There’s been considerable debate about whether the human brain has the capacity to make new neurons into adulthood. Now, a recently published study offers some compelling new evidence that’s the case. In fact, the latest findings suggest that a healthy person in his or her seventies may have about as many young neurons in a portion of the brain essential for learning and memory as a teenager does.
As reported in the journal Cell Stem Cell, researchers examined the brains of healthy people, aged 14 to 79, and found similar numbers of young neurons throughout adulthood . Those young neurons persisted in older brains that showed other signs of decline, including a reduced ability to produce new blood vessels and form new neural connections. The researchers also found a smaller reserve of quiescent, or inactive, neural stem cells in a brain area known to support cognitive-emotional resilience, the ability to cope with and bounce back from stressful circumstances.
While more study is clearly needed, the findings suggest healthy elderly people may have more cognitive reserve than is commonly believed. However, the findings may also help to explain why even perfectly healthy older people often find it difficult to face new challenges, such as travel or even shopping at a different grocery store, that wouldn’t have fazed them earlier in life.
Tags: aging, aging brain, angiogenesis, autopsy study, brain, Brain Collection of the New York State Psychiatric Institute at Columbia University, cognition, dentate gyrus, elderly, glial cells, hippocampus, longevity, memory, neural progenitor cells, neural stem cells, neurogenesis, neurology, neurons, neuroplasticity, stereology
As a graduate student in the 1980s, Bruce Yankner wondered what if cancer-causing genes switched on in non-dividing neurons of the brain. Rather than form a tumor, would those genes cause neurons to degenerate? To explore such what-ifs, Yankner spent his days tinkering with neural cells, using viruses to insert various mutant genes and study their effects. In a stroke of luck, one of Yankner’s insertions encoded a precursor to a protein called amyloid. Those experiments and later ones from Yankner’s own lab showed definitively that high concentrations of amyloid, as found in the brains of people with Alzheimer’s disease, are toxic to neural cells .
The discovery set Yankner on a career path to study normal changes in the aging human brain and their connection to neurodegenerative diseases. At Harvard Medical School, Boston, Yankner and his colleague George Church are now recipients of an NIH Director’s 2016 Transformative Research Award to apply what they’ve learned about the aging brain to study changes in the brains of younger people with schizophrenia and bipolar disorder, two poorly understood psychiatric disorders.
Tags: aging brain, Alzheimer’s disease, amyloid, bipolar disorder, brain, brain imaging, FISSEQ, fluorescence in situ sequencing of RNA, induced Pluripotent Stem cells, iPSCs, mental illness, NIH Director’s 2016 Transformative Research Award, REST, REST gene, schizophrenia, transcription factor
When most people think of reprogramming something, they probably think of writing code for a computer or typing commands into their smartphone. Melanie Samuel thinks of brain circuits, the networks of interconnected neurons that allow different parts of the brain to work together in processing information.
Samuel, a researcher at Baylor College of Medicine, Houston, wants to learn to reprogram the connections, or synapses, of brain circuits that function less well in aging and disease and limit our memory and ability to learn. She has received a 2016 NIH Director’s New Innovator Award to decipher the molecular cues that encourage the repair of damaged synapses or enable neurons to form new connections with other neurons. Because extensive synapse loss is central to most degenerative brain diseases, Samuel’s reprogramming efforts could help point the way to preventing or correcting wiring defects before they advance to serious and potentially irreversible cognitive problems.
Tags: 2016 NIH Director’s New Innovator Award, 3D imaging, aging brain, brain, brain circuits, brain connectivity, brain diseases, eye, nervous system, neural circuitry, neural circuits, neurodegenerative disorders, neurology, remodeling synapses, retina, synapse, vision
Writers have The Elements of Style, chemists have the periodic table, and biomedical researchers could soon have a comprehensive reference on how to make neurons in a dish. Kristin Baldwin of the Scripps Research Institute, La Jolla, CA, has received a 2016 NIH Director’s Pioneer Award to begin drafting an online resource that will provide other researchers the information they need to reprogram mature human skin cells reproducibly into a variety of neurons that closely resemble those found in the brain and nervous system.
These lab-grown neurons could be used to improve our understanding of basic human biology and to develop better models for studying Alzheimer’s disease, autism, and a wide range of other neurological conditions. Such questions have been extremely difficult to explore in mice and other animal models because they have shorter lifespans and different brain structures than humans.
Tags: 2016 NIH Director’s Pioneer Award, addiction, aging, aging brain, Alzheimer’s disease, anxiety, autism, brain, brain cells, dopamine, fibroblasts, human neurons, iN cells, induced Pluripotent Stem cells, iPSCs, mental illness, neurobiology, neurology, neuronal subtypes, neurons, nicotinic receptors, serotonin, The Periodic Table, transcription factors, wellderly