Birth gets the brain ready to sense the world

October 14, 2013

Neurons that process sensory information such as touch and vision are arranged in precise, well-characterized maps that are crucial for translating perception into understanding. A study published by Cell Press on October 14 in the journal Developmental Cell reveals that the actual act of birth in mice causes a reduction in a brain chemical called serotonin in the newborn mice, triggering sensory maps to form. The findings shed light on the key role of a dramatic environmental event in the development of neural circuits and reveal that birth itself is one of the triggers that prepares the newborn for survival outside the womb.

"Our results clearly demonstrate that has active roles in formation and maturation," says senior study author Hiroshi Kawasaki of Kanazawa University in Japan. "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."

Mammals ranging from to humans have brain maps that represent various types of . In a region of the rodent brain known as the barrel cortex, neurons that process tactile information from whiskers are arranged in a map corresponding to the spatial pattern of whiskers on the snout, with neighboring columns of neurons responding to stimulation of adjacent whiskers. Although previous studies have shown that the neurotransmitter influences the development of sensory maps, its specific role during normal development has not been clear until now.

In this new study, Kawasaki and his team find that the birth of mouse pups leads to a drop in serotonin levels in the newborn's brain, triggering the formation of in the barrel cortex and in the lateral geniculate nucleus (LGN), a brain region that processes visual information. When mice were treated with drugs that either induced preterm birth or decreased serotonin signaling, neural circuits in the barrel cortex as well as in the LGN formed more quickly. Conversely, neural circuits in the barrel cortex failed to form when the mice were treated with a drug that increased serotonin signaling, suggesting that a reduction in levels of this neurotransmitter is crucial for sensory map formation.

Because serotonin also plays a key role in mental disorders, it is possible that abnormalities in birth processes and the effects on subsequent serotonin signaling and brain development could increase the risk of psychiatric diseases. "Uncovering the entire picture of the downstream signaling pathways of birth may lead to the of new therapeutic methods to control the risk of psychiatric diseases induced by abnormal birth," Kawasaki says.

More information: Developmental Cell, Toda et al.: "Birth regulates the initiation of sensory map formation through serotonin signaling." dx.doi.org/10.1016/j.devcel.2013.09.002

Related Stories

Timing is key in the proper wiring of the brain: study

December 19, 2011

(Medical Xpress) -- After birth, the developing brain is largely shaped by experiences in the environment. However, neurobiologists at Yale and elsewhere have also shown that for many functions the successful wiring of neural ...

Serotonin mediates exercise-induced generation of new neurons

May 13, 2013

Mice that exercise in running wheels exhibit increased neurogenesis in the brain. Crucial to this process is serotonin signaling. These are the findings of a study by researchers at the Max Delbrück Center Berlin-Buch. Surprisingly, ...

Getting a grip on sleep

May 14, 2013

All mammals sleep, as do birds and some insects. However, how this basic function is regulated by the brain remains unclear. According to a new study by researchers from the RIKEN Brain Science Institute, a brain region called ...

Problem-solving governs how we process sensory stimuli

June 25, 2013

Various areas of the brain process our sensory experiences. How the areas of the cerebral cortex communicate with each other and process sensory information has long puzzled neu-roscientists. Exploring the sense of touch ...

Recommended for you

Improved memory thanks to irregular sleep-wake patterns

July 31, 2015

If you've had a good night's sleep, you are mentally more alert and your memory works more reliably. During sleep, a part of our forebrain called the prefrontal cortex remains active. It ensures that memories and learned ...

Take a trip through the brain (w/ Video)

July 30, 2015

A new imaging tool developed by Boston scientists could do for the brain what the telescope did for space exploration. In the first demonstration of how the technology works, published July 30 in the journal Cell, the researchers ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

beleg
not rated yet Nov 06, 2013
An entire picture of prenatal downstream signaling pathways of gestation will contribute as much as the entire picture downstream signaling pathways of birth.
Prenatal therapeutic methods will improve from this as well.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.