Summary: A new study explains how a subset of older adults maintain youthful memory abilities and identifies the brain networks that support this resilience.
Source: Harvard
Researchers’ images reveal resilient brain networks in “super-agers”
While some degree of memory decline is common with age, a growing body of research highlights older adults who remain remarkably sharp. A team at Massachusetts General Hospital, affiliated with Harvard Medical School, examined older adults whose memory performance matched that of people decades younger and identified preserved brain anatomy in networks tied to memory and attention.
The study, published in the Journal of Neuroscience, represents an early step in a research program led by Bradford C. Dickerson (Harvard Medical School and director of the Frontotemporal Disorders Unit at MGH) and Lisa Feldman Barrett (Department of Psychiatry, MGH, and University Distinguished Professor at Northeastern University). The work aims to discover why some older adults retain youthful cognitive abilities and which neural circuits make that possible.
Participants and study design
Investigators enrolled 40 older adults aged 60 to 80. Seventeen of them—termed “super-agers” for the study—performed on memory tests at the level of people in their 20s, while 23 showed memory performance typical for their age. For comparison, the study also included 41 younger adults aged 18 to 35. Super-agers were defined using standardized verbal memory testing, allowing direct comparisons with young adults.
Key imaging findings
Structural brain scans showed that many regions in super-agers resembled those of young adults. Although cortical thinning and volume loss are common with normal aging, super-agers had preserved thickness in multiple areas. In particular, nodes of the default mode network—important for encoding and retrieving memories—such as the hippocampus and medial prefrontal cortex, were thicker in super-agers than in typical older adults. In some regions, cortical thickness in super-agers was indistinguishable from that of young adults.
The researchers also examined the salience network, which helps identify and focus on important information. Several salience-network regions, including the anterior insula and orbitofrontal cortex, showed preserved cortical thickness in super-agers compared with their peers.
Network interactions linked to memory performance
Beyond preserved structure, the study found correlations between regional brain size and memory ability among older adults. One of the strongest relationships involved a region at the junction of the salience and default mode networks—the para-midcingulate cortex—previously recognized as a hub facilitating communication across networks. The findings suggest that not only the integrity of individual regions but also effective interaction between networks supports healthy cognitive aging.
“We believe that effective communication between these networks is very important for healthy cognitive aging,” said Alexandra Touroutoglou of MGH Neurology and Harvard Medical School, a co-author of the study.
Implications for age-related memory decline
Identifying neuroanatomical features that protect against memory decline could point to new approaches for preserving cognition and treating age-related memory loss. Bradford Dickerson emphasized the potential importance of studying people who age well: understanding how some individuals maintain strong memory into their seventies and beyond may reveal clues to prevent or slow typical memory decline and some forms of dementia.
Study: Youthful Brains in Older Adults: Preserved Neuroanatomy in the Default Mode and Salience Networks Contributes to Youthful Memory in Superaging
Summary of findings: The investigators examined cortical thickness and hippocampal volume in older adults who demonstrated memory performance comparable to much younger adults. They found preserved cortical thickness within key nodes of two intrinsic brain networks—the default mode network (involved in memory encoding and retrieval) and the salience network (involved in attention and executive function). Hippocampal volume was also better preserved in super-agers. Within the older adult group overall, thickness in regions such as the anterior temporal cortex, rostral medial prefrontal cortex, and anterior midcingulate cortex correlated with memory performance, as did hippocampal volume. These results indicate that preserved neuroanatomy in paralimbic and limbic nodes of the default mode and salience networks supports attentional, executive, and mnemonic processes underlying strong memory function in some older adults.
Significance: Although cortical structure and memory typically decline with age, a subset of older adults retain youthful memory abilities. This research shows those individuals often lack the usual atrophy in specific brain regions tied to memory and attention. Preserved structure in the default mode and salience networks is associated with better memory among older adults, suggesting targets for future studies on resilience to cognitive aging.
Authors: Felicia W. Sun, Michael R. Stepanovic, Joseph Andreano, Lisa Feldman Barrett, Alexandra Touroutoglou, and Bradford C. Dickerson.