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(Health) Memory and Amnesia
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PostPosted: Tue Oct 03, 2006 9:54 am    Post subject: (Health) Memory and Amnesia Reply with quote






What is memory? This lesson covers that. Is there a difference between what we remember just before a quiz and the events that touch us the most? What is short term memory and what is long term? These are exploratory questions that we ask in order to gain a deeper understanding of how our brains work. And when memory fails, there is amnesia - this lesson also provides link on this human condition. Explore.



Cold Spring Harbor Laboratory

Scientists debate the neurobiological underpinnings of amnesia

Cold Spring Harbor, N.Y., Mon., Oct. 3, 2006 -- A first kiss, an exotic vacation, a sports team championship, a child's first words: all are memorable events. But when someone has amnesia, have the memories been completely purged from the brain or are they simply irretrievable? Is amnesia a defect in memory storage, or memory recovery?

This has been a vexed question for more than 30 years. Most psychologists tended to support the retrieval-deficit explanation, while neuroscientists interested in how memories work at a molecular and cellular level backed the idea of storage-failure.

This disconnect has limited both scientific and clinically relevant advances. But in a collection of articles published today by the journal Learning & Memory, leaders in the field of memory studies have thoughtfully reconsidered the enigma of amnesia, as well as the methodological and conceptual problems in its study. They point out how studies of amnesia have been important in forming our current understanding of how memory works, and they propose novel ways of experimentally evaluating the neurobiological basis of memory impairment. The resulting section, entitled "The Neurobiology of Amnesia," includes eight articles, all of which are available online today at www.learnmem.org.

"Questions about the nature of amnesia are ultimately biological questions," explains Dr. Larry Squire, Professor of Psychiatry at the University of California, San Diego, and one of the contributors to the special section. "But some of the best-known and most-often-cited evidence is founded on a behavioral-psychological level of analysis. What we really need to be asking is: 'In amnesia, what actually happens to the synaptic changes that carry the memory?'"

"There is evidence that bears on that question," says Dr. Squire. In an experimental setting, animals can "recover" from amnesia under a variety of conditions, something that should be impossible if the memory was not initially stored. But the major challenge is to experimentally assess whether an animal has truly recovered a memory or simply re-learned a task.

Because amnesia is rarely complete and there is often some residual performance ability, it can be argued by supporters of the storage-failure theory that any "recovery" from amnesia reflects new learning added onto the residual memory. The retrieval-failure theory cannot easily be attacked because one can argue that a memory remains inaccessible until the appropriate retrieval cues are provided.

Dr. Karim Nader, Professor of Psychology at McGill University (Canada), is the guest editor of the Learning & Memory special amnesia section. "This compilation of articles brings many of the perspectives concerning the nature of amnesia side-by-side for consideration," he says. "We hope that it will inspire readers to think of new ways to bridge the different positions and levels of analyses, and that it will give new momentum to the search for answers to the fundamental nature of amnesia."

###
ABOUT LEARNING & MEMORY: Learning & Memory (www.learnmem.org) is a leading international peer-reviewed research journal devoted to work in the neurosciences. Spanning genes to behavior, it publishes studies that incorporate a broad range of approaches for understanding the neurobiology of learning and memory in humans and other species. According to ISI's Journal Citation Reports, Learning & Memory is currently ranked in the top 15% of journals in the neuroscience field.

ABOUT COLD SPRING HARBOR LABORATORY PRESS: Cold Spring Harbor Laboratory Press is an internationally renowned publisher of books, journals, and electronic media located on Long Island, New York. It is a division of Cold Spring Harbor Laboratory, an innovator in life science research and the education of scientists, students, and the public. For more information, visit www.cshlpress.com.

*************************************************************

Questions to explore further this topic:

The Brain and the Central nervous System

http://www.paete.org/forums/viewtopic.php?t=864

What is memory?

http://www.kidshealth.org/kid/.....emory.html
http://www.exploratorium.edu/memory/index.html
http://www.bbc.co.uk/radio4/me.....mory.shtml
http://en.wikipedia.org/wiki/Memory
http://www.memorylossonline.co.....emory.html
http://skepdic.com/memory.html

What are the types of human memory?

http://www-static.cc.gatech.ed.....emory.html
http://www.intelihealth.com/IH.....dmtContent

Why is memory important in learning?

http://www.engines4ed.org/hype.....25-pg.html
http://comp.uark.edu/~jdharris/cogmem.html

Memory: Classroom activities

http://teachhealthk-12.uthscsa.....Memory.htm

What is your earliest memory?

http://amos.indiana.edu/librar.....nesia.html
http://www.exploratorium.edu/m.....index.html
http://pbskids.org/zoom/fromyo.....emory.html

The development of memory: Infancy memory

http://www.u.arizona.edu/~vanpettc/326/devel.html

What are the memory processes?

http://www.u.arizona.edu/~dusa.....es/CH5.ppt
http://www.u.arizona.edu/~dusa.....es/CH6.ppt

The Anatomy of memory

http://www.italianacademy.colu.....Memory.pdf

What is short term memory?

http://coe.sdsu.edu/eet/Articl...../start.htm
http://wik.ed.uiuc.edu/index.p.....short_term

Short Term Memory Test

http://faculty.washington.edu/chudler/stm0.html

What is long term memory?

http://coe.sdsu.edu/eet/articl...../start.htm
http://wik.ed.uiuc.edu/index.php/Memory,_long_term
http://www.uidaho.edu/psyc325/lessons/05/index.htm

Long term memory and learning

http://simon.lrdc.pitt.edu/~sa.....TMPOST.ppt

What are the parts of long term memory?

http://online.sfsu.edu/~forema.....emory.html

Molecular basis of long term memory

http://www.news.cornell.edu/Ch.....study.html
http://today.uci.edu/news/rele.....p?key=1518

What is eidetic (photographic?) memory?

http://amos.indiana.edu/librar.....emory.html
http://www.ababasoft.com/games/eidetic01.htm
http://serendip.brynmawr.edu/b.....naudo.html
http://wik.ed.uiuc.edu/index.php/Memory,_visual

What is false memory syndrome?

http://serendip.brynmawr.edu/b.....nnery.html

Does the sense of smell affect memory?

http://serendip.brynmawr.edu/b.....Smith.html

How does alcohol affect memory?

http://www.duke.edu/~amwhite/Blackouts/index.html
http://pubs.niaaa.nih.gov/publ.....3/aa63.htm

Memory: The Key to Consciousness (2005)

http://www.nap.edu/books/03090.....index.html

Memory experiments

http://faculty.washington.edu/.....emory.html

How can one improve one's memory?

http://www.mtsu.edu/~studskl/mem.html
http://www.helpguide.org/life/improving_memory.htm

What is memory loss?

http://www.nia.nih.gov/NR/rdon.....ryloss.pdf
http://www.nlm.nih.gov/medline.....003257.htm

What are the reversible causes of memory loss?

http://www.intelihealth.com/IH.....dmtContent

Memory loss with aging, what is normal and what is not?

http://familydoctor.org/124.xml

How is memory loss treated?

http://www.intelihealth.com/IH.....dmtContent

What is agnosia?

http://www.ninds.nih.gov/disor.....gnosia.htm

What is amnesia?

http://en.wikipedia.org/wiki/Amnesia
http://www.bbc.co.uk/radio4/me.....esia.shtml
http://news.bbc.co.uk/2/hi/hea.....167771.stm

What is childhood amnesia?

http://www.bbc.co.uk/radio4/me.....esia.shtml

Do popular media (movies) correctly depict amnesia?

http://www.pubmedcentral.nih.g.....tid=535990

What is memory in computers?

http://www.kingston.com/tools/umg/umg01a.asp
http://www.abilityhub.com/information/ram.htm

GAMES

http://www.exploratorium.edu/m.....index.html
http://www.woodlands-junior.ke.....ional/#mem
http://pbskids.org/caillou/games/memory.html
http://www.nationalgeographic......pycat.html


Last edited by adedios on Sat Jan 27, 2007 4:42 pm; edited 2 times in total
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PostPosted: Wed Nov 08, 2006 3:49 pm    Post subject: How the brain weaves a memory Reply with quote

Cell Press
8 November 2006

How the brain weaves a memory

Memories of events comprise many components--including sights, sounds, smells, and tastes. Somehow the many features of an episodic memory are woven together into a coherent whole, and researchers have had little understanding of how this binding takes place as the memories are processed by the brain's memory center, the hippocampus. A central question has been whether the hippocampus receives an "episodic packet," or a collection of perceptual strands that it must integrate into a memory.

In an article in the November 9, 2006, issue of the journal Neuron, published by Cell Press, Melina Uncapher and colleagues report experiments with human volunteers that shed important light on this process.

In their experiments, the researchers presented the subjects with series of "study" words on a display screen, as their brains were scanned using functional magnetic resonance imaging (fMRI). This technique involves using harmless radio waves and magnetic fields to measure blood flow to brain regions, which reflects brain activity. As their brains were scanned, the subjects were shown words of different colors and that were located in different quadrants of the display screen.

Later, the subjects were presented a collection of words including both the study words and new words. They were asked to recall whether the words were old or new, and for the old words, their color and location.

The researchers then correlated fMRI data on the brain regions active during the study phase with the data on the subjects' later retrieval of the features of these study words. They found that, indeed, regions of the brain involved in processing color and location were active during formation of memories for those features.

However, importantly, they found that the subjects' successful retrieval of both features--versus only color or location--was uniquely associated with enhanced activity in yet another brain region called the intraparietal sulcus, which has been strongly implicated in other studies as important in "perceptual binding" of multiple features of stimuli.

Thus, the researchers concluded that "The findings suggest that the encoding of disparate features of an episode into a common memory representation requires that the features be conjoined in a common perceptual representation when the episode is initially experienced."


###
The researchers include Melina R. Uncapher and Michael D. Rugg of University of California at Irvine in Irvine, California; Leun J. Otten of University College London in London, United Kingdom.

This research was supported by the National Institute of Mental Health (1R01MH074528); L.O. was supported by the Wellcome Trust. The authors thank the members of the UCI Research Imaging Center for their assistance with fMRI data acquisition.

Uncapher et al.: "Episodic Encoding Is More than the Sum of Its Parts: An fMRI Investigation of Multifeatural Contextual Encoding." Publishing in Neuron 52, 547–556, November 9, 2006. DOI 10.1016/j.neuron.2006.08.011 www.neuron.org
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PostPosted: Fri Nov 10, 2006 8:21 pm    Post subject: Hopkins researchers discover how brain protein might control Reply with quote

Johns Hopkins Medical Institutions
10 November 2006

Hopkins researchers discover how brain protein might control memory

Researchers at Johns Hopkins have figured out how one particular protein contributes to long-term memory and helps the brain remember things longer than an hour or two. The findings are reported in two papers in the Nov. 9 issue of Neuron.

The protein, called Arc, has been implicated in memory-linked behaviors ranging from song learning in birds to rodents being aware of 3-D space. In people, Arc may be one culprit behind certain long-term memory-based behaviors like drug addiction, the researchers say.

"We think Arc controls how brain cells learn and associate behaviors and remember them over a long period of time," says Paul F. Worley, M.D., professor of neuroscience and neurology at Hopkins and director of both studies. "For example, the person who quits smoking can wean himself from cravings at home, at work or outside. But if you put him in a bar with a drink in his hand, his brain remembers that former association and suddenly the craving returns. These types of long-term associations are memories wired in your brain."

Years ago, Worley and his colleagues, studying laboratory rats, found that their brains made lots of Arc protein while the animals were awake and active. In fact, it has been long known that stimulating individual nerve cells - by an act as simple as exploring new environs, for example - causes the cells to make more Arc protein almost immediately. "Arc is an instant and reliable readout for active cells in the brain," says Worley. But although scientists knew that active cells were making copious amounts of Arc, no one knew exactly what Arc was doing in those cells until now.

To figure out what Arc was doing, the Hopkins team looked for what other proteins Arc "plays" with. Using Arc protein as bait, they went on a molecular fishing expedition in a pond filled with other proteins normally found in the brain and hooked two known to be involved in transporting materials into and out of cells.

"Moving things in and out of cells is critical for normal brain cell function. We were extremely excited that Arc might somehow be involved in this transport because it links transport to memory formation," says Worley. "This brings us one step closer to understanding how the brain saves memories."

According to Worley, memories form when nerve cells connect and "talk" to other nerve cells. It's thought that the stronger these connections are, the stronger the memory.

Like the childhood game called Telephone, where one person taps her neighbor and whispers a message that is passed on in similar fashion to the next person in line, nerve cells connect and "talk" to each other by relaying messages - usually by passing small chemicals - from cell to cell.

When nerve cells connect with each other in the brain, one cell releases chemicals into the space between it and its neighbor. The neighboring cell has protein receptors on its surface that capture the released chemicals. The cell that captures these chemicals then swallows up the receptor-chemical complexes, removing the receptors from the cell's surface. The more receptors present, according to Worley, the stronger the connection between the two cells. New receptors constantly replace the swallowed-up ones.

The two proteins that came out of the Arc fishing expedition - known as dynamin and endophilin - previously were known to be critical for this swallowing action. And, it turns out that Arc controls these two proteins and therefore controls how often cells swallow receptors from their surfaces.

When the researchers altered Arc so that it was unable to bind these two proteins, cells were unable to "swallow" and wound up with more receptors than normal on their surfaces. Adding more Arc to cells caused the opposite to happen; the cells hyperactively swallowed up too many receptors, leaving few at the surface.

Unfortunately, it's possible to over-excite a cell to death, says Worley, and if the excitation controls come off, the strength of long-term memory is altered.

So what does Arc's control over brain cell receptors mean for our ability to remember where we put the car keys? "We know that animals lacking Arc live only in the here and now. They learn fine in the short term, but tomorrow they will need to relearn everything," says Worley. And in the case of long-term memories that are better forgotten, such as that cigarette craving while sitting in a bar, a better understanding of how these memories form promises hope that there might be a way in the future to forget them entirely.

###
Researchers were supported by grants from the National Institute of Mental Health, the National Institute of Deafness and Other Communication Disorders, the Howard Hughes Medical Institute and the Human Frontier Science Program Organization.

Authors of the two papers are Shoaib Chowdhury, Jason Shepherd, Gavin Rumbaugh, Hiroyuki Okuno, Gregory Lyford, Jing Wu, Richard Huganir and Worley of Hopkins; Ronald Petralia of National Institute on Deafness and Other Communication Disorders at the National Institutes of Health; and Niels Plath and Dietmar Kuhl of Freie Universitat Berlin in Germany.

On the Web: http://neuroscience.jhu.edu/
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PostPosted: Tue Nov 14, 2006 10:47 am    Post subject: Taking Tests Improves Memory Reply with quote

Taking Tests Improves Memory

By Ker Than
LiveScience Staff Writer
posted: 14 November 2006
08:36 am ET

Students, don't cringe, but new research suggests that the very act of taking a test is enough to enhance long-term memory. Furthermore, testing helps students remember not only what they studied for the test, but also related, non-tested concepts.

The results "imply that as long as students retrieved a concept, other related concepts should also receive a boost," the researchers write in the November issue of the Journal of Experimental Psychology: General.

In one experiment, a group of 84 undergraduates were given two sets of facts about the biology and lifestyle of tropical toucan birds. The researchers divided the students into three groups, with one group taking a test immediately after studying the first set of facts, before receiving the second set to study for a final test.

For the full article:

http://www.livescience.com/hum.....emory.html
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PostPosted: Tue Nov 28, 2006 7:53 am    Post subject: Tales of the unexpected Reply with quote

Wellcome Trust
27 November 2006

Tales of the unexpected
How the brain detects novelty


When you sit down to watch a DVD of your favourite film, the chances are that you are able to predict the exact sequence of events that is about to unfold. Without our memories we would not only be unable to remember our past but perhaps more importantly predict the future. Scientists believe they may have identified how the brain allows us to anticipate future events and detect when things do not turn out as expected.

Dr Dharshan Kumaran and Dr Eleanor Maguire at the Wellcome Trust Centre for Neuroimaging at University College London have shown that the hippocampus, the area of the brain believed to play a crucial role in learning and memory, makes predictions of what will happen next by automatically recalling an entire sequence of events in response to a single cue. The research is published today in the journal Public Library of Science Biology.

Using an fMRI scanner, which uses changes in blood flow within the brain to provide measurements of brain activity, Dr Kumaran and Dr Maguire were able to show how the brain reacts to unexpected changes in a sequence of images. A subject is shown a series of four images which are then repeated in a different order. By changing the order of only the final two images, the researchers found that the hippocampus appeared to be predicting which image would come next and reacting when an unexpected image appeared.

"These experiments indicate that the hippocampus acts as a sort of comparison device, matching up past and present experience” says Dr Kumaran. "It does not appear to be reacting to novelty as such, but rather to discrepancies between what it expects to see and what it actually sees."

The results imply that when the hippocampus is prompted by a cue, it recalls a sequence of associated memories, a process that may explain how seeing a particular person's face or listening to a piece of music can trigger the recollection of an entire past experience. Furthermore, the hippocampus would appear to perform a critical comparison between our past and present experiences alerting us to unexpected occurrences in our environment, such as changed layout.

"Patients with damaged hippocampi, such as those with Alzheimer's Disease, often have trouble remembering sequences of events or finding their way around" explains Dr Kumaran. "This would seem to be because the damaged hippocampus is unable to rapidly bind together the many different components of our experiences into a coherent whole.”
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PostPosted: Wed Dec 06, 2006 7:39 pm    Post subject: Tracing the formation of long-term memory Reply with quote

Baylor College of Medicine
December 6, 2006

Tracing the formation of long-term memory

The formation of long-term memory in fruit flies can be demonstrated by the influx of calcium into cells called mushroom body neurons that occurs after special training that includes periods of rest, said researchers from Baylor College of Medicine (BCM) in a report that appears in the current issue of the journal Neuron.

"We have strong evidence that this is really a molecular change that is involved in long-term memory," said Dr. Ronald Davis, professor of molecular and cellular biology at BCM. "This appears to be an authentic memory trace for long-term memory."

Davis and his colleagues used spaced training to teach the flies to associate an odor with a mild electric shock. This method gives the fly a training trial, then a rest and then another trial. The rest is critical in inducing long-term memory that can last days. In this study, the five spaced trials produced a memory that lasted for more than a day. They then used a technique called "functional imaging" to see when the memory formed in the fly’s brain.

"Before training, we could see some calcium flowing into the mushroom body neurons when the flies were exposed to odor," said Davis. When they exposed the fruit flies or Drosophila to the odor 24 hours after spaced training, they saw much more calcium flowing into the mushroom body neurons. The increased calcium influx paralleled the long-term memory of the flies. Using special laboratory techniques, he and others in the lab showed that they could block the calcium influx by blocking the function of a protein critical to making the new synapses associated with long-term memory.

###
Drs. Dinghui Yu and David-Benjamin G. Akala also took part in this research. Funding for this project came from the Mathers Charitable Trust, the National Institute of Neurological Disorders and Stroke and the Welch Foundation.
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PostPosted: Thu Jan 04, 2007 9:37 am    Post subject: Brain Uses Past to Peer Into Future Reply with quote

Brain Uses Past to Peer Into Future

By E.J. Mundell
HealthDay Reporter
posted: 03 January 2007
02:32 pm ET

(HealthDay News) -- Your past may be key to your dreams for the future, new research suggests.

In experiments using high-tech brain imaging, scientists have found that neurological memory centers are highly active whenever people envision upcoming events.

"It shows us that memory is just as important to imagining the future as it is to remembering the past," said lead researcher Karl Szpunar, a graduate student in the department of psychology at Washington University, in St. Louis.

Besides furthering understanding of the brain, the findings might help research into amnesia and depression, Szpunar added.

His team published its findings in this week's issue of the Proceedings of the National Academy of Sciences.

For the full article:

http://www.livescience.com/healthday/600588.html
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PostPosted: Sun Feb 18, 2007 8:34 am    Post subject: Infants Form Memories, Then Forget Reply with quote

Infants Form Memories, Then Forget

By Randolph E. Schmid
Associated Press
posted: 17 February 2007
09:10 am ET


SAN FRANCISCO (AP)—Adults thinking back rarely can remember anything before preshool, but those bright infant eyes staring back at mommy and daddy really are forming memories. It's just that babies also forget. In fact, babies' rate of forgetting is even faster than that of adults, Patricia J. Bauer of Duke University said Friday at the annual meeting of the American Association for the Advancement of Science.
Bauer was part of a panel discussing "infant amnesia,'' the puzzling inability of people to remember events early in life.

Researchers have long speculated that babies' brains were simply unable to form memories, but Bauer said new research indicates that is incorrect.

For the full article:

http://www.livescience.com/hum.....ories.html
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PostPosted: Tue Feb 20, 2007 8:27 am    Post subject: Problem forgetting may be a natural mechanism gone awry Reply with quote

Problem forgetting may be a natural mechanism gone awry

John Pastor
02/19/2007

Better tie that string around your finger a little tighter.

It may turn out the reason some people grow increasingly forgetful as they age is less about how old they are and more about subtle changes in the way the brain files memories and makes room for new ones - differences perhaps better blamed on patterns of cell-to-cell communication than the number of birthday candles decorating the cake.

A researcher with the McKnight Brain Institute of the University of Florida has found that rats become forgetful because a routine part of the memory process falls out of kilter, no matter their ages.

This change seems to be related to the chemicals necessary for brain cells to communicate with each other. The findings, published this month in the online edition of Neurobiology of Learning and Memory, expand the possibility that drugs or therapies could be developed to tune up the brain's memory mechanisms.

"Aging is associated with an increased rate of forgetting," said Thomas Foster, Ph.D., the Evelyn F. McKnight chair for brain research in memory loss at the College of Medicine. "My work indicates that the problem may be a slight shift in a normal forgetting mechanism."

Scientists believe a memory forms when communication increases between brain cells called neurons. During memory formation, signals jump across narrow gaps between cells called synapses, and this output becomes increasingly larger.

But for this activity to efficiently create a memory, it helps if signaling decreases among less-involved neurons. It's like quieting other people in the room so you can have a phone conversation. Scientists call the process of decreasing the signal at less-involved synapses "long-term depression," or LTD.

"This is a normal process that helps with the sculpting of memory," Foster said. "After all, we do not remember everything in perfect detail and we would not want to. This same mechanism probably is used to clear the brain circuits and make them ready to be used the next day. However, this mechanism in excess may lead to rapid forgetting as seen during brain aging."

Foster's lab group used aged and young rats to examine the relationships between LTD, aging and memory. The animals were trained to find a hidden platform to climb out of a pool of water - something they learned quickly with repetition.

When the researchers examined the animals' neurons and used a slow, weak electrical signal to make the synapses less sensitive - an effort to squelch or depress the cellular communication - he found that the samples from younger animals and older animals that had the highest memory scores throughout their lives were more resistant to the interference. However, aged animals with impaired memories displayed what was termed as "robust long-term depression."

Going back to the phone call example, not only did the rest of the room get quieter, the callers did, too. The assumption is if a memory is encoded by making synapses stronger, then memory can be disrupted by something that weakens those connections.

"When we see someone we know or perhaps even ourselves becoming more forgetful, we now know that this is not an inevitable process," Foster said. "Further, as we begin to understand the mechanisms of memory, it becomes possible to predict promising targets for therapeutic strategies aimed at postponing or alleviating age-related memory impairment."

Foster said it will be important to understand whether a change in cellular signaling is necessary to enable new memories to be formed by discarding old ones.

"The basic gist is that information storage requires a balance between mechanisms that make synapses stronger and weaker," said Mark F. Bear, Ph.D., director of the Picower Institute for Learning and Memory at the Massachusetts Institute of Technology, who was not involved with the research. "In aging and disease, if that balance is disrupted to favor LTD, the unchecked synaptic weakening leads to memory loss. The good news is we are developing a good understanding of these mechanisms, and that will help us find ways to protect memory."

Foster's work was supported by the National Institutes of Health and an Evelyn F. McKnight Brain Research grant.
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PostPosted: Wed Feb 21, 2007 7:34 am    Post subject: How the Brain's Overstuffed Filing System Fails Reply with quote

How the Brain's Overstuffed Filing System Fails

By Jeanna Bryner
LiveScience Staff Writer
posted: 20 February 2007
12:10 pm ET

Age is not entirely to blame for forgetfulness.

The reason that some people are absentminded and others have minds like a steel-trap might have more to do with how the brain files memories and makes room for new ones, new research suggests.

The overstuffed file system that collects daily to-do’s while keeping track of childhood memories has remained an enigma, especially regarding the mechanism for such mega-bit storage amidst the deluge of incoming bytes.

Every minute, sensory data enters your brain in the form of electrical signals that jet from neuron to neuron via intersections called synapses. Scientists think memories form when this communication between brain cells increases.

For the full article:

http://www.livescience.com/hum....._file.html
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PostPosted: Thu Mar 15, 2007 7:08 am    Post subject: Research Reveals How Memories Are Made Reply with quote

Research Reveals How Memories Are Made

By Robert Preidt
HealthDay Reporter
posted: 14 March 2007
01:16 pm ET

(HealthDay News) -- New research shows memories are made in the brain using the same "machinery" that individual cells use to control their genes during embryonic development.

In tests on rats, researchers Courtney Miller and David Sweatt of the University of Alabama at Birmingham concluded that a process called DNA methylation plays a role in the creation of memories.

During DNA methylation, molecules called methyl groups attach to genes and switch them off. On the other hand, a lack of methyl groups means that genes remain activated. Methylation is used by cells during embryonic development to deactivate certain genes so that cells can specialize as they form into different types of cells.

For the full article:

http://www.livescience.com/healthday/602723.html
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PostPosted: Sun Apr 01, 2007 7:22 am    Post subject: Selective amnesia -- How a traumatic memory can be wiped out Reply with quote

CNRS
31 March 2007

Selective amnesia -- How a traumatic memory can be wiped out

French CNRS scientists in collaboration have shown that a memory of a traumatic event can be wiped out, although other, associated recollections remain intact. This is what a scientist in the Laboratory for the Neurobiology of Learning, Memory and Communication (CNRS/Orsay University), working with an American team, has recently demonstrated in the rat. This result could be used to cure patients suffering from post-traumatic stress.

Recalling an event stored in the long-term memory triggers a reprocessing phase: the recollection then becomes sensitive to pharmacological disturbances before being once more stored in the long-term memory. Is drug therapy capable of wiping out the initial memory, and only that memory?

The scientists trained rats to be frightened of two distinct sounds, making them listen to these sounds just before sending an electric shock to their paws. The next day, they gave half of the rats a drug known to cause amnesia for events recalled from memory, and played just one of the sounds again. When they played both sounds to the rats on the next day, those which had not received the drug were still frightened of both sounds, while those which had received the drug were no longer afraid of the sound they had heard under its influence. Recalling the memory of the electric shock associated with the sound played while rats were under the influence of a drug thus meant that the memory was wiped out by the drug, leaving intact the memory associated with the other sound.

The researchers also recorded the neuronal activity of rats in the amygdale, an area of the brain associated with emotional memory. Neuronal activity increased when remembering the traumatic memory, but diminished in drugged rats. This result showed that pharmacological disturbance of the memory recalled did indeed consist in selectively wiping out this memory, and only this memory. This is the first demonstration that a memory can be modified or even wiped out at the cellular level, permanently and independently of other memories associated with it.

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BIBLIOGRAPHY

Synapse-specific reconsolidation of distinct fear memories in the lateral amygdale, V. Doyère, J. Debiec, M.-H. Monfils, J. E Schafe, J. E LeDoux, Nature Neuroscience, doi :10.1038/nn1871 (2007). Advanced online publication on March 11, 2007
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PostPosted: Mon Apr 09, 2007 12:20 pm    Post subject: Key to a Good Memory: Forget a Few Things Reply with quote

Key to a Good Memory: Forget a Few Things

By Sara Goudarzi
LiveScience Staff Writer
posted: 09 April 2007
09:43 am ET

Childhood memories might best be kept in a photo album, not in your mind. Turns out, storing old memories can make you forget an important appointment or what you needed to buy at the store today.

Too many long-term memories make it hard to properly filter new information and process short-term memories, according to a study last month in the Proceedings of the National Academy of Sciences.

"In our world, we are constantly bombarded by new information so we are constantly filtering, and if we did not do this, we would be overwhelmed," said study team member Gaël Malleret of Columbia University Medical Center.

The new research indicates that those with better working memory may have fewer new neurons being developed in their hippocampus—a region of the brain involved in formation of memories. This "helps them forget old and useless information sooner and enables them to take in new information faster,” Malleret said.

For the full article:

http://www.livescience.com/hum.....rload.html
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PostPosted: Wed Apr 18, 2007 7:47 am    Post subject: Forming social memories Reply with quote

CNRS
18 April 2007

Forming social memories

Does a specific memory exist for events involving humans? French researchers from the Vulnerability, Adaptation and Psychopathology Laboratory (CNRS/Université Paris VI) and Canadian researchers from Douglas Hospital, McGill University (Montreal) have identified the internal part of the prefrontal cortex as the key structure for the memory formation of social information.

Social events like a party with friends, a work meeting or a row with a spouse are an integral part of daily life. Our ability to remember these events, and more particularly to remember the people and the relationship we have with them, is absolutely vital if we are to be well adapted to our social life. Different parts of the brain, particularly the hippocampus, are directly involved in learning and memory. Some of these regions are specialized in learning certain types of information, such as the amygdala, which is specialized in the memory of emotions.

The French team (led by Philippe Fossati ) and Canadian team have just identified a specific region of the frontal cortex which, they claim, is specialized in recording and learning social information. They used functional magnetic resonance imaging to measure the brain activity of 17 volunteers as they performed memory tasks involving pictures of social scenes (people and interactions) and nonsocial scenes (landscapes with no humans). This enabled them to identify the internal part of the prefrontal cortex, called the medial prefrontal cortex, as the key structure for encoding the social information in an image.

Previous studies carried out by the same researchers had associated this prefrontal region to processes of thinking about oneself and others. Their work suggests that, over and above emotions, the analysis of specifically human information could facilitate learning and remembering, by using brain structures specialized in the analysis of mental states and empathy. This opens up important perspectives for understanding the mechanisms of human expressions and mental disorders (e.g. schizophrenic disorders and autism), which affect social and relational skills.


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BIBLIOGRAPHY

Modulation of memory formation by stimulus content: specific role of the medial prefrontal cortex in the successful encoding of social pictures, Harvey, P.O., Fossati, P., Lepage, M. Journal of Cognitive Neuroscience, February 2007.
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PostPosted: Wed Apr 25, 2007 5:39 pm    Post subject: Moving Your Eyes Improves Memory, Study Suggests Reply with quote

Moving Your Eyes Improves Memory, Study Suggests

By Melinda Wenner
Special to LiveScience
posted: 25 April 2007
11:14 am ET

If you’re looking for a quick memory fix, move your eyes from side-to-side for 30 seconds, researchers say.

Horizontal eye movements are thought to cause the two hemispheres of the brain to interact more with one another, and communication between brain hemispheres is important for retrieving certain types of memories.

Previous studies have suggested that horizontal eye movements improve how well people recall specific words they have just seen. But Andrew Parker and his colleagues at Manchester Metropolitan University in England wanted to know whether such eye movements might also help people recognize words they have just seen.

Recognition memory differs from recall memory in that people trying to recognize words tend to make false memory errors called source monitoring errors. This occurs when they recognize words but attribute their familiarity to the wrong source—they might think they just read the words, when they had actually heard them in a conversation earlier that day, for example.

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http://www.livescience.com/hum.....emory.html
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PostPosted: Wed May 16, 2007 8:59 am    Post subject: Mice Find Lost Memories Reply with quote

Mice Find Lost Memories
By Corey Binns, Special to LiveScience

posted: 16 May 2007 09:03 am ET

Long lost memories can be recovered in mice suffering from recall problems similar to those associated with Alzheimer's disease in humans.

The memories of mice with neuronal damage improved when the animals lived in enriched environments or when they were given a new class of experimental drugs, said MIT neurobiologist Li-Huei Tsai.

To instill long-term memories, Tsai and her colleagues exposed mice to memorable situations, such as a shock in a certain cage. Later, it took no time for the mice to freeze in fear as soon as they were placed a shock box. After four weeks of training, the researchers caused some neural degeneration in the mice. After the brain damage, the mice no longer remembered their experiences in the shock box.

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http://www.livescience.com/hea.....ories.html
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PostPosted: Fri Jun 08, 2007 9:39 am    Post subject: Origin of Deja Vu Pinpointed Reply with quote

Origin of Deja Vu Pinpointed
By Dave Mosher, LiveScience Staff Writer

posted: 07 June 2007 02:01 pm ET

The brain cranks out memories near its center, in a looped wishbone of tissue called the hippocampus. But a new study suggests only a small chunk of it, called the dentate gyrus, is responsible for “episodic” memories—information that allows us to tell similar places and situations apart.

The finding helps explain where déjà vu originates in the brain, and why it happens more frequently with increasing age and with brain-disease patients, said MIT neuroscientist Susumu Tonegawa. The study is detailed today in the online version of the journal Science.

Like a computer logging its programs’ activities, the dentate gyrus notes a situation’s pattern—it’s visual, audio, smell, time and other cues for the body’s future reference. So what happens when its abilities are jammed?

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http://www.livescience.com/hea.....ja_vu.html
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PostPosted: Sat Jun 09, 2007 7:31 am    Post subject: Past Impressions Reply with quote

Week of June 9, 2007; Vol. 171, No. 23 , p. 363

Past Impressions
Prior relationships cast a long shadow over our social lives

Bruce Bower

In a 1948 book, psychoanalyst Theodore Reik described an extraordinary "Dr. Jekyll and Mr. Hyde"–type identity change that he underwent in the minds of many patients during therapy sessions. At the start of each encounter, Reik wrote, patients perceived a bald, elderly man with a big nose and glasses who presented a thoughtful, friendly demeanor. In other words, they saw the therapist for who he actually was.

For the full article:

http://sciencenews.org/articles/20070609/bob10.asp
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PostPosted: Wed Jun 13, 2007 9:22 am    Post subject: Study: Discriminating fact from fiction in recovered memorie Reply with quote

Association for Psychological Science
13 June 2007

Study: Discriminating fact from fiction in recovered memories of childhood sexual abuse

A decade or so ago, a spate of high profile legal cases arose in which people were accused, and often convicted, on the basis of “recovered memories.” These memories, usually recollections of childhood abuse, arose years after the incident occurred and often during intensive psychotherapy.

So how accurate are recovered memories" The answer is not so clear. In fact, this question has lead to one of the most contentious issues in the fields of psychology and psychiatry.

Elke Geraerts, a postdoc of psychology at Harvard University and Maastricht University, the Netherlands, hoped to settle some of the controversy by enacting a large-scale research study examining the validity of such memories.

Recovered memories are inherently tricky to validate for several reasons, most notably because the people who hold them are thoroughly convinced of their authenticity. Therefore, to maneuver around this obstacle Geraerts and her colleagues attempted to corroborate the memories through outside sources.

The researchers recruited a sample of people who reported being sexually abused as children and divided them based on how they remembered the event. The memories were categorized as either “spontaneously recovered” (the participant had forgotten and then spontaneously recalled the abuse outside of therapy, without any prompting), “recovered in therapy” (the participant had recovered the abuse during therapy, prompted by suggestion) or “continuous” (the participant had always been able to recall the abuse).

Once all of the information was gathered, interviewers, who were blind to the type of abuse memory, queried other people who could confirm or refute the abuse events (other people who heard about the abuse soon after it occurred, other people who reported also having been abused by the same perpetrator, or people who admitted having committed the abuse him/herself).

The results, published in the July issue of Psychological Science, a journal of the Association for Psychological Science, showed that, overall, spontaneously recovered memories were corroborated about as often (37% of the time) as continuous memories (45%). Thus, abuse memories that are spontaneously recovered may indeed be just as accurate as memories that have persisted since the time the incident took place. Interestingly, memories that were recovered in therapy could not be corroborated at all.

Although the absence of confirmation that the abuse had happened does not imply that the memory is false, the findings of this study show that memories recovered in therapy should be viewed with a cautious eye, as “the therapy context often involves an explicit effort to unearth forgotten memories and thereby raises the opportunity for suggestion.”


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Psychological Science is ranked among the top 10 general psychology journals for impact by the Institute for Scientific Information.

The study is part of an ongoing research project examining recovered memories. For more information, go to www.personeel.unimaas.nl/e.geraerts
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PostPosted: Fri Jun 22, 2007 9:07 am    Post subject: Blind People Have Superior Memory Skills Reply with quote

Blind People Have Superior Memory Skills
By Charles Q. Choi, Special to LiveScience

posted: 21 June 2007 04:28 pm ET

Blind people are whizzes at remembering things in the right order, scientists now find.

In the absence of vision, the world is experienced as sequences, explained neurobiologist Ehud Zohary of Hebrew University in Jerusalem. For instance, to identify otherwise indistinguishable objects, such as different brands of yogurt that vary only in their labeling, the blind typically place objects in arrangements of their own making and give mental tags for each of them, such as “the second item on the left.”

Zohary and his colleagues reasoned that since the blind constantly use memory strategies to remember things are, that “practice makes perfect,” giving the blind superior memory skills for other tasks.

For the full article:

http://www.livescience.com/hea.....izzes.html
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PostPosted: Tue Jul 03, 2007 8:06 am    Post subject: New Drug Deletes Bad Memories Reply with quote

New Drug Deletes Bad Memories
By Bill Christensen

posted: 02 July 2007 09:24 am ET

Do you have a really bad memory, or past heartache, that you would prefer to forget?

Researchers at Harvard and McGill University (in Montreal) are working on an amnesia drug that blocks or deletes bad memories. The technique seems to allow psychiatrists to disrupt the biochemical pathways that allow a memory to be recalled.

In a new study, published in the Journal of Psychiatric Research, the drug propranolol is used along with therapy to "dampen" memories of trauma victims. They treated 19 accident or rape victims for ten days, during which the patients were asked to describe their memories of the traumatic event that had happened 10 years earlier. Some patients were given the drug, which is also used to treat amnesia, while others were given a placebo.

For the full article:

http://www.livescience.com/hea.....ories.html
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PostPosted: Thu Jul 12, 2007 1:56 pm    Post subject: How to Suppress Bad Memories Reply with quote

How to Suppress Bad Memories
By LiveScience Staff

posted: 12 July 2007 02:04 pm ET

Scientists have uncovered a two-step process by which our brains can supposedly suppress emotional memories.

The finding, detailed in the July 13 issue of the journal Science, has implications for those suffering from emotional disorders such as depression.

In the study, 16 test subjects were asked to commit to memory 40 different pairs of pictures, consisting of a “neutral” human face and a disturbing picture such as a car crash or a wounded soldier.

After memorizing each pair, the subjects were placed in a functional MRI brain scanner. They were shown only the face images and asked to either think or not think about the disturbing image previously associated with it.

For the full article:

http://www.livescience.com/hea.....press.html
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PostPosted: Wed Jul 18, 2007 10:38 am    Post subject: Research study describes the role part of the brain plays in Reply with quote

Universitat Autonoma de Barcelona
17 July 2007

Research study describes the role part of the brain plays in memory
A research with experimental rats carried out by the Institute of Neuroscience of the UAB describes the brain region connected to how our declarative memory functions. According to this experiment, part of the prefrontal cortex plays a key role in the social transmission of food preference. This research has helped learn more about how this type of memory functions. In the future, this information could be useful to find new treatment for diseases that affect the memory, such as Alzheimer's disease.

Declarative memory is described as a flexible, conscience and associative type of memory (i.e., it is based on relations between different stimuli). It differs from other types of memories that allow us to recall effective or emotionally-charged data, or carry out processes such as riding a bicycle or playing an instrument. Declarative memory allows us to remember things such as specific moments of our lives, names of people, what we ate for lunch, the capitals of the world, etc. The malfunctioning of this type of memory is one of the most common symptoms found in those suffering from Alzheimer's disease.

A useful model from which to learn about how declarative memory functions is the social transmission of food preference. In other species, this task is connected to the survival of the species and plays a crucial role in their evolution. In this research, the social transmission of food preference was carried out with experimental rats.

When one rodent sniffs another rodent's snout right after the second one has eaten, the first one will later choose to eat the same exact food. Animals learn to remember what their congeners eat and, in that way, lower the risk of eating new foods that could be harmful to them. In addition, they must later use this information acquired during a brief episode of social interaction in very different circumstances. Therefore, they need the flexible expression of memory, which is one of the main traits of declarative memory.

This task depends on learning how to associate smells, a function that is commanded by a specific region of the brain, the nucleus basalis magnocellularis (NBM), which produces acetylcholine (a neurotransmitter that "transfers information" from one neurone to another through synapses). This chemical substance is essential in making the memory work correctly. The nucleus basalis magnocellularis equivalent in humans is the nucleus basalis Meynert. Precisely this is one of the regions of the brain that shown signs of degeneration among those who suffer from Alzheimer's (and who are often treated with drugs that help to produce acetylcholine).

The acetylcholine produced by the nucleus basalis is transferred to other regions of the brain, where it is "recognised" by receptor molecules. The research team examined the possibility of one part of the brain, the prelimbic prefrontal cortex, being linked to the social transmission of food preference. To do so, they applied a chemical compound to the experimental rats that neutralised the acetylcholine receptors (muscarinic cholinergic receptor) of this region. By blocking the receptor, the effect of the neurotransmitter was also neutralised and the changes in the animals' behaviour were observed.

The results demonstrated that the social transmission of food preference was clearly affected after neutralising the acetylcholine receptors. Researchers also verified that the effects were not due to other aspects that could alter the experiment, such as lack of olfactory perception, motivation or social interaction. The results therefore suggest that the prelimbic prefrontal cortex, via the use of acetylcholine, regulates cognitive operations (e.g. flexibility in behaviour, attention or strategic planning) that could be needed to correctly express social transmission of food preference, and therefore necessary for our declarative memory.
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PostPosted: Thu Jul 19, 2007 8:53 am    Post subject: New mechanism found for memory storage in brain Reply with quote

Johns Hopkins Medical Institutions
19 July 2007

New mechanism found for memory storage in brain

Persistent changes in 'slow' nerve currents may also link memory and addiction
Our experiences –the things we see, hear, or do—can trigger long-term changes in the strength of the connections between nerve cells in our brain, and these persistent changes are how the brain encodes information as memory. As reported in Neuron this week, Johns Hopkins researchers have discovered a new biochemical mechanism for memory storage, one that may have a connection with addictive behavior.

Previously, the long-term changes in connection were thought to only involve a fast form of electrical signaling in the brain, electrical blips lasting about one-hundredth of a second. Now, neuroscience professor David Linden, Ph.D., and his colleagues have shown another, much slower form of electrical signaling lasting about a second can also be persistently changed by experience.

They simulated natural brain activity by applying short electrical jolts to slices of rat brain and measuring the current flowing across the cells. After repeated jolting, the strength of the slow nerve signals had dramatically decreased and remained at a low intensity for 30 minutes after electrical jolts ceased.

These slow signals are produced by a nerve cell receptor called mGluR1, which has been associated with behaviors such as addiction and epilepsy. “Both of these conditions also involve long-term changes in the function of nerve connections,” says Linden. “So in addition to furthering our basic understanding of memory storage, our work suggests that drugs designed to alter mGluR1 are promising candidates for the treatment of addiction, epilepsy, and diseases of memory.”


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The research was funded by the Republic of Korea Ministry of Health and Welfare and the National Institutes of Health

Authors on the paper are Paul Worley and Linden of Johns Hopkins and Sang Jeong Kim, Yunju Jin and Jun Kim of Seoul National University College of Medicine

On the Web:
http://neuroscience.jhu.edu/DavidLinden.php
www.neuron.org
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PostPosted: Thu Jul 26, 2007 1:30 pm    Post subject: New protein synthesis not essential to memory formation Reply with quote

New protein synthesis not essential to memory formation

Diana Yates, Life Sciences Editor

Released 7/26/07


CHAMPAIGN, Ill. — New research from the University of Illinois challenges the premise that the brain must build new proteins in response to an experience for that experience to be recorded in long-term memory.

The findings, published in the Proceedings of the National Academy of Sciences, could alter basic assumptions about the role of protein synthesis in memory formation.

Brain researchers have long used drugs that enhance or hinder memory formation to gain insight into the mechanisms at play. Early experiments in rats found that protein synthesis inhibitors injected into brain regions involved in memory processing could disrupt long-term memory formation. This led some to hypothesize that new protein synthesis was essential to the creation of long-term memories.

A research team led by neuroscientist Paul E. Gold discovered an alternate explanation for this effect. The researchers observed that the protein synthesis inhibitor anisomycin, which is commonly used in memory studies, causes dramatic changes in brain chemistry – apart from protein synthesis inhibition – that interfere with memory formation. They found that exposing rat brains to anisomycin sets off wild fluctuations in neurotransmitter levels in the brain region targeted in the experiment – the amygdala, one of several brain structures involved in processing memories and emotions. Large fluctuations in neurotransmitter levels in the amygdala are known to interfere with memory formation.

The researchers were surprised by the intensity of the brain’s response to anisomycin. Shortly after they injected the drug into the rat amygdala, they saw huge increases – from 1,000 to 17,000 percent – in levels of the neurotransmitters norepinephrine, dopamine and serotonin.

“This is far above anything we’ve seen physiologically in any experiment,” Gold said. “Normally you think of a 200 percent increase as a really solid result and 300 percent as outrageously high. I wouldn’t have thought that there was that much (neurotransmitter) to be released.”

Shortly after this spike, dopamine and norepinephrine levels plummeted, dropping well below baseline for up to 48 hours after the initial exposure to anisomycin.

As expected, the rats exposed to anisomycin prior to training had impaired long-term recall of the events. To determine whether the inability to form lasting memories was caused by the anisomycin or by changes in neurotransmitter levels, the researchers repeated the experiment, adding drugs designed to counter the fluctuations in neurotransmitter levels. When the neurotransmitter imbalances were neutralized or blunted – even in the presence of anisomycin – memory formation was significantly restored.

“If we block anisomycin’s effects on the neurotransmitters, then we block many of its effects on memory,” Gold said. “We still have the protein synthesis inhibition, but it no longer causes the (same level of) amnesia.”

It is possible that some of the amnesia is due to the cessation of protein synthesis, Gold said. But, he said, the evidence suggests otherwise. “I think the protein synthesis inhibition itself is causing cells to act in unusual ways,” he said.

“No one would deny that protein synthesis is needed to maintain normal brain functions, including memory,” Gold said. “But the idea that new protein synthesis is required to make long-lasting memories should be reexamined.”

Gold is a professor of psychology and psychiatry and is affiliated with the neuroscience program and the Institute for Genomic Biology.
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