Summary: Older adults classified as “superagers” show stronger functional connectivity in both the default mode network (DMN) and the salience network (SN) compared with typical older adults, and their connectivity resembles that seen in young adults. Superagers also outperform typical older adults and perform similarly to young adults on recognition and episodic memory tasks.
Source: Mass General
New research published in the journal Cerebral Cortex finds that stronger functional connectivity — the coordinated activity between brain regions — is associated with preserved, youthful memory in some older adults, often referred to as “superagers.” Those individuals exhibit the strongest connectivity within key brain networks studied.
This paper is the second of three linked studies that aim to understand why a subset of older adults in their 60s, 70s, 80s and beyond maintain cognitive function at levels comparable to much younger people. Earlier work from the same team showed that superagers have greater cortical thickness in certain brain regions that contribute to learning, memory encoding, storage, and retrieval. The current study extends those findings by examining how brain regions interact as cohesive networks rather than as isolated structures.
“Communication between brain regions declines on average with normal aging,” said Alexandra Touroutoglou, Ph.D., an investigator in the MGH Department of Neurology and the Athinoula A. Martinos Center for Biomedical Imaging. “Superagers not only retain more youthful brain structure, they also retain more youthful patterns of connectivity.”
The study compared three groups: superagers, typical older adults aged roughly 60 to 80, and young adults aged 18 to 35. Using resting-state functional magnetic resonance imaging (fMRI), researchers measured the synchronization of spontaneous brain activity within two large-scale networks: the default mode network (DMN), which supports internally focused cognitive processes like memory retrieval and self-referential thought, and the salience network (SN), which helps detect and prioritize important stimuli and coordinate responses.
“These networks oscillate continuously whether you are resting or performing a task,” said Bradford C. Dickerson, MD, director of MGH’s Frontotemporal Disorders Unit. “We hypothesized that typical older adults would show diminished synchronization — less efficient network function — while superagers would show connectivity patterns closer to young adults. Our results supported that prediction.”
Participants included 41 young adults (average age 24.5 years) and 40 older adults (average age 66.9 years). Superaging was defined by youthful performance on a standardized memory recall test, the California Verbal Learning Test (CVLT). In addition to the resting-state scan, participants completed a separate visual–verbal recognition memory task.
Key findings: within both the DMN and SN, superagers displayed stronger intrinsic connectivity than typical older adults, and their connectivity closely matched that of the younger group. Behaviorally, superagers performed like young adults and significantly better than typical older adults on the recognition memory task, showing that their preserved memory abilities generalize across different types of episodic memory tests. Importantly, stronger connectivity within each network independently predicted better memory performance across older individuals. Measures of functional connectivity accounted for unique variance in memory that went beyond what could be explained by youthful brain anatomy alone.
The team plans to analyze fMRI data collected while participants perform memory and other cognitive tasks to further understand how these networks support successful memory function. Future work aims to clarify whether superagers are born with advantageous brain structure and connectivity or whether they develop greater resilience against age-related decline. Researchers will also explore the potential contributions of genetics, physical activity, diet, social engagement, and other lifestyle factors known to influence cognitive resilience.
“Our long-term goal is to identify actionable strategies that help people preserve memory as they age,” said Dickerson, who is also an associate professor of neurology at Harvard Medical School. “It’s unlikely that a single pill will be the answer. More promising are practical recommendations around lifestyle, diet, and exercise that may promote the brain’s resilience.”
Source:
Mass General
Media Contacts:
Terri Janos – Mass General
Image Source:
The image is in the public domain.
Original Research: Closed access
“Stronger Functional Connectivity in the Default Mode and Salience Networks Is Associated With Youthful Memory in Superaging.” Authors: Jiahe Zhang, Joseph M. Andreano, Bradford C. Dickerson, Alexandra Touroutoglou, Lisa Feldman Barrett. Cerebral Cortex. DOI: 10.1093/cercor/bhz071
Abstract (summary)
Superagers are older adults who retain youthful memory abilities. Previous structural studies identified DMN and SN regions with greater cortical thickness in superagers that correlate with memory. This study examined intrinsic functional connectivity in DMN and SN across young adults and older adults, including superagers. Superagers showed stronger connectivity within both networks than typical older adults and similar connectivity to young adults. They also performed comparably to young adults and better than typical older adults on recognition memory, indicating preserved episodic memory across tasks. Stronger network connectivity predicted better memory performance in older adults and explained unique variance beyond structural brain measures, advancing understanding of superaging as a model of successful cognitive aging.