A study found that when mice are born there is a reduction of a chemical in the brain called serotonin which triggers the "sensory maps" responsible for translating perceptions such as touch into understanding.
The study shows that the act of birth triggers these developments in the brain which prepare the newborn for life outside of the womb, a Cell Press news release reported.
"Our results clearly demonstrate that birth has active roles in brain formation and maturation," senior study author Hiroshi Kawasaki of Kanazawa University in Japan, said. "We found that birth regulates neuronal circuit formation not only in the somatosensory system but also in the visual system. Therefore, it seems reasonable to speculate that birth actually plays a wider role in various brain regions."
Almost all creatures, including mice and humans, possess these brain maps that process all kinds of sensory information. For example, a part of a mouse's brain called the barrel cortex contains a map that processes information gathered by the rodent's whiskers.
"Neighboring columns of neurons responding to stimulation of adjacent whiskers. Although previous studies have shown that the neurotransmitter serotonin influences the development of sensory maps, its specific role during normal development has not been clear until now," the news release stated.
The study found that the birth of the mice pups triggers the decrease of serotonin, which in turn triggers the formations of neural circuits in the barrel cortex and in the lateral geniculate nucleus (responsible for interpreting visual information).
The team noticed that when the newborns were given drugs that induced early birth or decreased serotonin, the maps developed even more quickly. The neural circuits in the barrel cortex did not form when the pups were given drugs that increased serotonin.
Serotonin is also involved with mental disorders, which could mean that an abnormal birth could put one more at risk, and some of the conditions could be treated with drugs early-on.
"Uncovering the entire picture of the downstream signaling pathways of birth may lead to the development of new therapeutic methods to control the risk of psychiatric diseases induced by abnormal birth," Kawasaki said.
