alternative_right shares a report from ScienceAlert: According to a study of 38 adult human brains donated to science, superagers — people who retain exceptional memory as they age — have roughly twice as many immature neurons as their peers who age more typically. Moreover, people with Alzheimer’s disease show a marked reduction in neurogenesis compared to a normal baseline. […]
Led by researchers at the University of Illinois Chicago, the team set out to examine a variety of postmortem hippocampal tissue samples to see if they could identify markers of neurogenesis — and if different groups had any notable differences. The brain samples were donated from five groups: eight healthy young adults, aged between 20 and 40; eight healthy agers, aged between 60 and 93; six superagers, aged between 86 and 100; six individuals with preclinical Alzheimer’s pathology, aged between 80 and 94; and 10 individuals with an Alzheimer’s diagnosis, aged between 70 and 93. The young healthy adult brain tissue was first analyzed to establish the neurogenesis pathways in the adult brain. Then, they analyzed 355,997 individual cell nuclei isolated from the hippocampus, searching for three different stages of cell development: Stem cells, which can develop into neurons; neuroblasts, which are stem cells in the process of that development; and immature neurons, on the verge of functionality. The results were striking.
“Superagers had twice the neurogenesis of the other healthy older adults,” [says neuroscientist Orly Lazarov of the University of Illinois Chicago]. “Something in their brains enables them to maintain a superior memory. I believe hippocampal neurogenesis is the secret ingredient, and the data support that.” That’s an interesting result on its own, but the data from the individuals with preclinical Alzheimer’s pathology and Alzheimer’s diagnoses is where the real meat of the study sits. In the preclinical group, subtle molecular changes hinted that the system supporting new neuron growth was beginning to falter. In the Alzheimer’s group, a clear drop in immature neurons was evident. A genetic analysis of the nuclei also showed that superager neural cells have increased gene activity linked to stronger synaptic connections, greater plasticity, and brain-derived neurotrophic factor, a critical protein for neural survival, growth, and maintenance. Taken together, these three things can be interpreted as resilience. The research has been published in the journal Nature.