# Can Aging Brains Generate New Neurons? Insights from Recent Research
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Understanding Neurogenesis in Aging Brains
The long-held belief that older individuals cannot learn new skills may not hold true for brain function. Recent findings published in Nature Medicine challenge this notion by exploring whether adult brains are capable of producing new neurons, particularly in the hippocampus—an area critical for memory formation. This region is significantly impacted by Alzheimer's disease, raising questions about the potential benefits of enhancing neuronal connections in older adults facing this condition.
Despite ongoing debates, it remains uncertain whether neurogenesis, or the generation of new neurons, persists in the hippocampus beyond childhood. Researching the brain is notoriously complex due to the scarcity of well-preserved human brain tissue and the varying methodologies employed to identify newly formed neurons. This has led to conflicting conclusions regarding neurogenesis in adults.
The New Study's Findings
This recent study adds valuable insight to the discourse surrounding Alzheimer's disease. By employing meticulous tissue collection and advanced processing techniques, researchers discovered thousands of new neurons in the hippocampus of 13 healthy individuals aged between 43 and 87, noting a modest decline in neurogenesis with age (approximately 30% reduction from the youngest to the oldest participants). In stark contrast, 45 Alzheimer’s patients aged 52 to 97 exhibited significantly fewer newly formed neurons, averaging 30% less than their healthy counterparts. Notably, individuals with more severe Alzheimer's presented with a marked decrease in neurogenesis, indicating a progressive decline that correlates with disease severity. This observation implies that Alzheimer's is not merely an age-related condition but is associated with distinct pathological changes.
Potential for New Therapeutic Approaches
Could stimulating neuron production in the hippocampus pave the way for innovative treatments? This prospect emerges as a glimmer of hope following recent disappointing news regarding the failure of another Alzheimer's drug in Phase III clinical trials. Previous studies in mouse models have indicated that certain medications and physical activity can mitigate cognitive impairments. However, further research is crucial to replicate these findings and assess their applicability to human subjects.
Managing Correspondent: Chelsea Weidman Burke
Press Articles: Debate about birth of new neurons in adult brains extends to Alzheimer’s disease, Nature
New neurons for life? Old people can still make fresh brain cells, study finds, Science
More Evidence that Humans Do Appear to Create New Neurons in Old Age, The Scientist
Our brains may be able to make new neurons throughout adulthood, New Scientist
Old brains still make neurons, study finds, offering a possible way to protect against Alzheimer’s, STAT
Original Journal Article: Adult hippocampal neurogenesis is abundant in neurologically healthy subjects and drops sharply in patients with Alzheimer’s disease, Nature Medicine
Image Credit: Llorens-Martín lab, Nature Medicine paper
Originally published at sitn.hms.harvard.edu on April 3, 2019.