Researchers have discovered that neurons in the paralaminar nucleus (PL) of the amygdala stay in an immature, prenatal developmental state throughout childhood. Furthermore, most of these cells mature rapidly during adolescence, suggesting a key role in the brain's emotional development. However, some stay immature throughout life, suggesting new theories on how the brain keeps its emotional responses flexible throughout life.
Using single nuclei RNA sequencing, researchers identified the transcriptional profile of immature excitatory neurons in the human amygdala between 4 and 15 years.
They found that immature neurons continue to be present in the PL in adolescents and adults, even in individuals 77-years-old. However, the number of dividing (Ki-67+) cells declined rapidly in the PL and neighbouring regions within the first year of life.
The authors concluded that the human PL contains excitatory neurons that remain immature for decades, and this is a possible substrate for persistent plasticity at the interface of the hippocampus and amygdala.
They said the manner in which this process is regulated and the types of genetic and environmental influences that can affect it are “exciting directions for future investigation”.
The research is published in the journal Nature Communications.