Their findings, reported this week in the online version of the Proceedings of the National Academy of Sciences, challenge the notion that the time it takes for neurogenesis is the reason anti-depressant medications are not fully effective until three to five weeks after treatment begins.
The dentate gyrus of the brain's hippocampus is known to be where new neurons still form in adult mammals, and this region is thought to play a significant role in learning and memory, cognitive change with aging, depression and schizophrenia, and other brain processes, said Judy Cameron, Ph.D., professor, Department of Psychiatry, University of Pittsburgh School of Medicine, and senior scientist, Oregon National Primate Research Center, Oregon Health and Science University.
"Expanding our knowledge beyond rodent models to understand how neurons mature in non-human primates will give us more insight into what happens in the human brain," she said. "In rodents, neuronal maturation happens in four weeks, which is considerably different than what we have found in our monkey studies."
Dr. Cameron, co-senior scientist William T. Greenough, Ph.D., of the University of Illinois, and the team gave adult monkeys injections of an agent called BrdU, which gets incorporated into replicating DNA and thus serves as an indicator of new neuron formation. At different time points after the injections, they examined the brain tissue to look for markers of stages of maturation in tiny neurons called granule cells.
Six weeks after an injection, 84 percent of the new cells still bore markers of immaturity and were immature in shape; in a rodent, all of the cells would have matured by this time. Only a third of the monkey granule cells had markers of maturity up to 28 weeks after BrdU injections.
That means the majority of new granule cells will not reach maturity until more than six months have passed, Dr. Greenough and colleagues said. Also, because the human brain is larger than the monkey brain and takes longer to develop, maturation of adult human neurons would likely be further lengthened.
The longer period of new granule cell maturation in primates argues against the hypothesis, based on rodent models, that the onset of effectiveness of antidepressant medications at three to five weeks is related to neurogenesis and maturation of these cells.
The research team included Shawn J. Kohler and Gregory B. Stanton, Ph.D., of the University of Illinois; and Nancy I. Williams, Sc.D., of Pennsylvania State University. The study was funded by the National Institutes of Health, the Spastic Paralysis and Allied Diseases of the Central Nervous System Foundation, and the Retirement Research Foundation.
About the University of Pittsburgh School of Medicine
As one of the nation's leading academic centers for biomedical research, the University of Pittsburgh School of Medicine integrates advanced technology with basic science across a broad range of disciplines in a continuous quest to harness the power of new knowledge and improve the human condition. Driven mainly by the School of Medicine and its affiliates, Pitt has ranked among the top 10 recipients of funding from the National Institutes of Health since 1997.
Likewise, the School of Medicine is equally committed to advancing the quality and strength of its medical and graduate education programs, for which it is recognized as an innovative leader, and to training highly skilled, compassionate clinicians and creative scientists well-equipped to engage in world-class research. The School of Medicine is the academic partner of UPMC, which has collaborated with the University to raise the standard of medical excellence in Pittsburgh and to position health care as a driving force behind the region's economy. For more information about the School of Medicine, see www.medschool.pitt.edu.
Bacteria as pacemaker for the intestine
22.11.2017 | Christian-Albrechts-Universität zu Kiel
Researchers identify how bacterium survives in oxygen-poor environments
22.11.2017 | Columbia University
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Business and Finance
22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy