If the brain is capable of regenerating neurons in the amygdala, then that's potentially one way of fighting back against these mental health issues, according to the team from the University of Queensland in Australia.
"While it was previously known that new neurons are produced in the adult brain, excitingly this is the first time that new cells have been discovered in the amygdala," says one of the team, Pankaj Sah from the Queensland Brain Institute.
"Our discovery has enormous implications for understanding the amygdala's role in regulating fear and fearful memories."
Before now, neurogenesis – the process of producing new neurons – had only been spotted in human adults in the hippocampus, the part of the brain that handles long-term memory and also deals with emotional responses, and the striatum.
Adult neurogenesis was first recognised in the 1960s, but was more widely accepted in the 1990s, thanks in part to the discovery of stem cells in adult mice brains – cells that can divide and develop into other types of cells.
That discovery was made by another team from the Queensland Brain Institute, and since then, scientists have confirmed the same process happens in humans.
Now it looks like it's happening elsewhere too: based on new studies of mice, the researchers found evidence for the same stem cells in the amygdala, cells that could turn into genuine, fully functioning neurons. Now the task is to find the same results in humans.
Right now it's not clear what those new neurons do, or how the brain uses them, but their location is interesting and worthy of further study.
There's so much we still don't know about the brain, though its secrets are slowly being unlocked. As far as neurogenesis goes, for example, we know that a session on the booze slows down the process, though giving up the drink reverses the process.
Meanwhile, a study published in July found that implanting stem cells into the brain can help to extend the lifespan of mice, and it's possible that a similar approach here could also have a positive effect.
"Finding ways of stimulating the production of new brain cells in the amygdala could give us new avenues for treating disorders of fear processing, which include anxiety, PTSD and depression," says one of the team, Dhanisha Jhaveri.
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