested outside the scanner. Despite poor neural adaptation in right FFA, high-performing older adults engaged the same face-processing network as high-performing young adults across conditions, except the one presenting a same facial identity across different viewpoints. Low-performing older adults used this network to a lesser extent. Additionally, high-performing older adults uniquely recruited a set of areas related to better performance across all conditions, indicating age-specific involvement of this added network. This network did not include the core ventral face-processing areas but involved the left inferior occipital gyrus, frontal, and parietal regions. Although our adaptation results show that the neuronal representations of the core face-preferring areas become less selective with age, our multivariate analysis indicates that older adults utilize a distinct network of regions associated with better face matching performance, suggesting that engaging this network may compensate for deficiencies in ventral face processing regions.

The cognitive neuroscience of ageing

“…This result is consistent with the idea of a compensatory mechanism whereby additional activity in task-relevant regions increases the ability of older adults to carry out the task. Similarly, another experiment examined face perception 48 and found a set of regions in right PFC and occipital cortex where increased activity was associated with better face recognition in older adults, but not a younger group. Furthermore, in a task requiring attention to right and left visual fields 49 , only old adults showed increased activity in bilateral PFC that was positively correlated with better performance.…”

“…Moreover, discrimination thresholds for distinguishing same from different faces were correlated with the degree of adaptation in the FFA across younger and older adults, indicating that this adaptation was important for behavior. A similar study 48 assessed adaptation in the FFA during presentation of faces that also varied in viewpoint (right/left orientation). Young adults showed the least activity when the same face was seen in the same viewpoint, more activity when the face or the viewpoint changed, and the most activity when both the face and viewpoint changed.…”

Hippocampal Brain Volume Is Associated with Faster Facial Emotion Identification in Older Adults: Preliminary Results

“…Previous studies that showed age-related difficulties in facial emotion identification have examined associations of this deficit with age differences in functional brain activation (Fischer et al, 2005, 2010; Gao et al, 2009; Lee et al, 2011; Ebner et al, 2012). It is proposed that multiple brain regions work together in order for face processing, independent of emotional valence, to occur (for review see Ruffman et al, 2008).…”

Motion facilitates face perception across changes in viewpoint and expression in older adults.

“…The recruitment of such additional areas may help compensate for age-related decline in the face processing network. Interestingly, Lee et al (2011) noted that "high performing" older adults (i.e., based on faster RT performance in a face matching task conducted outside the scanner) recruited a similar face network as younger adults. However, activation in this network was not suf ficient to support the matching of identity across views, as older adults who engaged this network did not reliably exhibit faster response times in this condition.…”