The Neuroscience of Superaging and Youthful Memory Power

Superagers have stronger functional connectivity between different brain areas.

Posted Sep 26, 2019

In 2012, Marsel Mesulam of Northwestern University published a landmark paper that explored the brain architecture associated with age-defying youthful memory capacity in a handful of 80+ year-olds who seemed to have freakishly good powers of memory. Mesulam is credited with coining the term "superaging" and "superagers."

Over the past few years, the neuroscience of superaging has been investigated more thoroughly by a team of researchers in Boston affiliated with Harvard Medical School and Northeastern University that we'll explore in this post.

 wavebreakmedia/Shutterstock
Source: wavebreakmedia/Shutterstock

My mom—who is in her late-80s and prides herself on playing Mahjong, Bridge, and Scrabble better now than she did in her 40s—opened my eyes to the term "superaging." As a superager herself, Mom keeps me updated on science-based articles about the topic via email. In 2017, she gave me a heads up about a New Year's Day article in the New York Times, "How to Become a Superager."

This NYT opinion piece by Lisa Feldman Barrett, who is a lecturer in psychiatry at Harvard Medical School (and holds other positions at Northeastern), recaps a neuroimaging study (Sun et al., 2016) that Barrett conducted with colleagues at Harvard's Massachusetts General Hospital (MGH). This neuroimaging study compared the brain architecture of so-called "superagers" with "typical" agers.

In a previous post, "Superagers Pursue Life with Gusto, Harvard Study Finds," I reported on these initial findings (2016) on superaging from MGH.

A few years ago, Harvard Medical School's multi-faceted research on superagers identified some structural differences that make their age-defying brains unique along with some character traits associated with superaging.

From a lifestyle and mindset perspective: Superagers, in general, thrive on pushing against their limits and derive pleasure from tackling challenges that require laser-like focus and full engagement. Research shows that, overall, superagers seem to approach life with "vim and vigor" and tend to bounce back from goof-ups or setbacks quickly. They are also inclined to "grin and bear it" when the going gets tough without much complaining.

From a brain science perspective: Superagers appear to have more gray matter volume and "cortical thickness" in brain regions correlated with memory performance. The robust gray matter volume and structural integrity of these brain regions were also linked to better functioning of the default mode network (DMN) and salience networks (SN).

A Superager's Brain Connectivity Looks Like a Younger Adult in fMRI

Taken together, we now know that the DMN and SN are associated with youthful memory in superaging based on a combination of optimized gray matter structure and white matter functional connectivity.

These findings (Zhang et al., 2019) were recently published in the journal Cerebral Cortex. A September 9 news release about this study summed up the findings with a headline: "Superagers over 80 have the memory and brain connectivity of twenty-somethings." 

As co-author Alexandra Touroutoglou from the MGH Department of Neurology explains, "Superagers show not just youthful brain structure, but youthful connectivity as well." 

This study used functional magnetic resonance imaging (fMRI) to investigate brain wave synchronization in the default mode network and salience network in a cohort of "superagers" when they were in a resting state.

In a summary of their findings, the authors write: "Both the default mode network and salience network in superagers had stronger connectivity than typical older adults and similar connectivity as younger adults. Superagers performed similarly to young adults and better than typical older adults in recognition and episodic memory tasks."

"These networks ebb and flow, or oscillate, whether you're in a resting state or engaged in a task," co-author Bradford Dickerson, who is an associate professor of neurology and director of the Frontotemporal Disorders Unit in the MGH Department of Neurology, said in the release. "Our prediction was that typical older adults would have less synchronization in these brain waves—less efficient networks—but that superagers would have networks as efficient as the young adults. And that's what we found."

The next phase of this research will use fMRI to observe how superagers' brains become engaged when they're not in a resting state but, instead, are performing memory or cognitive tasks.

Touroutoglou hopes that this series of studies on the neuroscience of superaging will "provide basics for future researchers to develop biomarkers of successful aging."

She also points out that the million-dollar question remains: Do superagers start off with "bigger and better" brain structure and functional connectivity than typical agers, or are they somehow more resilient to the brain changes associated with aging?

Future research on superagers and superaging will do a deeper dive into the role of genetics and other lifestyle factors such as staying physically active, diet, social connectedness, and other daily habits associated with resilience across a lifespan.

"We hope to identify things we can prescribe for people that would help them be more like a superager," Brad Dickerson concluded. "It's not as likely to be a pill as more likely to be recommendations for lifestyle, diet, and exercise. That's one of the long-term goals of this study—to try to help people become superagers if they want to."

References

Jiahe Zhang, Joseph M Andreano, Bradford C Dickerson, Alexandra Touroutoglou, Lisa Feldman Barrett. "Stronger Functional Connectivity in the Default Mode and Salience Networks Is Associated With Youthful Memory in Superaging." Cerebral Cortex (First published online: May 6, 2019) DOI: 10.1093/cercor/bhz071

Felicia W. Sun, Michael R. Stepanovic, Joseph Andreano, Lisa Feldman Barrett, Alexandra Touroutoglou and Bradford C. Dickerson. "Youthful Brains in Older Adults: Preserved Neuroanatomy in the Default Mode and Salience Networks Contributes to Youthful Memory in Superaging." Journal of Neuroscience (First published: September 14, 2016) DOI: 10.1523/JNEUROSCI.1492-16.2016

Emily J. Rogalski, Tamar Gefen, Junzi Shi, Mehrnoosh Samimi, Eileen Bigio, Sandra Weintraub, Changiz Geula and M.-Marsel Mesulam. "Youthful Memory Capacity in Old Brains: Anatomic and Genetic Clues from the Northwestern SuperAging Project." Journal of Cognitive Neuroscience (First published online: December 2, 2012) DOI: 10.1162/jocn_a_00300