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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 ' million visitors each month.


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!



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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 weeks 0 - 40 and follow fetal growth
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April 29, 2011--------News Archive

Catching Autism At The 1-year Well-Baby Check-Up
A novel strategy developed by autism researchers at the University of California, San Diego, shows promise as a simple way to detect cases of Autism Syndrome.

A New Wrinkle In The Genetic Code
Long ago a mouse was created that is just now teaching us that mutations in the proteins produced from ribosomes can lead to unexpected birth defects.


April 28, 2011--------News Archive

Tired Neurons Nod Off in Sleep-Deprived Rats
The more rats are sleep-deprived, the more neurons take catnaps. Though the animals are awake and active, neurons in the cortex, are briefly falling asleep.

Obese Adolescents Lacking Vitamin D
Vitamin D status is significantly associated with muscle power/force; a deficiency may interfere with the obese adolescent's ability to increase physical activity.


April 27, 2011--------News Archive

Men and Women Respond Differently to PTSD
Men and women had starkly different immune system responses to chronic post-traumatic stress disorder. Men show no response, women show a strong one.

Motor Protein May Offer Promise In Ovarian Cancer
A regulatory motor protein can block ovarian tumor growth, leading to cancer cell death and new therapies to treat the disease.


April 26, 2011--------News Archive

Protein Levels Could Signal Childhood Diabetes
Decreasing blood levels of a protein that helps control inflammation may be a red flag that could help children avoid type 1 diabetes.

Best Treatment For Gestational Tumors
A clinical trial has sifted out the most effective chemotherapy regimen for quick-growing but highly curable cancers arising from the placentas of pregnant women.


April 25, 2011--------News Archive

Frog Embryos Teach Us About Heart Development
Thanks to new research at the University of Pennsylvania, there is new insight into the processes that regulate the formation of the heart.

Brain Cells Offer Insight on How Cancer Spreads
The mechanism regulating embryonic development in plants displays similarities to a signalling pathway in embryonic stem cells in mammals.

WHO Child Growth Charts

Rats with objects introduced into their cages to keep them awake. Source: Giulio Tononi, M.D., Ph.D., University of Wisconsin-Madison

A new study in rats is shedding light on how sleep-deprived lifestyles might impair functioning without people realizing it.

The more rats are sleep-deprived, the more some of their neurons take catnaps - with consequent declines in task performance. Even though the animals are awake and active, brainwave measures reveal that scattered groups of neurons in the thinking part of their brain, or cortex, are briefly falling asleep, scientists funded by the National Institutes of Health have discovered.

"Such tired neurons in an awake brain may be responsible for the attention lapses, poor judgment, mistake-proneness and irritability that we experience when we haven't had enough sleep, yet don't feel particularly sleepy," explained Giulio Tononi, M.D., Ph.D., of the University of Wisconsin-Madison.

"Strikingly, in the sleep-deprived brain, subsets of neurons go offline in one cortex area but not in another — or even in one part of an area and not in another."

Tononi and colleagues report their findings online in the April 28, 2011 issue of the journal Nature. Their study was funded in part by the NIH's National Institute of Mental health and a NIH Director's Pioneer Award, supported through the Common Fund, and administered by NIMH and the National Institute on Neurological Disorders and Stroke.

Previous studies had hinted at such local snoozing with prolonged wakefulness. Yet little was known about how underlying neuronal activity might be changing.

To learn more, the researchers tracked electrical activity at multiple sites in the cortex as they kept rats awake for several hours. They put novel objects into their cages - colorful balls, boxes, tubes and odorous nesting material from other rats. The sleepier the rats got, more subsets of cortex neurons switched off, seemingly randomly, in various localities. These tired neurons' electrical profiles resembled those of neurons throughout the cortex during NREM or slow wave sleep. Yet, the rats' overall EEG, a measure of brain electrical activity at the scalp, confirmed that they were awake, as did their behavior. So neuronal tiredness differs from more overt "microsleep" - 3-15-second lapses with eyes closing and sleep-like EEG - that is sometimes experienced with prolonged wakefulness. It is more analogous to local lapses seen in some forms of epilepsy, suggest the researchers.

However subtle, having tired neurons did interfere with task performance. If neurons switched off in the motor cortex within a split second before a rat tried to reach for a sugar pellet, it decreased its likelihood of success by 37.5 percent. And the overall number of such misses increased significantly with prolonged wakefulness. This suggests that tired neurons, and accompanying increases in slow wave activity, might help to account for the impaired performance of sleep-deprived people who may seem behaviorally and subjectively awake.

Subsets of neurons going offline with longer wakefulness is, in many ways, the mirror image of progressive changes that occur during recovery sleep following a period of sleep deprivation. Tononi suggests that both serve to maintain equilibrium - part of the compensatory mechanisms that regulate sleep need. Just as sleep deprivation produces a brain-wide state of instability, it may also trigger local instability in the cortex, possibly by depleting levels of brain chemical messengers. So, tired neurons might nod off as part of an energy-saving or restorative process for overloaded neuronal connections.

"Research suggests that sleep deprivation during adolescence may have adverse emotional and cognitive consequences that could affect brain development," noted NIMH Director Thomas R. Insel, M.D. "The broader line of studies to which this belongs, are, in part, considering changes in sleep patterns of the developing brain as a potential index to the health of neural connections that can begin to go awry during the critical transition from childhood to the teen years."

The mission of the NIMH is to transform the understanding and treatment of mental illnesses through basic and clinical research, paving the way for prevention, recovery and cure. For more information, visit the NIMH website.

NINDS, a component of the National Institutes of Health (NIH) within the U.S. Department of Health and Human Services, is the nation’s primary supporter of basic, translational, and clinical research on the brain and nervous system. NINDS aims to reduce the burden of neurological disease among all Americans. Go to www.ninds.nih.gov for more information.

The National Institutes of Health (NIH), is the nation's medical research agency and includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit the NIH website.

Local sleep in awake rats. Vyazovskiy VV, Olcese U, Hanlon EC, Nir Y, Cirelli C, Tononi G. Nature. 2011 April 28.

Original Article: http://www.nimh.nih.gov/science-news/2011/tired-neurons-caught-nodding-off-in-sleep-deprived-rats.shtml