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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.

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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!





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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
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Home | Pregnancy Timeline | News Alerts |News Archive Dec 23, 2014

Carnegie Stage 15 of human development Basic Brain Structure in Place

Errors in development of the dorsolateral prefrontal cortex have been linked to Autism.

 






 

 

Cracking the code of brain development

Researchers find a new approach to identifying the biological roots of developmental disorders from shizophrenia to autism.

With a unique approach, researchers at the Lieber Institute for Brain Development (LIBD) have measured the effect of previously unidentified gene anomalies to determine how the human brain develops. Their results offer a novel technique for identifying biological markers in brain development associated with risk for neurodevelopmental disorders such as schizophrenia and autism spectrum disorder (ASD).

The work is published in Nature Neuroscience.

Using state-of-the-art sequencing technology, they examined postmortem brain samples from their vast collection, identifying many thousands of differences in gene expression — or the turning ON of the gene — within differential expression regions or DERs, across all of life's stages. These DERs are located in the dorsolateral prefrontal cortex (DLPFC) of the brain.

Brains from six distinct life stages were examined: 1) fetal 2) infant 3) child 4) teen 5) adult and 6) late life. Researchers focused on the DLPFC brain region because of its known association with schizophrenia and ASD. The team used the sophisticated "derfinder" statistical approach to identify regions.


"By searching the entire genome for association with the 'derfinder' technique, we were able to identify many segments of the genome that were previously thought to not play an active role in brain development,"

Andrew E. Jaffe PhD, Investigator, LIBD and lead author.


Following an analysis of 72 human brain samples, researchers accessed open-source databases to identify DERs and then map them onto the human genome. With this data, they were able to locate expression in 16 different brain regions of the developing mouse cortex, and then in human tissue samples and stem cells.

They found that genes containing DERs most highly expressed from infancy through adulthood were highly associated with important brain signaling and communication mechanisms. The vast majority of DERs were found to be crucial in the maturation of neurons during fetal development, giving new evidence to how neurodevelopmental disorders may first begin.


"We find that the transition from fetal to postnatal life is the primary driver of differential expression, and the differences appear to represent a 'signature' found in cells from the earliest stages of development."

Andrew E. Jaffe PhD.


Team members found the patterns to be similarly expressed across the 16 brain regions, suggesting genes containing these DERs function as developmental ON switches for the brain, regardless of where they are located.

There is significant overlap between "signature genes" of cells in early brain development and in brain regions showing genetic risk for schizophrenia as well as in genes previously associated with ASD and Intellectual Disability, all regions identified in the latest international genome-wide association study (GWAS). Significantly, DERs which are most expressed in late life stages overlapped other regions of genetic risk for disorders such as Alzheimer's disease and Parkinson's disease.


"By linking developmental brain disorders like schizophrenia and autism to specific molecular signatures in early brain development, we are much closer to finding new treatments based on how a brain first becomes ill rather than only on how it behaves ill."

Daniel R. Weinberger MD, Director and CEO of LIBD.


The LIBD team believes that many of the DERs important in brain development — as well as developmental "signature genes" — contain anomalies not measurable with previous technology. This suggests that the transcriptome which is supposed to reflect genes actively expressed (or ON) at any given moment in the human genome, is incomplete.

All of the team's data is openly accessible for further analyses in the new Track Hub of the UCSC Genome Browser "LIBD Human DLPFC Development" and through databases maintained by the National Center for Biotechnology Information.

Abstract
Transcriptome analysis of human brain provides fundamental insight into development and disease, but it largely relies on existing annotation. We sequenced transcriptomes of 72 prefrontal cortex samples across six life stages and identified 50,650 differentially expression regions (DERs) associated with developmental and aging, agnostic of annotation. While many DERs annotated to non-exonic sequence (41.1%), most were similarly regulated in cytosolic mRNA extracted from independent samples. The DERs were developmentally conserved across 16 brain regions and in the developing mouse cortex, and were expressed in diverse cell and tissue types. The DERs were further enriched for active chromatin marks and clinical risk for neurodevelopmental disorders such as schizophrenia. Lastly, we demonstrate quantitatively that these DERs associate with a changing neuronal phenotype related to differentiation and maturation. These data show conserved molecular signatures of transcriptional dynamics across brain development, have potential clinical relevance and highlight the incomplete annotation of the human brain transcriptome.

Paper Authors: Jaffe A.E., Shin J., Collado-Torres L., Leek J.T., Tao R., Li C., Gao Y., Jia Y., Maher B.J., Hyde T.M., Kleinman J.E., and Weinberger D.R. Developmental regulation of human cortex transcription and its clinical relevance at single base resolution.Nature Neuroscience, 2014, Dec 15. doi:10.1038/nn.3898.


About LIBD
The mission of the Lieber Institute for Brain Development is to translate the understanding of basic genetic and molecular mechanisms of schizophrenia and related developmental brain disorders into clinical advances that change the lives of affected individuals. LIBD is an independent, not-for-profit 501(c)(3) organization and a Maryland tax-exempt medical research institution affiliated with the Johns Hopkins University School of Medicine.


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