Our generation might be notorious for not listening to its elders, but our brain cells never stopped listening to theirs. Scientists at Yale University recently discovered that newly synthesized neurons in our brains “listen” to older neurons before they send out their own impulses. In other words, brain cells listen before they speak.
Past studies have showed that the regions of the brain produce new neurons and incorporate them into the existing brain circuitry. The mechanism behind this function of activity was not known until the Yale School of Medicine made this most recent discovery.
A team of researchers led by Charles Greer, professor of neurosurgery and neurobiology at Yale, discovered that new brain cells take time to mature. New synaptic connections in a brain cell are not made until 21 days after the cell’s birth. In the meantime, the cell receives signals from others, ensuring that these new brain cells do not disturb ongoing signals in the brain.
The team studied the olfactory bulb, a part of the brain associated with the perception of odours, in order to find the mechanism by which new brain cells are incorporated into existing brain circuitry. They found that new neurons receive signals from parts of the brain for up to 10 days. During this period, these neurons do not generate their own signals. It takes these neurons six to eight weeks to mature, during which period they are monitored by signals from other brain cells.
This finding has important implications for the use of stem cells to cure neurodegenerative diseases. This mechanism implies that newly synthesized neurons from stem cells will not interfere with ongoing brain signaling until the stem cells mature. Said Greer: “If we want to use stem cells to replace neurons lost to injury or disease, we must ensure that they do not fire inappropriately, which could cause seizures or cognitive dysfunction.”
