Welcome to The Visible Embryo

 

 

Home-- -History-- -Bibliography- -Pregnancy Timeline- --Prescription Drugs in Pregnancy- -- Pregnancy Calculator- --Female Reproductive System- -Contact
 

Welcome to The Visible Embryo, a comprehensive educational resource on human development from conception to birth.

The Visible Embryo provides visual references for changes in fetal development throughout pregnancy and can be navigated via fetal development or maternal changes.

The National Institutes of Child Health and Human Development awarded Phase I and Phase II Small Business Innovative Research Grants to develop The Visible Embryo. Initally designed to evaluate the internet as a teaching tool for first year medical students, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than one million visitors each month.

Today, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than 1 million visitors each month. The field of early embryology has grown to include the identification of the stem cell as not only critical to organogenesis in the embryo, but equally critical to organ function and repair in the adult human. The identification and understanding of genetic malfunction, inflammatory responses, and the progression in chronic disease, begins with a grounding in primary cellular and systemic functions manifested in the study of the early embryo.

WHO International Clinical Trials Registry Platform


The World Health Organization (WHO) has created a new Web site to help researchers, doctors and
patients obtain reliable information on high-quality clinical trials. Now you can go to one website and search all registers to identify clinical trial research underway around the world!



Home

History

Bibliography

Pregnancy Timeline

Prescription Drug Effects on Pregnancy

Pregnancy Calculator

Female Reproductive System

Contact The Visible Embryo

News Alerts Archive

Disclaimer: The Visible Embryo web site is provided for your general information only. The information contained on this site should not be treated as a substitute for medical, legal or other professional advice. Neither is The Visible Embryo responsible or liable for the contents of any websites of third parties which are listed on this site.
Content protected under a Creative Commons License.

No dirivative works may be made or used for commercial purposes.

 

Pregnancy Timeline by SemestersFetal liver is producing blood cellsHead may position into pelvisBrain convolutions beginFull TermWhite fat begins to be madeWhite fat begins to be madeHead may position into pelvisImmune system beginningImmune system beginningPeriod of rapid brain growthBrain convolutions beginLungs begin to produce surfactantSensory brain waves begin to activateSensory brain waves begin to activateInner Ear Bones HardenBone marrow starts making blood cellsBone marrow starts making blood cellsBrown fat surrounds lymphatic systemFetal sexual organs visibleFinger and toe prints appearFinger and toe prints appearHeartbeat can be detectedHeartbeat can be detectedBasic Brain Structure in PlaceThe Appearance of SomitesFirst Detectable Brain WavesA Four Chambered HeartBeginning Cerebral HemispheresFemale Reproductive SystemEnd of Embryonic PeriodEnd of Embryonic PeriodFirst Thin Layer of Skin AppearsThird TrimesterSecond TrimesterFirst TrimesterFertilizationDevelopmental Timeline
CLICK ON weeks 0 - 40 and follow along every 2 weeks of fetal development
Google Search artcles published since 2007
 
 

Home | Pregnancy Timeline | News Alerts |News Archive Oct 15, 2013

 

In mice transfected with the voltage sensor (left), deflection of a whisker leads
to fluorescence in the corresponding region of barrel cortex (right).

Image credit: Thomas Knöpfel, RIKEN Brain Science Institute










WHO Child Growth Charts

 

 

 

Birth gets the brain ready for the world

Neurons must be arranged in precise, well-organized maps crucial to translating perception into understanding. Birth triggers a drop in seratonin levels that stimulates the formation of neural circuits in both visual and somatosensory systems.

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 birth has active roles in brain 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 mice to humans have brain maps that represent various types of sensory information. 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 serotonin 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 neural circuits 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 development of new therapeutic methods to control the risk of psychiatric diseases induced by abnormal birth," Kawasaki says.

Abstract Highlights
The birth of pups regulates initiation of barrel formation in cerebral cortex
The birth of pups leads to the reduction of 5-HT
5-HT reduction is necessary and sufficient for birth’s effect on barrel formation
Birth and 5-HT also regulate eye-specific segregation in the visual thalamus
Summary

Although the mechanisms underlying the spatial pattern formation of sensory maps have been extensively investigated, those triggering sensory map formation during development are largely unknown. Here we show that the birth of pups instructively and selectively regulates the initiation of barrel formation in the somatosensory cortex by reducing serotonin concentration. We found that preterm birth accelerated barrel formation, whereas it did not affect either barreloid formation or barrel structural plasticity. We also found that serotonin was selectively reduced soon after birth and that the reduction of serotonin was triggered by birth. The reduction of serotonin was necessary and sufficient for the effect of birth on barrel formation. Interestingly, the regulatory mechanisms described here were also found to regulate eye-specific segregation in the visual system, suggesting that they are utilized in various brain regions. Our results shed light on roles of birth and serotonin in sensory map formation.

Developmental Cell, Toda et al.: "Birth regulates the initiation of sensory map formation through serotonin signaling."

Original press releas:http://www.eurekalert.org/pub_releases/2013-10/cp-bgt100813.php