Researchers are trying to figure out why the brains of some older adults look 30 years younger than their peers.
While these so-called cognitively elite “SuperAgers” may be 80 or more years old, they have memories as sharp as those decades younger. SuperAgers were first identified in 2007 by scientists at Northwestern University’s Cognitive Neurology and Alzheimer’s Disease Center. A new study published in the Journal of Neuroscience is the first to quantify brain differences of SuperAgers compared to normal older people.
Their unusual brain signature has three common components when compared with normal persons of similar ages:
- thicker region of the cortex
- significantly fewer tangles (a primary marker of Alzheimer’s disease)
- whopping supply of a specific neuron—von Economo—linked to higher social intelligence
“The brains of the SuperAgers are either wired differently or have structural differences when compared to normal individuals of the same age,” says Changiz Geula, the study’s senior author and a research professor at the Cognitive Neurology and Alzheimer’s Disease Center. “It may be one factor, such as expression of a specific gene, or a combination of factors that offers protection.”
“Identifying the factors that contribute to the SuperAgers’ unusual memory capacity may allow us to offer strategies to help the growing population of ‘normal’ elderly maintain their cognitive function and guide future therapies to treat certain dementias,” says Tamar Gefen, the first study author and a clinical neuropsychology doctoral candidate.
What Brain Scans Show
MRI imaging and an analysis of the SuperAger brains after death showed that the anterior cingulate cortex of SuperAgers (31 subjects) was not only significantly thicker than the same area in aged individuals with normal cognitive performance (21 subjects), but also larger than the same area in a group of much younger, middle-aged individuals (ages 50 to 60, 18 subjects).
This region is indirectly related to memory through its influence on related functions such as cognitive control, executive function, conflict resolution, motivation, and perseverance.
Analysis of the brains of five SuperAgers showed the anterior cingulate cortex had approximately 87 percent less tangles than age-matched controls and 92 percent less tangles than individuals with mild cognitive impairment. The neurofibrillary brain tangles, twisted fibers consisting of the protein tau, strangle and eventually kill neurons.
The number of von Economo neurons was approximately three to five times higher in the anterior cingulate of SuperAgers compared with age-matched controls and individuals with mild cognitive impairment.
“It’s thought that these von Economo neurons play a critical role in the rapid transmission of behaviorally relevant information related to social interactions,” Geula says, “which is how they may relate to better memory capacity.” These cells are present in such species as whales, elephants, dolphins, and higher apes.
Grants from the National Institute on Aging and the Davee Foundation supported the work.