Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Neuroscientists identify how trauma triggers long-lasting memories in the brain

26.07.2005


Brain’s amygdala plays pivotal role during an emotional experience, strengthening connections between neurons



A research team led by UC Irvine neuroscientists has identified how the brain processes and stores emotional experiences as long-term memories. The research, performed on rats, could help neuroscientists better understand why emotionally arousing events are remembered over longer periods than emotionally neutral events, and may ultimately find application in treatments for conditions such as post-traumatic stress disorder.

The study shows that emotionally arousing events activate the brain’s amygdala, the almond-shaped portion of the brain involved in emotional learning and memory, which then increases a protein called "Arc" in the neurons in the hippocampus, a part of the brain involved in processing and enabling the storage of lasting memories. The researchers believe that Arc helps store these memories by strengthening the synapses, the connections between neurons.


The study will appear in today’s issue of the Proceedings of the National Academy of Sciences.

"Emotionally neutral events generally are not stored as long-term memories," said Christa McIntyre, the first author of the paper and a postdoctoral researcher in the Department of Neurobiology and Behavior in UCI’s School of Biological Sciences, working with James L. McGaugh, research professor and a fellow at the Center for the Neurobiology of Learning and Memory. "On the other hand, emotionally arousing events, such as those of September 11, tend to be well-remembered after a single experience because they activate the amygdala."

In their experiments, the researchers placed a group of rats in a well-lit compartment with access to an adjacent dark compartment. Because rats are nocturnal and prefer dark environments, they tended to enter the dark compartment. Upon doing so, however, they were each given a mild foot-shock – an emotional experience that, by itself, was not strong enough to become a long-lasting memory. Some of the rats then had their amygdala chemically stimulated in order to determine what role it played in forming a memory of the experience.

When they placed the rats that received both the mild foot-shock and the amygdala stimulation back in the well-lit compartment, the researchers found the rats tended to remain there, demonstrating a memory for the foot shock they had received in the dark compartment. These rats, the researchers found, also showed an increase in the amount of the Arc protein in the hippocampus. On the other hand, rats that received only the mild foot-shock and no amygdala stimulation showed no increase in Arc protein. When placed in the well-lit compartment, they tended to enter the dark compartment, suggesting they didn’t remember the foot shock.

"In a separate experiment, we chemically inactivated the amygdala in rats very soon after they received a strong foot-shock," McIntyre said. "We found the increase in Arc was reduced and these rats showed poor memory for the foot shock despite its high intensity. This also shows that the amygdala is involved in forming a long-term memory."

The brain is extremely dynamic, McIntyre explained, with some genes in the brain, called "immediate early genes," changing after every experience. "We know the level of the immediate early gene that makes the Arc protein increases in the brain, simply in response to an exposure to a new environment," she said. "Our findings show that this gene makes more Arc protein in the hippocampus only if the experience is emotionally arousing or important enough to activate the amygdala and to be remembered days later."

The researchers were surprised to find no change in the gene that produced the Arc protein when the rat’s amygdala was stimulated. "We weren’t expecting the gene to be uncoupled from the Arc protein," McIntyre said. "We thought an activation of the amygdala would create more gene activation in the hippocampus. But we saw the same amount of the gene in the rats, regardless of the amygdala treatment. It was the Arc protein, created by the gene, that was different. This gives us new insight into the way lasting memories are stored."

The research was supported by several grants from the National Institutes of Health. In addition to McIntyre and McGaugh, co-authors of the study include Oswald Steward, UCI; Teiko Miyashita, Kristopher D. Marjon and John F. Guzowski, the University of New Mexico Health Science Center; and Barry Setlow, Texas A&M University.

Iqbal Pittalwala | EurekAlert!
Further information:
http://www.uci.edu

More articles from Studies and Analyses:

nachricht Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>