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Nuclear bomb tests reveal brain regeneration in humans
Nuclear bomb tests carried out during the cold war have had an unexpected benefit.
A radioactive carbon isotope expelled by the blasts has been used to date the age of adult human brain cells, providing the first definitive evidence that wegenerate new brain cells throughout our lives. The study also provides the first model of the dynamics of the process, showing that the regeneration of neurons does not drop off with age as sharply as expected.
In mammals, most types of brain cell are created at or soon after birth and are never renewed. But studies in rodents and monkeys have shown that in two regions new neurons continue to be created even in adulthood – the hippocampus, which is involved in learning and the formation of new memories, and the olfactory bulb, which processes smell.
However, there has been some controversy over whether the same is true for humans. Fifteen years ago a study found evidence for such neurogenesis in adults up to the age of 72 (Nature Medicine, doi.org/b7hjfz), but the research relied on a chemical called bromodeoxyuridine (BrdU) to label neurons. BrdU was used at the time to track the spread of tumours in people with cancer, but it was banned shortly after and so the study was never repeated, leading some researchers to question the results.
Another study on London taxi drivers suggested that the hippocampus grows with increasing knowledge of the city but this, too, has been controversial.
Radioactive growth
The new study settles the debate. "The existence of adult hippocampal neurogenesis in humans is not arguable this time," says Sandrine Thuret at King's College London, who was not involved in the work.
Instead of chemical labelling, Jonas Frisén at the Karolinska Institute in Stockholm, Sweden, and colleagues used a by-product of the above-ground nuclear bomb tests carried out by the US, UK and Soviet Union between 1945 and 1963. As a result of these detonations, atmospheric levels of the radioactive isotope carbon-14 increased dramatically during this period. It has decreased steadily since.
Carbon-14 enters the food chain and eventually finds its way into our cells, which integrate carbon-14 atoms into their DNA when a parent cell splits into two new daughter cells. The amount of carbon-14 in the atmosphere is therefore mirrored in the cells at the time they are born.
By analysing brain tissue using mass spectrometry equipment, the team was able to measure the number of carbon-14 atoms trapped in different populations of cells in different brain regions.
They could then compare this figure to known data for atmospheric levels of carbon-14 to date the birth of a cell in different people to within about a year. The level of carbon-14 is higher in older cells grown closer to the peak of nuclear bomb testing than in cells born more recently.
Frisén's team previously used this method to show that humans are the only known mammal in which neurogenesis does not occur in the adult olfactory bulb, since the cells in this brain region were the same age.
Forever young
But looking at the hippocampus in 55 post-mortem brains aged between 19 and 92, the team has now found that a subset of neurons in an area of the hippocampus called the dentate gyrus are indeed created throughout adulthood. In effect, a small population of our brain cells remains permanently young, renewing itself continually. By modelling the process, the team estimated that we generate around 1400 new neurons every day. "Everyone working on adult hippocampal neurogenesis is excited about this work," says Thuret.
The team was surprised that the ability to create new neurons appears to stay with humans longer than it does in mice. "In mice the decline is pretty dramatic," says Frisén. But instead of the 10-fold decrease between young and middle-aged mice, the team found only a four-fold decrease in humans, he says.
But the newborn brain cells in humans do not appear to live long. In rodents, the hippocampus gradually gets bigger as new cells are added. "In mice, there is a net increase," says Thuret. But this is not seen in humans – in fact, our hippocampus slowly shrinks. "There are more dying than being born," she says.
The reason for this turnover remains unknown. Many studies in mice show that young neurons are necessary for forming new memories. But this has not been tested in humans.
Source: http://www.newscientist.com/article/dn23665-nuclear-bomb-tests-reveal-brain-regeneration-in-humans.html#.Uee0dtIqx2A
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Founded by Russian entrepreneur Dmitry Itskov in February 2011 with the participation of leading Russian specialists in the field of neural interfaces, robotics, artificial organs and systems.
The main goals of the 2045 Initiative: the creation and realization of a new strategy for the development of humanity which meets global civilization challenges; the creation of optimale conditions promoting the spiritual enlightenment of humanity; and the realization of a new futuristic reality based on 5 principles: high spirituality, high culture, high ethics, high science and high technologies.
The main science mega-project of the 2045 Initiative aims to create technologies enabling the transfer of a individual’s personality to a more advanced non-biological carrier, and extending life, including to the point of immortality. We devote particular attention to enabling the fullest possible dialogue between the world’s major spiritual traditions, science and society.
A large-scale transformation of humanity, comparable to some of the major spiritual and sci-tech revolutions in history, will require a new strategy. We believe this to be necessary to overcome existing crises, which threaten our planetary habitat and the continued existence of humanity as a species. With the 2045 Initiative, we hope to realize a new strategy for humanity's development, and in so doing, create a more productive, fulfilling, and satisfying future.
The "2045" team is working towards creating an international research center where leading scientists will be engaged in research and development in the fields of anthropomorphic robotics, living systems modeling and brain and consciousness modeling with the goal of transferring one’s individual consciousness to an artificial carrier and achieving cybernetic immortality.
An annual congress "The Global Future 2045" is organized by the Initiative to give platform for discussing mankind's evolutionary strategy based on technologies of cybernetic immortality as well as the possible impact of such technologies on global society, politics and economies of the future.
Future prospects of "2045" Initiative for society
2015-2020
The emergence and widespread use of affordable android "avatars" controlled by a "brain-computer" interface. Coupled with related technologies “avatars’ will give people a number of new features: ability to work in dangerous environments, perform rescue operations, travel in extreme situations etc.
Avatar components will be used in medicine for the rehabilitation of fully or partially disabled patients giving them prosthetic limbs or recover lost senses.
2020-2025
Creation of an autonomous life-support system for the human brain linked to a robot, ‘avatar’, will save people whose body is completely worn out or irreversibly damaged. Any patient with an intact brain will be able to return to a fully functioning bodily life. Such technologies will greatly enlarge the possibility of hybrid bio-electronic devices, thus creating a new IT revolution and will make all kinds of superimpositions of electronic and biological systems possible.
2030-2035
Creation of a computer model of the brain and human consciousness with the subsequent development of means to transfer individual consciousness onto an artificial carrier. This development will profoundly change the world, it will not only give everyone the possibility of cybernetic immortality but will also create a friendly artificial intelligence, expand human capabilities and provide opportunities for ordinary people to restore or modify their own brain multiple times. The final result at this stage can be a real revolution in the understanding of human nature that will completely change the human and technical prospects for humanity.
2045
This is the time when substance-independent minds will receive new bodies with capacities far exceeding those of ordinary humans. A new era for humanity will arrive! Changes will occur in all spheres of human activity – energy generation, transportation, politics, medicine, psychology, sciences, and so on.
Today it is hard to imagine a future when bodies consisting of nanorobots will become affordable and capable of taking any form. It is also hard to imagine body holograms featuring controlled matter. One thing is clear however: humanity, for the first time in its history, will make a fully managed evolutionary transition and eventually become a new species. Moreover, prerequisites for a large-scale expansion into outer space will be created as well.
Key elements of the project in the future
• International social movement
• social network immortal.me
• charitable foundation "Global Future 2045" (Foundation 2045)
• scientific research centre "Immortality"
• business incubator
• University of "Immortality"
• annual award for contribution to the realization of the project of "Immortality”.
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