Hiroshi Kawasaki of Kanazawa University in Japan and colleagues are the first to discover the role of the birthing process in the development of neural circuits in mammal brains according to their report in the Oct. 14, 2013, edition of the journal Developmental Cell.
The birth process itself was found to reduce serotonin levels in mice. The reduction in serotonin levels turned on neural circuitry that is responsible for tactile information sensing and visual sensing.
Serotonin level reduction during birth was found to initiate a mouse baby’s tactile feeling for the position of each whisker and the relative position of the other whiskers in the barrel cortex region of the mouse brain. The lateral geniculate nucleus brain region that processes visual information was also awakened by the serotonin drop during birth.
Mice that were forced into early birth demonstrated the same initiation of neural circuitry through the reduction of serotonin levels just like mice born at term. Mice that were exposed to excess levels of serotonin at birth did not initiate the whisker feeling circuitry or the visual circuitry.
The researchers propose that a host of senses and brain circuitry is cranked up in humans and other mammals by the reduction of serotonin during the birth process.
The research may have applications in birth defect prevention and mental illness treatment.