Past brain activation revealed in scans: Brain activity patterns preserve traces of previous cognitive activity
The new research stems from earlier findings in the lab of Prof. Rafi Malach of the Institute's Neurobiology Department and others that the brain never rests, even when its owner is resting. When a person is resting with closed eyes -- that is, no visual stimulus is entering the brain -- the normal bursts of nerve cell activity associated with incoming information are replaced by ultra-slow patterns of neuronal activity. Such spontaneous or "resting" waves travel in a highly organized and reproducible manner through the brain's outer layer -- the cortex -- and the patterns they create are complex, yet periodic and symmetrical.
Like hieroglyphics, it seemed that these patterns might have some meaning, and research student Tal Harmelech, under the guidance of Malach and Dr. Son Preminger, set out to uncover their significance. Their idea was that the patterns of resting brain waves may constitute "archives" for earlier experiences. As we add new experiences, the activation of our brain's networks lead to long-term changes in the links between brain cells, a facility referred to as plasticity. As our experiences become embedded in these connections, they create "expectations" that come into play before we perform any type of mental task, enabling us to anticipate the result. The researchers hypothesized that information about earlier experiences would thus be incorporated into the links between networks of nerve cells in the cortex, and these would show up in the brain's spontaneously emerging wave patterns.
In the experiment, the researchers had volunteers undertake a training exercise that would strongly activate a well-defined network of nerve cells in the frontal lobes. While undergoing scans of their brain activity in the Institute's functional magnetic resonance imaging (fMRI) scanner, the subjects were asked to imagine a situation in which they had to make rapid decisions. The subjects received auditory feedback in real time, based on the information obtained directly from their frontal lobe, which indicated the level of neuronal activity in the trained network. This "neurofeedback" strategy proved highly successful in activating the frontal network -- a part of the brain that is notoriously difficult to activate under controlled conditions.
To test whether the connections created in the brain during this exercise would leave their traces in the patterns formed by the resting brain waves, the researchers performed fMRI scans on the resting subjects before the exercise, immediately afterward, and 24 hours later. Their findings, which appeared in the Journal of Neuroscience, showed that the activation of the specific areas in the cortex did indeed remodel the resting brain wave patterns. Surprisingly, the new patterns not only remained the next day, they were significantly strengthened. These observations fit in with the classic learning principles proposed by Donald Hebb in the mid-20th century, in which the co-activation of two linked nerve cells leads to long term strengthening of their link, while activity that is not coordinated weakens this link. The fMRI images of the resting brain waves showed that brain areas that were activated together during the training sessions exhibited an increase in their functional link a day after the training, while those areas that were deactivated by the training showed a weakened functional connectivity.
This research suggests a number of future possibilities for exploring the brain. For example, spontaneously emerging brain patterns could be used as a "mapping tool" for unearthing cognitive events from an individual's recent past. Or, on a wider scale, each person's unique spontaneously emerging activity patterns might eventually reveal a sort of personal profile -- highlighting each individual's abilities, shortcomings, biases, learning skills, etc. "Today, we are discovering more and more of the common principles of brain activity, but we have not been able to account for the differences between individuals," says Malach. "In the future, spontaneous brain patterns could be the key to obtaining unbiased individual profiles." Such profiles could be especially useful in diagnosing or learning the brain pathologies associated with a wide array of cognitive disabilities.
Prof. Rafi Malach's research is supported by the Nella and Leon Benoziyo Center for Neurosciences; the Nella and Leon Benoziyo Center for Neurological Diseases; the Carl and Micaela Einhorn-Dominic Brain Research Institute; the Norman and Helen Asher Center for Human Brain Imaging; the Murray H. and Meyer Grodetsky Center for Research of Higher Brain Functions; the Kahn Family Research Center for Systems Biology of the Human Cell; the Friends of Dr. Lou Siminovitch; the Adelis Foundation; and the Mike and Valeria Rosenbloom through the Mike Rosenbloom Foundation. Prof. Malach is the recipient of the Helen and Martin Kimmel Award for Innovative Investigation; and he is the incumbent of the Barbara and Morris L. Levinson Professorial Chair in Brain Research.
Welcome to SUV System Ltd!
SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.
We have built up long term business relationship with about many companies which are stockers and authorized agents. we have a steady and reliable supply to meet customer's demands to the greatest extent .Confidently, we are able to lower your cost and support your business with our years of professional service.
SUV System Ltd is Electronic Components Distributor Supplies,Find Quality Electronic Components Supplies Products IC(Integrated Circuits),Connectors,Capacitor,Resistors,Diodes,Transistors,LED at Suvsystem.com. Sourcing Other Energy, Environment, Excess Inventory Products from Manufacturers and Suppliers at Suvsystem.com
Electronic Components distributor:http://www.suvsystem.com
Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html
IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html
LED Distributor:http://www.suvsystem.com/l/LED-1.html
Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html
Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html
Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html
Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html
SUV System Ltd insists on the managing faith ofsincereness,speciality,foresight, win-win,so we build up stable-relationship customers located all over the world, including the States, Europe, Argentina, UAE, Malaysia, Australia,and India etc
we are focus on the following fields,and hope we can help you.
AT32AP7200-ES AT32AP7200-CFUR AT32AP7002-CTUT AT32AP7002-CTUR AT32AP7002 AT32AP7001-ALUT AT32AP7001ALUT AT32AP7001 AT32AP7000-CTUT AT32AP7000CTUT AT34.C02.NC3 AT34 AT33C56C AT33C101P AT339PINXJ1004422 AT339 AT338 AT337AT AT337 AT336 AT33517 AT335 AT334 AT333 AT-3320-TT-R AT3320F AT332 AT-3311-TF-LW110-R AT33105 AT331 AT33016-3 AT330 AT-33 AT33 AT32UC3B164-Z1UT AT32UC3B164-Z1UR AT32UC3B164-AUT AT32UC3B164-AUR AT32UC3B164 AT32UC3B1256-Z1UT
http://www.suvsystem.com/a/3230.aspx
No comments:
Post a Comment