/ News
How attention helps you remember
A new study from MIT neuroscientists sheds light on a neural circuit that makes us likelier to remember what we’re seeing when our brains are in a more attentive state.
The team of neuroscientists found that this circuit depends on a type of brain cell long thought to play a supporting role, at most, in neural processing. When the brain is attentive, those cells, called astrocytes, relay messages alerting neurons of the visual cortex that they should respond strongly to whatever visual information they are receiving.
The findings, published this week in the online edition of the Proceedings of the National Academy of Sciences, are the latest in a growing body of evidence suggesting that astrocytes are critically important for processing sensory information, says Mriganka Sur, the Paul E. and Lilah Newton Professor of Neuroscience at MIT and senior author of the paper.
Sur’s lab has been studying astrocytes for about five years, as part of a longstanding interest in revealing the functions of different cell types in the cortex. The star-shaped cells were first discovered and named 150 years ago, but since then, “it’s been a mystery what they do,” says Sur, who is a member of MIT’s Picower Institute for Learning and Memory and director of the Simons Center for the Social Brain at MIT.
Lead authors of the paper are graduate student Naiyan Chen and research scientist Hiroki Sugihara. Other authors are research scientist Jitendra Sharma, postdocs Gertrudis Perea and Jeremy Petravicz, and technical assistant Chuong Le.
Attention strengthens response
In this study, the researchers focused on what astrocytes do when the brain is stimulated to pay attention to a specific visual stimulus. When someone is paying close attention to something, the nucleus basalis — a structure located deep within the brain, behind the eyes — floods the brain with a neurotransmitter called acetylcholine. Some of this acetylcholine targets astrocytes in the visual cortex.
To explore how astrocytes react to this stimulation, the researchers measured what happened in the visual cortex as they showed mice several visual patterns composed of parallel lines oriented in different directions. For one of the visual patterns, the researchers also provoked the nucleus basalis to release acetylcholine at the same time. This greatly boosted calcium levels in the astrocytes, indicating high activity.
When the mice were shown the same stimuli a few minutes later, the pattern that had been presented along with acetylcholine stimulation provoked a much stronger response in neurons of the visual cortex than the other patterns.
The researchers then did the same test in genetically engineered mice whose astrocytes were disabled. In those mice, the acetylcholine released by the nucleus basalis did not strengthen neurons’ response to visual stimuli.
“If you are paying attention to something, which causes this release of acetylcholine, that leads to a long-lasting memory of that stimulus. If you remove the astrocytes, that doesn’t happen,” Sur says.
The strengthening effect lasts for tens of minutes, after which the neurons return to their original activity level in response to the selected stimulus.
“More directly than any other study to date, it illustrates the critical role of astrocytes in plasticity,” says Michael Merzenich, a professor emeritus of neuroscience at theUniversity of California at San Francisco, who was not part of the research team. “It’s a crystal-clear demonstration.”
‘Major players in brain disorders’
It is already known that acetylcholine levels drop in the brains of patients with Alzheimer’s disease. In fact, a commonly used treatment that can boost memory in Alzheimer’s patients is a drug that blocks the degradation of acetylcholine. In a follow-up study, the researchers are planning to study how astrocytes are affected in mouse models of Alzheimer’s.
Sur’s lab is also studying the effects of nucleus basalis stimulation on inhibitory neurons. Those effects are thought to be shorter term, lasting seconds or fractions of seconds.
“You cannot understand brain disorders without understanding the basic mechanisms of cortical brain function,” Sur says. “These cell types — astrocytes, inhibitory neurons — are emerging as major players in brain disorders, in unexpected ways.”
The research was funded by the National Institutes of Health and the Simons Foundation.
Source: http://web.mit.edu/newsoffice/2012/neuroscientists-shed-light-on-plasticity-0927.html
/ About us
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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