A new study finds that the inevitable cognitive decline we all face starts earlier than we originally thought. Christie Nicholson reports.

The witness points out the criminal in a police lineup. She swears she'd remember that face forever. Then DNA evidence shows she's got the wrong guy. It happens so frequently that many courts are looking with extreme skepticism at eyewitness testimony.

Is there a way to get a more accurate reading of memory? A new study says yes. "Eye movements are drawn quickly to remembered objects," says Deborah Hannula, assistant professor at the University of Wisconsin Milwaukee, who conducted the study with Carol L. Baym and Neal J. Cohen of the University of Illinois, Urbana-Champaign and David E. Warren of the University of Iowa College of Medicine. Tracking where and for how long a person focuses his or her eyes "can distinguish previously seen from novel materials even when behavioral reports fail to do so." The findings will appear in an upcoming issue of Psychological Science, a journal published by the Association for Psychological Science.

The researchers gave university students 36 faces to study. These target faces were also morphed to produce images closely resembling them; the morphed phases were not seen during the study phase. The students were then shown 36 three-face displays, one at a time. Told that the studied faces wouldn't always be there, the participants had to press a button indicating which face was the studied one, or simply choose a face if they felt none had been studied. They then reported verbally whether the studied target face was present or not. While they looked at the 3-face display, their eye movements were recorded, tracking where the eyes focused first and what proportion of time was spent looking there. For the analysis, the psychologists divided the faces into three groups: studied targets; morphs mistaken for the "target" face; and morphs chosen and known to be incorrect.

Participants easily identified the target faces most of the time. They also spent more time looking at these faces, and did so soon after the 3-face display had been presented. "The really interesting finding is that before they chose a face and pressed a button, there was disproportionate viewing of the target faces as compared to either type of selected face," said Hannula. However, "after the response was made, viewing tended to mimic the behavioral endorsement of a face as studied or not, whether that endorsement was correct or incorrect." In other words, "pre-response viewing seems to reflect actual experience, and post-response viewing seems to reflect the decision making process and whether or not the face will be endorsed as studied."

Hannula theorizes as to what is happening: "Early disproportionate viewing of the target face may precede and help give rise to awareness that a particular face has been studied. Subsequently, we begin to think about the choice that we're making"—we look closely, compare and weigh the options—"these cognitive processes permit us to make a decision, but may also lead us down the wrong path. In this case, leading us to endorse a face as studied despite having never seen it before." Aside from the potential for practical application, says Hannula, eye movement methods could be used to examine memory in individuals—like some psychiatric patients and children – who may have trouble communicating what it is that they remember. "Eye movements might provide us with more information about what exactly these individuals remember than behavioral reports alone."

Human minds have hit an evolutionary "sweet spot" and - unlike computers - cannot continually get smarter without trade-offs elsewhere, according to research by the University of Warwick. Researchers asked the question why we are not more intelligent than we are given the adaptive evolutionary process. Their conclusions show that you can have too much of a good thing when it comes to mental performance. The evidence suggests that for every gain in cognitive functions, for example better memory, increased attention or improved intelligence, there is a price to pay elsewhere - meaning a highly-evolved "supermind" is the stuff of science fiction.

University of Warwick psychology researcher Thomas Hills and Ralph Hertwig of the University of Basel looked at a range of studies, including research into the use of drugs like Ritalan which help with attention, studies of people with autism as well as a study of the Ashkenazi Jewish population. For instance, among individuals with enhanced cognitive abilities- such as savants, people with photographic memories, and even genetically segregated populations of individuals with above average IQ, these individuals often suffer from related disorders, such as autism, debilitating synaesthesia and neural disorders linked with enhanced brain growth.

Similarly, drugs like Ritalan only help people with lower attention spans whereas people who don't have trouble focusing can actually perform worse when they take attention-enhancing drugs. Dr Hills said: "These kinds of studies suggest there is an upper limit to how much people can or should improve their mental functions like attention, memory or intelligence. Take a complex task like driving, where the mind needs to be dynamically focused, attending to the right things such as the road ahead and other road users – which are changing all the time. If you enhance your ability to focus too much, and end up over-focusing on specific details, like the driver trying to hide in your blind spot, then you may fail to see another driver suddenly veering into your lane from the other direction. Or if you drink coffee to make yourself more alert, the trade-off is that it is likely to increase your anxiety levels and lose your fine motor control. There are always trade-offs. In other words, there is a 'sweet spot' in terms of enhancing our mental abilities – if you go beyond that spot - just like in the fairy-tales - you have to pay the price."

A cognitive map enables orientation

The cerebellum is far more intensively involved in helping us navigate than previously thought. To move and learn effectively in spatial environments our brain, and particularly our hippocampus, creates a "cognitive" map of the environment. The cerebellum contributes to the creation of this map through altering the chemical communication between its neurones. If this ability is inactivated, the brain is no longer able to to create an effective spatial representation and thus navigation in an environment becomes impaired. The details of these observations were recently published in Science by the Ruhr University neuroscientist, Marion André who is a student of the International Graduate School of Neuroscience( IGSN), along with her colleagues in France.

A cognitive map in the hippocampus
In order to navigate efficiently in an environment, we need to create and maintain a reliable internal representation of the external world. A key region enabling such representation is the hippocampus which contains specialized pyramidal neurons named place cells. Each place cell is activated at specific location of the environment and gives dynamic information about self-location relative to the external world. These neurons thus generate a cognitive map in the hippocampal system through the integration of multi sensory inputs combining external information (such as visual, auditory, olfactory and tactile cues) and inputs generated by self-motion (i.e. optic flow, proprioceptive and vestibular information).

Decisive: synaptic plasticity
Our ability to navigate also relies on the potential to use this cognitive map to form an optimal trajectory toward a goal. The cerebellum, a foliate region based at the back of the brain, has been recently shown to participate in the formation of the optimal trajectory. This structure contains neurons that are able to increase or decrease their chemical communication, a mechanism called synaptic plasticity. A decrease in the synaptic transmission of the cerebellar neurons, named long-term depression (LTD) participates in the optimization of the path toward a goal.

No orientation without LTD
Using transgenic mice that had a mutation impairing exclusively LTD of the cerebellar neurons, the neuroscientists were able to show that the cerebellum participates also in the formation of the hippocampal cognitive map. Indeed mice lacking this form of cerebellar plasticity were unable to build a reliable cognitive representation of the environment when they had to use self-motion information. Consequently, they were unable to navigate efficiently towards a goal in the absence of external information (for instance in the dark). This work highlights for the first time an unsuspected function of the cerebellum in shaping the representation of our body in space.

The witness points out the criminal in a police lineup. She swears she'd remember that face forever. Then DNA evidence shows she's got the wrong guy. It happens so frequently that many courts are looking with extreme skepticism at eyewitness testimony.

Is there a way to get a more accurate reading of memory? A new study says yes. "Eye movements are drawn quickly to remembered objects," says Deborah Hannula, assistant professor at the University of Wisconsin Milwaukee, who conducted the study with Carol L. Baym and Neal J. Cohen of the University of Illinois, Urbana-Champaign and David E. Warren of the University of Iowa College of Medicine. Tracking where and for how long a person focuses his or her eyes "can distinguish previously seen from novel materials even when behavioral reports fail to do so." The findings will appear in an upcoming issue of Psychological Science, a journal published by the Association for Psychological Science.

The researchers gave university students 36 faces to study. These target faces were also morphed to produce images closely resembling them; the morphed phases were not seen during the study phase. The students were then shown 36 three-face displays, one at a time. Told that the studied faces wouldn't always be there, the participants had to press a button indicating which face was the studied one, or simply choose a face if they felt none had been studied. They then reported verbally whether the studied target face was present or not. While they looked at the 3-face display, their eye movements were recorded, tracking where the eyes focused first and what proportion of time was spent looking there. For the analysis, the psychologists divided the faces into three groups: studied targets; morphs mistaken for the "target" face; and morphs chosen and known to be incorrect.

Participants easily identified the target faces most of the time. They also spent more time looking at these faces, and did so soon after the 3-face display had been presented. "The really interesting finding is that before they chose a face and pressed a button, there was disproportionate viewing of the target faces as compared to either type of selected face," said Hannula. However, "after the response was made, viewing tended to mimic the behavioral endorsement of a face as studied or not, whether that endorsement was correct or incorrect." In other words, "pre-response viewing seems to reflect actual experience, and post-response viewing seems to reflect the decision making process and whether or not the face will be endorsed as studied."

Hannula theorizes as to what is happening: "Early disproportionate viewing of the target face may precede and help give rise to awareness that a particular face has been studied. Subsequently, we begin to think about the choice that we're making"—we look closely, compare and weigh the options—"these cognitive processes permit us to make a decision, but may also lead us down the wrong path. In this case, leading us to endorse a face as studied despite having never seen it before." Aside from the potential for practical application, says Hannula, eye movement methods could be used to examine memory in individuals—like some psychiatric patients and children – who may have trouble communicating what it is that they remember. "Eye movements might provide us with more information about what exactly these individuals remember than behavioral reports alone."

As we get older, our cognitive abilities change, improving when we're younger and declining as we age. Scientists posit a hierarchical structure within which these abilities are organized. There's the "lowest" level -- measured by specific tests, such as story memory or word memory; the second level, which groups various skills involved in a category of cognitive ability, such as memory, perceptual speed, or reasoning; and finally, the "general," or G, factor, a sort of statistical aggregate of all the thinking abilities.

What happens to this structure as we age? That was the question Timothy A. Salthouse, Brown-Forman professor of psychology at the University of Virginia, investigated in a new study appearing in an upcoming issue of Psychological Science, a journal published by the Association for Psychological Science. His findings advance psychologists' understanding of the complexities of the aging brain.

"There are three hypotheses about how this works," says Salthouse. "One is that abilities become more strongly integrated with one another as we age." That theory suggests the general factor influences cognitive aging the most. The second -- based on the idea that connectivity among different brain regions lessens with age -- "is almost the opposite: that the changes in cognitive abilities become more rather than less independent with age." The third was Salthouse's hypothesis: The structure remains constant throughout the aging process.

Using a sample of 1,490 healthy adults ages 18 to 89, Salthouse performed analyses of the scores on 16 tests of five cognitive abilities -- vocabulary, reasoning, spatial relations, memory, and perceptual speed. The primary analyses were on the changes in the test scores across an interval of about two and a half years.

The findings confirmed Salthouse's hunch: "The effects of aging on memory, on reasoning, on spatial relations, and so on are not necessarily constant. But the structure within which these changes are occurring does not seem to change as a function of age." In normal, healthy people, "the direction and magnitude of change may be different" when we're 18 or 88, he says. "But it appears that the qualitative nature of cognitive change remains the same throughout adulthood."

The study could inform other research investigating "what allows some people to age more gracefully than others," says Salthouse. That is, do people who stay mentally sharper maintain their ability structures better than those who become more forgetful or less agile at reasoning? And in the future, applying what we know about the structures of change could enhance "interventions that we think will improve cognitive functioning" at any age or stage of life.

The hippocampus is a brain structure that plays a major role in the process of memory formation. It is not entirely clear how the hippocampus manages to string together events that are part of the same experience but are separated by "empty" periods of time. Now, new research published by Cell Press in the August 25 issue of the journal Neuron finds that there are neurons in the hippocampus that encode every sequential moment in a series of events that compose a discrete experience.

"The hippocampus is critical for remembering the flow of events in distinct experiences and, in doing so, bridges gaps between events that are separated by periods of time," explains senior study author, Dr. Howard Eichenbaum from the Center for Memory and Brain at Boston University. "We were interested in investigating how hippocampal neurons represent the temporal organization of extended experience and, more specifically, how they bridge the gaps between events that are discontiguous, that is, they do not occur in an immediate sequence."

Dr. Eichenbaum and colleagues developed an innovative task that required rats to distinguish sequences of two events that were separated by a time delay. The task required the rats to remember the initial event in order to respond appropriately to the second event and receive a reward. The researchers recorded hippocampal neural activity as the rats completed the tasks. "Our paradigm provided the opportunity to examine whether hippocampal neurons encode sequential events and to explore how the activity of hippocampal neurons bridges and disambiguates an identical empty delay in time between events in the task sequence," explains Dr. Eichenbaum.

The researchers observed that activity in the hippocampus robustly represented sequential memories and that certain cells became activated at successive moments during the empty gap that occurred between the two events. "Each cell by itself provided a detailed 'snapshot' of the experience, and only at specific moments. But together, the activity from all of the cells filled in the gap," said coauthor Dr. Christopher MacDonald. The appropriately named "time cells" that were active have much in common with previously described "place cells" that are active when animals are at particular locations in space. The time cells were able to adjust, or "retime," when the duration of the delay period was altered.

Importantly, the activity of hippocampal neurons also signaled the timing of key events in the sequences and could differentiate between the different types of sequences. "Our findings suggest that hippocampal neurons segment temporally organized memories much the same as they represent locations of important events in spatially defined environments," concludes Dr. Eichenbaum. "Place cells and time cells may reflect fundamental mechanisms by which hippocampal neurons parse any spatiotemporal context into discrete units of where and when important events occur."

How easy is it to falsify memory? New research at the Weizmann Institute shows that a bit of social pressure may be all that is needed. The study, which appears Friday in Science, reveals a unique pattern of brain activity when false memories are formed – one that hints at a surprising connection between our social selves and memory.

The experiment, conducted by Prof. Yadin Dudai and research student Micah Edelson of the Institute's Neurobiology Department with Prof. Raymond Dolan and Dr. Tali Sharot of University College London, took place in four stages. In the first, volunteers watched a documentary film in small groups. Three days later, they returned to the lab individually to take a memory test, answering questions about the film. They were also asked how confident they were in their answers.

They were later invited back to the lab to retake the test while being scanned in a functional MRI (fMRI) that revealed their brain activity. This time, the subjects were also given a "lifeline": the supposed answers of the others in their film viewing group (along with social-media-style photos). Planted among these were false answers to questions the volunteers had previously answered correctly and confidently. The participants conformed to the group on these "planted" responses, giving incorrect answers nearly 70% of the time.

But were they simply conforming to perceived social demands, or had their memory of the film actually undergone a change? To find out, the researchers invited the subjects back to the lab to take the memory test once again, telling them that the answers they had previously been fed were not those of their fellow film watchers, but random computer generations. Some of the responses reverted back to the original, correct ones, but close to half remained erroneous, implying that the subjects were relying on false memories implanted in the earlier session.

An analysis of the fMRI data showed differences in brain activity between the persistent false memories and the temporary errors of social compliance. The most outstanding feature of the false memories was a strong co-activation and connectivity between two brain areas: the hippocampus and the amygdala. The hippocampus is known to play a role in long-term memory formation, while the amygdala, sometimes known as the emotion center of the brain, plays a role in social interaction. The scientists think that the amygdala may act as a gateway connecting the social and memory processing parts of our brain; its "stamp" may be needed for some types of memories, giving them approval to be uploaded to the memory banks. Thus social reinforcement could act on the amygdala to persuade our brains to replace a strong memory with a false one.

To view the video accompanying this press release, visit The Weizmann Institute of Science YouTube Channel (http://www.youtube.com/user/WeizmannInstitute#p/u/0/bKCCYhHUTPE)

The 2010 American Association for the Advancement of Science (AAAS) Scientific Freedom and Responsibility Award will honor "false memory" investigator Dr. Elizabeth Loftus of the University of California, Irvine. Dr. Loftus is "an ideal example of a scientist who is distinguished for both advancing science and applying it to make critical contributions to society," the association said. Specifically, she was honored "for the profound impact that her pioneering research on human memory has had on the administration of justice in the United States and abroad," the award committee said.

Dr. Loftus, who serves as Distinguished Professor of Social Ecology, and Professor of Law, and Cognitive Science at UC Irvine, demonstrated that memories can be implanted or manipulated by a variety of means," the committee noted. Her early research explored the basic functions of memory, such as how the mind classifies and remembers information. Later, she studied eyewitness accounts of crimes and concluded that, rather than being fixed, memories are fragile, suggestible, and malleable over time. For example, she discovered that people remember things differently, depending on how they are asked a question.

Dr. Loftus has testified at more than 200 civil and criminal trials. Such testimony has often been controversial. But her work has been vindicated by the finding that, of the more than 250 prisoners freed on the basis of subsequent DNA analysis, the most common reason for wrongful convictions was faulty eyewitness testimony.

Her discovery that memories can be implanted or manipulated led her to identify what has been called "False Memory Syndrome," in which people in psychotherapy "remember" something they had long ago forgotten or "repressed," such as sexual abuse. In several states, the AAAS award committee noted, judges have now dismissed murder charges if there was no evidence to corroborate a repressed memory.

Despite the inherently controversial nature of her work, Dr. Loftus has earned important supporters. For example, Dr. Daniel Schacter, former head of the psychology department at Harvard University, has described her as "a pioneer motivated by principle," and the American Psychiatric Association has declared repressed memory treatment "dead" because of her research. She was elected to the membership of the National Academy of Sciences, and she has received numerous awards, including one from the American Academy of Forensic Sciences. She was named one of the 100 most influential psychologists of the 20th century—the top-ranked woman on the list.

Dr. Loftus earned her B.A. degree with highest honors in mathematics and psychology from the University of California at Los Angeles in 1966. She received a Master's degree and a Ph.D. degree in Psychology from Stanford University in 1967 and 1970, respectively.

The Scientific Freedom and Responsibility Award is presented annually by American Association for the Advancement of Science to honor individual scientists and engineers or organizations for exemplary actions that help foster scientific freedom and responsibility. The award recognizes outstanding efforts to protect the public's health, safety or welfare; to focus public attention on potential impacts of science and technology; to establish new precedents in carrying out social responsibilities; or to defend the professional freedom of scientists and engineers.

The award was established in 1980 and is approved by the AAAS Board of Directors. The AAAS Scientific Freedom and Responsibility Award will be presented at the 177th AAAS Annual Meeting in Washington, D.C., which will take place 17-21 February 2011. The awards ceremony and reception will be held in the Grand Ballroom North, Washington Renaissance Downtown, on Saturday, 19 February at 6:00 p.m.

Congratulations, Dr. Loftus!

Sleeping brain "calculates" what to remember and what to forget, study says.

Read the article from National Geographic here.

As humans, we spend about a third of our lives asleep. So there must be a point to it, right? Scientists have found that sleep helps consolidate memories, fixing them in the brain so we can retrieve them later. Now, new research is showing that sleep also seems to reorganize memories, picking out the emotional details and reconfiguring the memories to help you produce new and creative ideas, according to the authors of an article in Current Directions in Psychological Science, a journal of the Association for Psychological Science.

"Sleep is making memories stronger," says Jessica D. Payne of the University of Notre Dame, who cowrote the review with Elizabeth A. Kensinger of Boston College. "It also seems to be doing something which I think is so much more interesting, and that is reorganizing and restructuring memories."

Payne and Kensinger study what happens to memories during sleep, and they have found that a person tends to hang on to the most emotional part of a memory. For example, if someone is shown a scene with an emotional object, such as a wrecked car, in the foreground, they're more likely to remember the emotional object than, say, the palm trees in the background—particularly if they're tested after a night of sleep. They have also measured brain activity during sleep and found that regions of the brain involved with emotion and memory consolidation are active.

"In our fast-paced society, one of the first things to go is our sleep," Payne says. "I think that's based on a profound misunderstanding that the sleeping brain isn't doing anything." The brain is busy. It's not just consolidating memories, it's organizing them and picking out the most salient information. She thinks this is what makes it possible for people to come up with creative, new ideas.

Payne has taken the research to heart. "I give myself an eight-hour sleep opportunity every night. I never used to do that—until I started seeing my data," she says. People who say they'll sleep when they're dead are sacrificing their ability to have good thoughts now, she says. "We can get away with less sleep, but it has a profound effect on our cognitive abilities."

Did I turn off the stove, or did I just imagine it? Memory isn't always reliable. Psychological scientists have discovered all sorts of ways that false memories get created, and now there's another one for the list: watching someone else do an action can make you think you did it yourself.

The team of psychological scientists who found the new way to create false memories weren't setting out to make a big discovery. They were trying to learn more about imagination, another way that false memories get created. But then in an experiment, they found that people who had watched a video of someone else doing a simple action—shaking a bottle or shuffling a deck of cards, for example—often remembered doing the action themselves two weeks later.

"We were stunned," says Gerald Echterhoff, of Jacobs University Bremen. He cowrote the study with Isabel Lindner of the University of Cologne, Patrick S.R. Davidson of the University of Ottawa, and Matthias Brand of the University of Duisburg-Essen. They changed course to examine this phenomenon more closely with a series of experiments.

In each experiment, participants performed several simple actions. Then they watched videos of someone else doing simple actions—some of which they had already performed, and some of which they had not. Two weeks later, they were asked which actions they had done. They were much more likely to falsely remember doing an action if they had watched someone else do it. This happened even when participants were told about the effect and warned that it could happen to them. The results are published in Psychological Science, a journal of the Association for Psychological Science.

Echterhoff says you shouldn't worry that this happens all the time—but it's worth remembering that your memory isn't always reliable. "It's good to have an informed doubt or informed skepticism about your memory performance, so you don't just easily trust whatever comes to your mind as true and for granted."

He thinks the mechanism may have something to do with internal simulation of what other people are doing while we are observing them. Intriguingly, if simulation was the mechanism, it would occur spontaneously and without our awareness. To speculate further, this simulation could involve brain structures like the 'mirror neuron system,' which seems to be involved both in performing actions ourselves as well as in observing other people's actions. Simulation is good when it helps you predict someone's next action, or to learn how to do things, but this could be an unfortunate side effect.

The theory of repressed memory is "the most pernicious bit of folklore ever to infect psychology and psychiatry."

Our memories are strengthened during periods of rest while we are awake, researchers at New York University have found. The findings, which appear in the latest issue of the journal Neuron, expand our understanding of how memories are boosted—previous studies had shown this process occurs during sleep, but not during times of awake rest.

"Taking a coffee break after class can actually help you retain that information you just learned," explained Lila Davachi, an assistant professor in NYU's Department of Psychology and Center for Neural Science, in whose laboratory the study was conducted. "Your brain wants you to tune out other tasks so you can tune in to what you just learned."

The study, whose lead author was Arielle Tambini, a doctoral candidate in NYU's Graduate School of Arts and Science, focused on memory consolidation—the period when a memory is stabilized after it is initially created, or encoded. To determine if memory consolidation occurred during periods of awake rest, the researchers imaged the hippocampus, a brain structure known to play a significant role in memory, and cortical regions during periods of awake rest. Previous studies have demonstrated regions of the brain more active during periods of rest, but their function at these times had been unclear.

The NYU experiment tested subjects' associative memory by showing them pairs of images containing a human face and an object (e.g., a beach ball) or a human face and a scene (e.g., a beach) followed by periods of awake rest. Subjects were not informed their memory for these images would later be tested, but, rather, were instructed to rest and simply think about anything that they wanted, but to remain awake during the resting periods. The researchers used functional magnetic resonance imaging (fMRI) to gauge activity in the hippocampus and cortical regions during the task and during the ensuing rest period.

The experiment yielded two noteworthy results. First, the researchers found that during rest after the study experience (after the visuals were shown), there was a significant correlation between brain activity in the subjects' hippocampus and cortical regions that were active during the initial encoding of each stimulus pair. However, this boost in brain correlations was only seen following experiences that were later memorable suggesting these parts of the brain act in tandem for a purpose — to consolidate memories during rest. Second, when examining each subject individually, it was found that subjects who had greater resting correlations between the hippocampus and cortex, also exhibited better performance on a subsequent associative memory test and those whose brain correlations were weaker, had worse memory — in other words, the greater the activity in hippocampus and cortical regions, the stronger the memory.

"Your brain is working for you when you're resting, so rest is important for memory and cognitive function," Davachi observed. "This is something we don't appreciate much, especially when today's information technologies keep us working round-the-clock."

Brain activity during event, failed recollection similar

A woman looks familiar, but you can't remember her name or where you met her. New research by UC Irvine neuroscientists suggests the memory exists - you simply can't retrieve it. Using advanced brain imaging techniques, the scientists discovered that a person's brain activity while remembering an event is very similar to when it was first experienced, even if specifics can't be recalled. "If the details are still there, hopefully we can find a way to access them," said Jeff Johnson, postdoctoral researcher at UCI's Center for the Neurobiology of Learning & Memory and lead author of the study, appearing Sept. 10 in the journal Neuron. "By understanding how this works in young, healthy adults, we can potentially gain insight into situations where our memories fail more noticeably, such as when we get older," he said. "It also might shed light on the fate of vivid memories of traumatic events that we may want to forget."

In collaboration with scientists at Princeton University, Johnson and colleague Michael Rugg, CNLM director, used functional magnetic resonance imaging to study the brain activity of students. Inside an fMRI scanner, the students were shown words and asked to perform various tasks: imagine how an artist would draw the object named by the word, think about how the object is used, or pronounce the word backward in their minds. The scanner captured images of their brain activity during these exercises. About 20 minutes later, the students viewed the words a second time and were asked to remember any details linked to them. Again, brain activity was recorded.

Utilizing a mathematical method called pattern analysis, the scientists associated the different tasks with distinct patterns of brain activity. When a student had a strong recollection of a word from a particular task, the pattern was very similar to the one generated during the task. When recollection was weak or nonexistent, the pattern was not as prominent but still recognizable as belonging to that particular task. "The pattern analyzer could accurately identify tasks based on the patterns generated, regardless of whether the subject remembered specific details," Johnson said. "This tells us the brain knew something about what had occurred, even though the subject was not aware of the information."

Eyewitness testimony is a crucial part of many criminal trials even though research increasingly suggests that it may not be as accurate as we (and many lawyers) would like it to be. For example, if you witness a man in a blue sweater stealing something, then overhear people talking about a gray shirt, how likely are you to remember the real color of the thief's sweater? Studies have shown that when people are told false information about an event, they become less likely to remember what actually happened - it is easy to mix up the real facts with fake ones. However, there is evidence that when people are forced to recall what they witnessed (shortly after the event), they are more likely to remember details of what really happened.

Psychologists Jason Chan of Iowa State University, Ayanna Thomas from Tufts University and John Bulevich from Rhode Island College wanted to see how providing false information following a recall test would affect volunteers' memories of an event that they witnessed. A group of volunteers watched the first episode of "24" and then either took an immediate recall test about the show or played a game. Next, all of the subjects were told false information about the episode they had seen and then took a final memory test about the show.

The results, reported in the January issue of Psychological Science, a journal of the Association for Psychological Science, were surprising. The researchers found that the volunteers who took the test immediately after watching the show were almost twice as likely to recall false information compared to the volunteers who played the game following the episode.

The results of a follow-up experiment suggest that the first recall test may have improved subjects' ability to learn the false information - that is, the first test enhanced learning of new and erroneous information. These findings show that recently recalled information is prone to distortion. The authors conclude that "this study shows that even psychologists may have underestimated the malleability of eyewitness testimony."

To Get Good Grades, Get Good Sleep.

You’d think that college students would be experts at sleeping.  But odd hours, parties, cramming for tests, personal problems, self-medication with drugs or alcohol and general  can wreck a student’s sleep habits. Which can be bad for the body and the mind.

60-Second Psych from Scientific American podcasts
8 December 2008

Maybe you have an 85-year-old grandfather who still whips through the newspaper crossword puzzle every morning or a 94-year-old aunt who never forgets a name or a face. They don't seem to suffer the ravages of memory that beset most people as they age. Researchers at Northwestern University's Feinberg School of Medicine wondered if the brains of the elderly with still laser sharp memory -- called "super aged" -- were somehow different than everyone else's. So, instead of the usual approach in which scientists explore what goes wrong in a brain when older people lose their memory, they investigated what goes right in an aging brain that stays nimble.

Now they have a preliminary answer. Scientists examined the brains of five deceased people considered super aged because of their high performance on memory tests when they were more than 80 years old and compared them to the brains of elderly, non-demented individuals. Researchers found the super aged brains had many fewer fiber-like tangles than the brains of those who had aged normally. The tangles consist of a protein called tau that accumulates inside brain cells and is thought to eventually kill the cells. Tangles are found in moderate numbers in the brains of elderly and increase substantially in the brains of Alzheimer's disease patients.

"This new finding in super aged brains is very exciting," said Changiz Geula, principal investigator of the study and a research professor of neurology at the Cognitive Neurology and Alzheimer's Disease Center at Northwestern's Feinberg School. "It was always assumed that the accumulation of these tangles is a progressive phenomenon through the aging process. But we are seeing that some individuals are immune to tangle formation and that the presence of these tangles seems to influence cognitive performance." Individuals who have few tangles perform at superior levels, while those who have more tangles appear to be normal for their age, Geula noted. Geula will present his findings Sunday, November 16, at the Society for Neuroscience annual meeting in Washington, D.C.

The number of plaques in the brains of the super aged was similar to that in the brains of the normally aging group. The plaque is an aggregation of protein called amyloid that becomes deposited outside the brain cell and disrupts communication between neurons. Like tangles, plaques also are found in modest numbers in the brains of aged individuals and show a dramatic increase in number in Alzheimer's disease. Geula said the lower number of tangles in the super aged appears to be the critical difference in maintaining memory skills.

Some of the super aged in the study performed memory tasks at the level of people who were about 50 years old. For example, after being told a story, they were able to remember it immediately after and still accurately recall its details 30 minutes later. They also remembered a list of 15 words and recalled these words equally well when tested after 30 minutes.

Geula said new research will focus on what makes cells in super aged brains more resistant to tangle formation. "We want to see what protects the brains of these individuals against the ravages that cause memory loss," he said. " Understanding the specific genetic and molecular characteristics of the brains that makes them resistant, someday may lead to the ability to protect average brains from memory loss. "

Geula's research is part of a larger super aging study at Northwestern's Cognitive Neurology and Alzheimer's Disease Center (CNADC). The study's goal is to identify high functioning individuals over 80 and investigate what factors are important to maintain this ability into old age. A number of super aged individuals have been identified and are being followed up annually with tests of cognitive abilities. Recruitment continues for the study.

Do you know someone who claims to remember their first day of kindergarten? Or a trip they took as a toddler? While some people may be able to recall trivial details from the past, laboratory research shows that the human memory can be remarkably fragile and even inventive. In fact, people can easily create false memories of their past and a new study shows that such memories can have long-term effects on our behavior.

Psychologists Elke Geraerts of the University of St. Andrews and Maastricht University, Daniel Bernstein of Kwantlen Polytechnic University and the University of Washington, Harald Merckelbach, Christel Linders, and Linsey Raymaekers of Maastricht University, and Elizabeth F. Loftus of University of California, Irvine, found that it is possible to change long-term behaviors using a simple suggestive technique.

In a series of experiments, the researchers falsely suggested that participants had become ill after eating egg salad as a child. Afterwards, the researchers offered different kinds of sandwiches to the participants, including ones with an egg salad filling. Four months later, the participants were asked to be in a separate study in which they evaluated egg salad as well as other foods. They were then given the same kinds of sandwiches that had been offered to them four months earlier.

Interestingly, participants who were told they had become ill as a child after eating egg salad showed a distinct change in attitudes and behavior towards this food after the experiment. They not only gave the food lower evaluations than participants who did not develop false memories or were in the control group, but they also avoided egg salad sandwiches more than any of the other participants four months later.

The results, appearing in the August issue of Psychological Science, a journal of the Association for Psychological Science, "clearly demonstrate that false suggestions about childhood events can profoundly change people's attitudes and behavior," wrote the authors.

These findings have significant implications for the authenticity of reports of recovered memory experiences. While previous research indicates that spontaneously recovered memories may reflect real memories of abuse, there is no such evidence for abuse memories recovered through suggestive therapy. The results might also influence obesity treatments and dieting choices. The authors suggest that it may be possible for people to learn to avoid certain foods by believing they had negative experiences with the food as a child. Overall, this study clearly demonstrates that false suggestions about childhood events can profoundly change people's attitudes and behavior.

A period of slumber helps the brain distinguish core emotions from background details

As poets, songwriters and authors have described, our memories range from misty water-colored recollections to vividly detailed images of the times of our lives. Now, a study led by researchers at Beth Israel Deaconess Medical Center (BIDMC) and Boston College offers new insights into the specific components of emotional memories, suggesting that sleep plays a key role in determining what we remember – and what we forget.

Reported in the August 2008 issue of the journal Psychological Science, the findings show that a period of slumber helps the brain to selectively preserve and enhance those aspects of a memory that are of greatest emotional resonance, while at the same time diminishing the memory's neutral background details. "This tells us that sleep's role in emotional memory preservation is more than just mechanistic," says the study's first author Jessica Payne, PhD, a Harvard University research fellow in the Division of Psychiatry at BIDMC. "In order to preserve what it deems most important, the brain makes a tradeoff, strengthening the memory's emotional core and obscuring its neutral background."

Previous studies have established the key role that sleep plays in procedural memory, demonstrating that the consolidation of procedural skills (such as typing or playing the piano) is greatly enhanced following a period of sleep. But sleep's importance in the development of episodic memories – in particular, those with emotional resonance– has been less clear.

"Emotional memories usually contain highly charged elements – for example, the car that sideswiped us on the ride home – along with other elements that are only tangentially related to the emotion, such as the name of the street we were traveling on or what store we'd just passed," explains study author Elizabeth Kensinger, PhD, an Assistant Professor in the College of Arts and Sciences at Boston College. "We were interested in examining whether sleep would affect memory for all of these elements equally, or whether sleep might allow some of the event features to decay at a faster rate than others."

The authors tested 88 college students. Study participants were shown scenes that depicted either neutral subjects on a neutral background (a car parked on a street in front of shops) or negatively arousing subjects on a neutral background (a badly crashed car parked on a similar street). The participants were then tested separately on their memories of both the central objects in the pictures and the backgrounds in the scenes. In this way, memory could be compared for the emotional aspects of a scene (the crashed car) versus the non-emotional aspects of the scene (the street on which the car had crashed.)

Subjects were divided into three groups. The first group underwent memory testing after 12 hours spent awake during the daytime; the second group was tested after 12 nighttime hours, including their normal period of nighttime sleep; and the third baseline group was tested 30 minutes after viewing the images, in either the morning or evening.

"Our results revealed that the study subjects who stayed awake all day largely forgot the entire negative scene [they had seen], with their memories of both the central objects and the backgrounds decaying at similar rates," says Payne. But, she adds, among the individuals who were tested after a period of sleep, memory recall for the central negative objects (i.e. the smashed car) was preserved in detail.

"After an evening of sleep, the subjects remembered the emotional items [smashed car] as accurately as the subjects whose memories had been tested only 30 minutes after looking at the scenes," explains Kensinger. "By contrast, sleep did little to preserve memory for the backgrounds [i.e. street scenes] and so memory for those elements reached a comparably low level after a night of sleep as it did after a day spent awake."

"This is consistent with the possibility that the individual components of emotional memory become 'unbound' during sleep," adds Payne, explaining that "unbinding" enables the sleeping brain to selectively preserve only that information which it calculates to be most salient and worthy of remembering. A real-world example of this tradeoff, she adds, is the "weapon focus effect" in which crime victims vividly remember an assailant's weapon, but have little memory for other important aspects of the crime scene. Traumatic memories, such as the flashbacks experienced among individuals with post-traumatic stress disorder, can demonstrate similar disparities, with some aspects of an experience seemingly engraved in memory while other details are erased.

"Sleep is a smart, sophisticated process," adds Payne. "You might say that sleep is actually working at night to decide what memories to hold on to and what to let go of."

Findings help identify mechanism of age-related memory deficits, highlight the importance of sleep for memory

Aging impairs the consolidation of memories during sleep, a process important in converting new memories into long-term ones, according to new animal research in the July 30 issue of The Journal of Neuroscience. The findings shed light on normal memory mechanisms and how they are disrupted by aging.

During sleep, the hippocampus, a brain region important in learning and memory, repeatedly "replays" brain activity from recent awake experiences. This replay process is believed to be important for memory consolidation. In the new study, Carol Barnes, PhD, and colleagues at the University of Arizona found reduced replay activity during sleep in old compared to young rats, and rats with the least replay activity performed the worst in tests of spatial memory.

Barnes and colleagues recorded hippocampal activity in 11 young and 11 old rats as they navigated several mazes for food rewards. Later, when the animals were asleep, the researchers recorded their hippocampal activity again. In the young animals, the sequence of neural activity recorded while the animals navigated the mazes was repeated when they slept. However, in most of the old animals, the sequence of neural activity recorded during sleep did not reflect the sequence of brain activity recorded in the maze. "These findings suggest that some of the memory impairment experienced during aging could involve a reduction in the automatic process of experience replay," said Michael Hasselmo, DPhil, at Boston University, an expert unaffiliated with the study.

Animals with more faithful sleep replay also performed better on memory tests. The researchers tested the same 22 rats on a spatial learning and memory task. Consistent with previous research, the young rats recalled the solution to the spatial task faster and more accurately than the old rats. In the old group, the researchers found that the top performers in the spatial memory task were also the ones that showed the best sleep replay. Irrespective of the animal's age, the researchers found that animals who more faithfully replayed the sequence of neural activity recorded in the maze while asleep also performed better on the spatial memory task. "This is the first study to suggest that an animal's ability to perform a spatial memory task may be related to the brain's ability to perform memory consolidation during sleep," said study author Barnes.

Identification of the specific memory deficit present in the aging brain may be a first step to preventing age-related memory loss. "This study's findings could inspire the development and testing of pharmacological agents designed to enhance memory replay phenomena," Hasselmo said.

If you are struggling to retrieve a word that you are certain is on the tip of your tongue, or trying to perfect a slapshot that will send your puck flying into a hockey net, or if you keep stumbling over the same sequence of notes on the piano, be warned: you might be unconsciously creating a pattern of failure, a new study reveals.

The research appeared on April 1 in The Quarterly Journal of Experimental Psychology.

Karin Humphreys, assistant professor in McMaster University’s Faculty of Science, and Amy Beth Warriner, an undergraduate student in the Department of Psychology, Neuroscience & Behaviour, suggest that most errors are repeated because the very act of making a mistake, despite receiving correction, constitutes the learning of that mistake.

Humphreys says the research came about as a result of her own experiences of repeatedly getting into a tip-of-the-tongue (or TOT) state on particular words. “This can be incredibly frustrating – you know you know the word, but you just can’t quite get it,” she said. “And once you have it, it is such a relief that you can’t imagine ever forgetting it again. But then you do. So we began thinking about the mechanisms that might underlie this phenomenon. We realized that it might not be a case of everyone having certain words that are difficult for them to remember, but that by getting into a tip-of-the-tongue state on a particular word once, they actually learn to go into that incorrect state when they try to retrieve the same word again.”

Humphreys and Warriner tested 30 students to see if their subjects could retrieve words after being given a definition. e.g. “What do you call an instrument for performing calculations by sliding beads along rods or grooves” (Answer: abacus). They then had to say whether they knew the answer, didn’t know it, or were in a TOT. If they were in a TOT, they were randomly assigned to spend either 10 or 30 seconds trying to retrieve the answer before finally being shown it. Two days later, subjects were tested on those same words again. One would assume that having been shown the correct word on Day 1 the subject would still remember it on Day 2. Not so. The subjects tended to TOT on the same words as before, and were especially more likely to do so if they had spent a longer time trying to retrieve them The longer time in the error state appears to reinforce that incorrect pattern of brain activation that caused the error.

“It’s akin to spinning one’s tires in the snow: despite your perseverance you’re only digging yourself a deeper rut,” the researchers explained. There might be a strategy to solve the recurrence of tip-of-the-tongue situations, which is what Warriner is currently working on for her honors thesis. "If you can find out what the word is as soon as possible—by looking it up, or asking someone—you should actually say it to yourself,” says Humphreys. “It doesn't need to be out loud, but you should at least say it to yourself. By laying down another procedural memory you can help ameliorate the effects of the error. However, what the research shows is that if you just can't figure it out, stop trying: you’re just digging yourself in deeper."

Very young brains process memories of fear differently than more mature ones, new research indicates. The findings appear in the Feb. 6 issue of The Journal of Neuroscience. The work significantly advances scientific understanding of when and how fear is stored and unlearned, and introduces new thinking on the implications of fear experience early in life.

“This important paper raises questions that are the ‘tip of the iceberg’ related to the very complex series of events that occur as we learn to fear something. In the real world, we become fearful, extinguish that fear, reacquire it at another time, and then conquer it yet again,” says John Krystal, MD, of Yale University and director of the clinical neuroscience division of the VA National Center for Post-Traumatic Stress Disorder. “Typically, we think about long-term, negative impact of fear learning, such as lifelong problems with anxiety. But this work highlights an avenue for adapting to early stresses that apparently can occur only early in life: to erase a learned fear from memory.” Krystal was not affiliated with the research.

Study co-authors Jee Hyun Kim and Rick Richardson, PhD, of the University of New South Wales in Sydney, homed in on the amygdala, using anesthesia to temporarily inactivate it and therefore isolate its role. The amygdala is critical for emotional learning and plays a central role in dulling the memory of a fear. Kim and Richardson trained rats that were 16 and 23 days old—the human equivalent of children and budding adolescents—to associate a specific sound with a mild shock to the foot. After subsequent training, when the sound was not followed by a shock, the animals’ fearful reaction to hearing the sound faded. Technically, this is known as “extinction,” and depended on the function of the amygdala.

In a second round of training, the researchers reintroduced the fear and tried to re-extinguish it. This time around, they found, only the older rats were able to do so without the amygdala. The researchers concluded that the age at which the initial extinction training occurred was critical to whether or not the rats’ fear faded the second time independently of the amygdala. The authors suggest that in the very young, it is primarily the amygdala that extinguishes fearful memories, but that mechanisms independent of the amygdala develop later.

This raises the possibility that fears unlearned at an early enough age are, in fact, erased. As brains develop, however, and related structures near the amygdala mature, these structures take on a greater role. Thus, fear in adolescence and later in life may not be erased, but instead be, for example, inhibited by a process of overlaying neutral memories on top of the initial fear reaction. The initial memory could still exist and be called on again. “Extinction in the young brain might forever erase early traumatic learning—but accepting this hypothesis will have to wait for more research,” says Mark Bouton, PhD, of the University of Vermont, who did not participate in the esearch. “What might change as the brain develops is where and how fear learning and extinction are stored and how they can be retrieved.”

Scientists are finding new evidence that a good night's rest plays a crucial role in cementing memories formed during the day.

One new study has identified a brain region involved, along with the hippocampus, in creating memories of the day's activities during sleep. Another study suggests melatonin, a hormone involved in regulating our day-night cycle, or "circadian rhythm," acts to suppress the formation of new memories as bedtime nears, perhaps in an effort to give memories made earlier in the day a chance to be prepared for long-term storage.

Both studies are detailed in the Nov. 16 issue of the journal Science.

Duke University Medical Center neuroscientists say the places a memory is processed in the brain may determine how someone can be absolutely certain of a past event that never occurred. These findings could help physicians better appreciate the memory changes that accompany normal aging or even lead to tools for the early diagnosis of Alzheimer's disease, according to Duke neuroscientist Roberto Cabeza, Ph.D.

Information retrieved from memory is simultaneously processed in two specific regions of the brain, each of which focuses on a different aspect of an past event. The medial temporal lobe (MTL), located at the base of the brain, focuses on specific facts about the event. The frontal parietal network (FPN), located at the top of the brain, is more likely to process the global gist of the event. The specific brain area accessed when one tries to remember something can ultimately determine whether or not we think the memory is true or false, the researchers found.

"Human memory is not like computer memory -- it isn't completely right all the time," said Cabeza, senior author of a paper appearing in the Journal of Neuroscience. "There are many occasions when people feel strongly about past events, even though they might not have occurred." Cabeza wanted to understand why someone could have such strong feelings of confidence about false memories. In his experiments, he scanned the brains of healthy volunteers with functional MRI as they took well-established tests of memory and false memory. Functional MRI is an imaging technique that shows what areas of the brain are used during specific mental tasks.

During the brain scans, Cabeza found that volunteers who were highly confident in memories that were indeed true showed increased activity in the fact-oriented MTL region. "This would make sense, because the MTL, with its wealth of specific details, would make the memory seem more vivid," Cabeza said. "For example, thinking about your breakfast this morning, you remember what you had, the taste of the food, the people you were with. The added richness of these details makes one more confident about the memory's truth."

On the other hand, volunteers who showed high confidence in memories that turned out to be false exhibited increased activity in the impressionistic FPN. The people drawing from this area of the brain recalled the gist or general idea of the event, and while they felt confident about their memories, they were often mistaken, since they could not recall the details of the memory.

These findings, coupled with the findings of other studies, can help explain what happens to the human brain as it ages, Cabeza said. "Specific memories don't last forever, but what ends up lasting are not specific details, but more general or global impressions," Cabeza said. "Past studies have shown that as normal brains age, they tend to lose the ability to recollect specifics faster than they lose the ability recall impressions. However, patients with Alzheimer's disease tend to lose both types of memories equally, which may prove to be a tool for early diagnosis."

Cabeza's colleague for this research was Hongkeun Kim at Daegu University in South Korea. The research was supported by the National Institutes of Health and Daegu University.

Brown, A.M (2007). A cognitive approach to dogmatism: An investigation into the relationship of verbal working memory and dogmatism. Journal of Research in Personality, 41 (4), 946-952.

Abstract: This study investigated the relationship of working memory to open and closed belief systems. Two hundred college students completed a working memory span test to measure verbal working memory, and Rokeach’s Dogmatism Scale (1956). Regression analysis was undertaken to determine the contribution of verbal working memory to dogmatism. A negative correlation was found between dogmatism scores and working memory scores (p = .002) confirming the hypothesis that those participants who display a larger working memory capacity would show lower levels of dogmatic beliefs than participants displaying a smaller working memory capacity. Error analysis was employed to determine the significance of inhibition processes; indicating that capacity limits in verbal working memory, and not processing deficits, were primarily responsible for poor working memory scores. Dogmatism was not found to be related to gender, age, ethnicity, religious affiliation, academic major, or level of education.

In the 1980's, a spate of high profile child abuse convictions gave way to heightened concern about false memory reports given by children. Take, for example, the case of Kelly Michaels, a preschool teacher who was convicted on 115 counts of sexual abuse based on the testimony of 20 of her pupils. After serving seven years of her 47 year sentence, Michaels' conviction was overturned after the techniques used to interview the children were shown to be coercive and highly suggestive.

Since then, a sizeable literature on children's false memories has accumulated and until recently, the picture that had emerged was quite consistent: false memories of events were found to decrease with age throughout childhood and adolescence. In other words, as we grow into adulthood, our memory accuracy improves.

However, psychologists Charles Brainerd and Valerie Reyna of Cornell University believe that the relationship between age and memory accuracy may not be so simple. Drawing upon fuzzy-trace theory — the popular psychological theory that humans encode information on a continuum from verbatim to "fuzzy" traces that convey a general meaning — Brainerd and Reyna predicted that false memories may actually increase with age under certain circumstances. In other words, adults would have less accurate memories than children. [read more]

Sleep not only protects memories from outside interferences, but also helps strengthen them, according to research that will be presented at the American Academy of Neurology’s 59th Annual Meeting in Boston, April 28 – May 5, 2007.

The study looked at memory recall with and without interference (competing information). Forty-eight people between the ages of 18 and 30 took part in the study. All had normal, healthy sleep routines and were not taking any medications. Participants were divided evenly into four groups—a wake group without interference, a wake group with interference, a sleep group without interference and a sleep group with interference. All groups were taught the same 20 pairs of words in the initial training session.

The wake groups were taught the word pairings at 9 a.m. and then tested on them at 9 p.m. after 12 hours awake. The sleep groups were taught the word pairs at 9 p.m. and tested on them at 9 a.m. after a night of sleep. Just prior to testing, the interference groups were given a second list of word pairs to remember. The first word in each pair was the same on both lists, but the second word was different, testing the brain’s ability to handle competing information, known as interference. The interference groups were then tested on both lists.

The study found that people who slept after learning the information performed best, successfully recalling more words. Those in the sleep group without interference were able to recall 12 percent more word pairings from the first list than the wake group without interference. With interference, the recall rate was 44 percent higher for the sleep group.

"This is the first study to show that sleep protects memories from interference," said study author Jeffrey Ellenbogen, MD, with Harvard Medical School in Boston, MA, and Fellow of the American Academy of Neurology. "These results provide important insights into how the sleeping brain interacts with memories: it appears to strengthen them. Perhaps, then, sleep disorders might worsen memory problems seen in dementia."

Memorizing a series of facts is one thing, understanding the big picture is quite another. Now a new study demonstrates that relational memory – the ability to make logical “big picture” inferences from disparate pieces of information – is dependent on taking a break from studies and learning, and even more important, getting a good night’s sleep.

Led by researchers at Beth Israel Deaconess Medical Center (BIDMC) and Brigham and Women’s Hospital (BWH), the findings appear on-line in today’s Early Edition of the Proceedings of the National Academy of Sciences (PNAS).

“Relational memory is a bit like solving a jigsaw puzzle,” explains senior author Matthew Walker, PhD, Director of the Sleep and Neuroimaging Laboratory at BIDMC and Assistant Professor of Psychology at Harvard Medical School (HMS). “It’s not enough to have all the puzzle pieces – you also have to understand how they fit together.”

Adds lead author Jeffrey Ellenbogen, MD, a postdoctoral fellow at HMS and sleep neurologist at BWH, “People often assume that we know all of what we know because we learned it directly. In fact, that’s only partly true. We actually learn individual bits of information and then apply them in novel, flexible ways.” For instance, if a person learns that A is greater than B and B is greater than C, then he or she knows those two facts. But embedded within those is a third fact – A is greater than C – which can be deduced by a process called transitive inference, the type of relational memory that the researchers examined in this study.

Earlier research by Walker and colleagues had shown that sleep actively improves task-oriented “procedural memory” – for example, learning to talk, to coordinate limbs, musicianship, or to play sports. Because relational memory is fundamental to knowledge and learning, Walker and Ellenbogen decided to explore how and when this “inferential” knowledge emerges, hypothesizing that it develops during “off-line” periods and that, like procedural memory, would be enhanced following a period of sleep.

So, the researchers tested 56 healthy college students, each of whom was shown five pairs of unfamiliar abstract patterns – colorful oval shapes resembling Faberge eggs. The students were then told that some of the patterns were “correct” while others were “incorrect,” for example, Shape A wins over Shape B, Shape B wins over Shape C, and so on. All of the students learned the individual pairs but were not told that there was a hidden “hierarchy” linking all five of the pairs together.

After a 30-minute study period, the students were separated into three groups to test their understanding of the larger “big picture” relationship between the individual patterns: Group One was tested after a period of 20 minutes; Group Two was tested after a 12-hour period; and Group Three was tested after a 24-hour time span. In addition, approximately half of the students in Group Two slept during the 12-hour period, while the other half remained awake. All of the students in Group Three had a full night’s sleep.

The test results showed striking differences among the three groups, especially between the students who had a period of sleep and those who remained awake. “Group One, the students who were tested soon after their initial learning period, performed the worst,” says Walker. “While they were able to learn and recall the component pieces [for example, Shape A is greater than Shape B, Shape B is greater than Shape C] they could not discern the hierarchical relationships between the pieces [Shape A is greater than Shape C] – they couldn’t yet see ‘the big picture.’” Groups Two and Three, on the other hand, demonstrated a clear understanding of the interrelationship between the pairs of shapes.

“These individuals were able to make leaps of inferential judgment just by letting the brain have time to unconsciously mull things over,” he says. But, perhaps most notable, he adds, when the inferences were particularly difficult, the students who had had periods of sleep in between learning and testing significantly outperformed the other groups. “This strongly implies that sleep is actively engaged in the cognitive processing of our memories,” notes Ellenbogen. “Knowledge appears to expand both over time and with sleep.”

Concludes Walker, “These findings point to an important benefit [of sleep] that we had not previously considered. Sleep not only strengthens a person’s individual memories, it appears to actually knit them together and helps realize how they are associated with one another. And this may, in fact, turn out to be the primary goal of sleep: You go to bed with pieces of the memory puzzle, and awaken with the jigsaw completed.”


20 April 2007
Beth Israel Deaconess Medical Center News

A Brown University-led research team has, for the first time, recorded activity inside the cells of the hippocampus while simultaneously measuring activity in the neocortex. Recordings from these two brain regions – seats of memory creation and storage – revealed a surprisingly complex pattern of activity. These findings, in the Proceedings of the National Academy of Sciences, are part of a growing body of evidence that challenges traditional theories of the role of sleep in learning and memory. [read more]

A common drug [propranolol] administered in the first hours following trauma to patients deemed to be at risk of developing post-traumatic stress disorder (PTSD) reduced the occurrence of PTSD, according to a study led by researchers at the University of Lille, France [in 2003].

While the study involved a small number of subjects, its results are encouraging, says its senior author, Charles Marmar, MD, associate chief of staff for mental health at the San Francisco VA Medical Center and professor and vice chair of psychiatry at University of California, San Francisco.

"The study is based on the new theory that PTSD is most likely to occur in patients who experience a particularly severe and prolonged response to trauma. If this model proves accurate after five or ten replications of studies like this one, it could have very profound ramifications. From a public health perspective, if you could identify the subgroup of people who are susceptible to PTSD, giving them this course of medication -- which is brief, very well tolerated and inexpensive -- could be very effective prevention [following major trauma] and may have great social relevance." The study appears in the November 1 issue of Biological Psychiatry. [read rest of article]

Also: The Memory Pill (60 Minutes video -- 26 Nov 2006)
Bad Memory? Wipe It Clean With New Pill (16 Jan 2006)