To remember conversations, keep making new brain cells
Why do adults make new brain cells? A new study published in Cell Stem Cell provides the first cellular evidence that making new brain cells in adults supports verbal learning and memory, which enables people to have conversations and to remember what they hear. This discovery could point to new approaches to restore cognitive function.
The study relied on brain tissue from patients with drug-resistant cases of mesial temporal lobe epilepsy (MTLE), which involves seizures as well as accelerated cognitive decline.
“Treating patients with epilepsy allows us to investigate the purpose of generating new neurons in our brains. We observe that one of reasons is to learn from the conversations we have” said co-corresponding author.
“These findings are clearly important for all people who suffer from learning and cognitive decline, but they are also specifically relevant to the epilepsy patients who participated in the research,” added another co-corresponding author.
In the study, the authors investigated how the process of making new brain cells—called neurogenesis—affects different types of cognitive decline during the progression of MTLE.
The researchers found that MTLE patients experience cognitive decline in many areas including verbal learning and memory, intelligence, and visuospatial skills. For verbal learning and memory, as well as for intelligence, patients undergo a dramatic decline during the first 20 years of seizures. During those same two decades, neurogenesis slows to the point where immature brain cells became nearly undetectable.
Based on these observations, the scientists searched for links between the number of immature brain cells and the major areas of MTLE-related cognitive decline. They found the strongest association occurs between the declining number of immature brain cells and verbal learning and memory.
This is a surprising finding because neurogenesis levels in rodents and other lab animals contribute to a different type of learning and memory using visuospatial skills. The role of neurogenesis in verbal learning and memory highlights the value of studying human brain tissue.
“Our study provides the first cellular evidence of how neurogenesis contributes to human cognition—in this case, verbal learning and memory,” said the author. “This work opens a gateway for future studies exploring ways to improve verbal learning and memory by boosting neurogenesis, possibly through exercise or therapeutic drugs. Those approaches could help not only patients with MTLE, Alzheimer’s disease and dementia, but also all of us with aging brains.”
https://www.cell.com/cell-stem-cell/fulltext/S1934-5909(24)00401-6
