Flannel Shirt

It's a wonder I can remember where I put my keys

Memory isn't what it's been cracked up to be.

Your memory is a wily time traveler, plucking fragments of the present and inserting them into the past, reports a new Northwestern Medicine® study. In terms of accuracy, it's no video camera.

 

Rather, the memory rewrites the past with current information, updating your recollections with new experiences.

Love at first sight, for example, is more likely a trick of your memory than a Hollywood-worthy moment.

"When you think back to when you met your current partner, you may recall this feeling of love and euphoria," said lead author Donna Jo Bridge, a postdoctoral fellow in medical social sciences at Northwestern University Feinberg School of Medicine. "But you may be projecting your current feelings back to the original encounter with this person."

The study will be published Feb. 5 in the Journal of Neuroscience.

This the first study to show specifically how memory is faulty, and how it can insert things from the present into memories of the past when those memories are retrieved. The study shows the exact point in time when that incorrectly recalled information gets implanted into an existing memory.

To help us survive, Bridge said, our memories adapt to an ever-changing environment and help us deal with what's important now.

"Our memory is not like a video camera," Bridge said. "Your memory reframes and edits events to create a story to fit your current world. It's built to be current."

All that editing happens in the hippocampus, the new study found. The hippocampus, in this function, is the memory's equivalent of a film editor and special effects team.

For the experiment, 17 men and women studied 168 object locations on a computer screen with varied backgrounds such as an underwater ocean scene or an aerial view of Midwest farmland. Next, researchers asked participants to try to place the object in the original location but on a new background screen. Participants would always place the objects in an incorrect location.

For the final part of the study, participants were shown the object in three locations on the original screen and asked to choose the correct location. Their choices were: the location they originally saw the object, the location they placed it in part 2 or a brand new location.

"People always chose the location they picked in part 2," Bridge said. "This shows their original memory of the location has changed to reflect the location they recalled on the new background screen. Their memory has updated the information by inserting the new information into the old memory."

Participants took the test in an MRI scanner so scientists could observe their brain activity. Scientists also tracked participants' eye movements, which sometimes were more revealing about the content of their memories -- and if there was conflict in their choices -- than the actual location they ended up choosing.

The notion of a perfect memory is a myth, said Joel Voss, senior author of the paper and an assistant professor of medical social sciences and of neurology at Feinberg.

"Everyone likes to think of memory as this thing that lets us vividly remember our childhoods or what we did last week," Voss said. "But memory is designed to help us make good decisions in the moment and, therefore, memory has to stay up-to-date. The information that is relevant right now can overwrite what was there to begin with."

Bridge noted the study's implications for eyewitness court testimony. "Our memory is built to change, not regurgitate facts, so we are not very reliable witnesses," she said.

A caveat of the research is that it was done in a controlled experimental setting and shows how memories changed within the experiment. "Although this occurred in a laboratory setting, it's reasonable to think the memory behaves like this in the real world," Bridge said.

 

Sight and sound separated in autistics

Wednesday we were at the State Capitol to watch our neighbor Barb sworn in as our state representative. During the ceremony we got to sit right on the floor of the chamber, which was cool. The acoustics outside the chamber in the halls, where they held a little reception, was incredibly loud and garbled. There was a grammar school class who got to go see the ceremony plus lots of other folks. I was only a couple of feet from Joan and our neighbors Nancy and Pam and I couldn't understand a word that was said. 

I sat back in my chair, ate my cake and drank my coffee and looked at the crowd and let all the noise pour over me. I wondered if this is what it's like when you have a stroke, everything just jumbled noise.

Maybe it's what autistics experience.

Like watching a foreign movie that was badly dubbed, children with autism spectrum disorders (ASD) have trouble integrating simultaneous information from their eyes and their ears, according to a Vanderbilt study published today in The Journal of Neuroscience.

The study, led by Mark Wallace, Ph.D., director of the Vanderbilt Brain Institute, is the first to illustrate the link and strongly suggests that deficits in the sensory building blocks for language and communication can ultimately hamper social and communication skills in children with autism.

"There is a huge amount of effort and energy going into the treatment of children with autism, virtually none of it is based on a strong empirical foundation tied to sensory function," Wallace said. "If we can fix this deficit in early sensory function then maybe we can see benefits in language and communication and social interactions."

And the findings could have much broader applications because sensory functioning is also changed in developmental disabilities such as dyslexia and schizophrenia, Wallace said.

In the study, Vanderbilt researchers compared 32 typically developing children ages 6-18 years old with 32 high-functioning children with autism, matching the groups in virtually every possible way including IQ.

Study participants worked through a battery of different tasks, largely all computer generated. Researchers used different types of audiovisual stimuli such as simple flashes and beeps, more complex environmental stimuli like a hammer hitting a nail, and speech stimuli, and asked the participants to tell them whether the visual and auditory events happened at the same time.

The study found that children with autism have an enlargement in something known as the temporal binding window (TBW), meaning the brain has trouble associating visual and auditory events that happen within a certain period of time.

"Children with autism have difficulty processing simultaneous input from audio and visual channels. That is, they have trouble integrating simultaneous information from their eyes and their ears," said co-author Stephen Camarata, Ph.D., professor of Hearing and Speech Sciences. "It is like they are watching a foreign movie that was badly dubbed, the auditory and visual signals do not match in their brains."

A second part of the study found that children with autism also showed weaknesses in how strongly they "bound" or associated audiovisual speech stimuli.

"One of the classic pictures of children with autism is they have their hands over their ears," Wallace said. "We believe that one reason for this may be that they are trying to compensate for their changes in sensory function by simply looking at one sense at a time. This may be a strategy to minimize the confusion between the senses."

Wallace noted that the recently-released Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, (DSM-5), which serves as a universal authority for psychiatric diagnosis, now acknowledges sensory processing as a core deficit in autism.

An overnight rinse

Why do we need to sleep? When I first visited Portland, around 25 years ago, I was impressed that the city had trucks to drive around downtown in the early hours of the morning and hose down all the sidewalks. The place was fresh and clean for new day. It may be that sleep serves a similar function, to give the brain a rinse.

A good night's rest may literally clear the mind. Using mice, researchers showed for the first time that the space between brain cells may increase during sleep, allowing the brain to flush out toxins that build up during waking hours. These results suggest a new role for sleep in health and disease. The study was funded by the National Institute of Neurological Disorders and Stroke (NINDS), part of the NIH.

"Sleep changes the cellular structure of the brain. It appears to be a completely different state," said Maiken Nedergaard, M.D., D.M.Sc., co-director of the Center for Translational Neuromedicine at the University of Rochester Medical Center in New York, and a leader of the study.

For centuries, scientists and philosophers have wondered why people sleep and how it affects the brain. Only recently have scientists shown that sleep is important for storing memories. In this study, Dr. Nedergaard and her colleagues unexpectedly found that sleep may be also be the period when the brain cleanses itself of toxic molecules.

Their results, published in Science, show that during sleep a plumbing system called the glymphatic system may open, letting fluid flow rapidly through the brain. Dr. Nedergaard's lab recently discovered the glymphatic system helps control the flow of cerebrospinal fluid (CSF), a clear liquid surrounding the brain and spinal cord.

"It's as if Dr. Nedergaard and her colleagues have uncovered a network of hidden caves and these exciting results highlight the potential importance of the network in normal brain function," said Roderick Corriveau, Ph.D., a program director at NINDS.

Initially the researchers studied the system by injecting dye into the CSF of mice and watching it flow through their brains while simultaneously monitoring electrical brain activity. The dye flowed rapidly when the mice were unconscious, either asleep or anesthetized. In contrast, the dye barely flowed when the same mice were awake.

"We were surprised by how little flow there was into the brain when the mice were awake," said Dr. Nedergaard. "It suggested that the space between brain cells changed greatly between conscious and unconscious states."

To test this idea, the researchers used electrodes inserted into the brain to directly measure the space between brain cells. They found that the space inside the brains increased by 60 percent when the mice were asleep or anesthetized.

"These are some dramatic changes in extracellular space," said Charles Nicholson, Ph.D., a professor at New York University's Langone Medical Center and an expert in measuring the dynamics of brain fluid flow and how it influences nerve cell communication.

Certain brain cells, called glia, control flow through the glymphatic system by shrinking or swelling. Noradrenaline is an arousing hormone that is also known to control cell volume. Similar to using anesthesia, treating awake mice with drugs that block noradrenaline induced unconsciousness and increased brain fluid flow and the space between cells, further supporting the link between the glymphatic system and consciousness.

Previous studies suggest that toxic molecules involved in neurodegenerative disorders accumulate in the space between brain cells. In this study, the researchers tested whether the glymphatic system controls this by injecting mice with labeled beta-amyloid, a protein associated with Alzheimer's disease, and measuring how long it lasted in their brains when they were asleep or awake. Beta-amyloid disappeared faster in mice brains when the mice were asleep, suggesting sleep normally clears toxic molecules from the brain.

"These results may have broad implications for multiple neurological disorders," said Jim Koenig, Ph.D., a program director at NINDS. "This means the cells regulating the glymphatic system may be new targets for treating a range of disorders."

The results may also highlight the importance of sleep.

"We need sleep. It cleans up the brain," said Dr. Nedergaard.

Have a cup of coffee

If you drink a couple of cups of coffee every day you're less likely to kill yourself.

Keep drinking your morning cup of joe, coffee drinkers. Aside from a jolt of energy, caffeinated coffee may lower the suicide risk in men and women by 50 percent, Harvard researchers indicated in a recent study.

Reviewing data from three large-scale U.S. studies, the team from the Harvard School of Public Health compared the risk of suicide for adults who consumed two to four caffeinated cups per day with that of non-coffee drinkers, those who drank much less coffee per day and people who chose decaf.

The results, published earlier this month in the The World Journal of Biological Psychiatry, were striking. Comparatively, the suicide risk for those who drank two to four cups per day was about 50 percent less than the risk for subjects in the other groups. (The total sample included more than 200,000 participants, who were studied for time spans of at least 16 years.)

"Unlike previous investigations, we were able to assess association of consumption of caffeinated and non-caffeinated beverages, and we identify caffeine as the most likely candidate of any putative protective effect of coffee," lead researcher Michel Lucas, a research fellow in the university's department of nutrition, said in a statement.

The team's findings are, perhaps, not surprising since caffeinated coffee has been linked to a lower risk of depression among women in the past. In a 2011 study, also conducted by Harvard researchers, women who drank coffee were shown to have a 15 percent reduced risk of depression as compared to non-coffee drinkers.

Speaking to The Huffington Post, Lucas stressed that it's the caffeine in coffee that's primarily responsible for these effects. He linked the lowered risks of depression and suicide to the impact caffeine has on the brain or, more specifically, on neurotransmitters that have been shown to have an effect on emotions.

And while other drinks like soda and tea also offer caffeine, they don't contain nearly the same levels as coffee.

"Caffeine from coffee is about 80 percent caffeine intake," Lucas estimated. "In one cup of coffee, you could have about 140 mg of caffeine."

"In tea, for example, you have about 47 mg," he told HuffPost, adding that someone would need about three more cups of tea to achieve the same effect as one cup of coffee.

However, as the researchers indicated in the study, moderation is still key. (Though caffeine intoxication was already a disorder in the Diagnostic and Statistical Manual of Mental Disorders, the latest version, DSM-5, added caffeine withdrawal as a related diagnosis.)

"Overall, our results suggest that there is little further benefit for consumption above two to three cups/day or 400 mg of caffeine/day," the authors wrote.

The Harvard study joins a growing body of scientific evidence, which has provided confirmation of the health benefits of coffee.

Last year alone, published research linked moderate coffee intake with delayed Alzheimer's onset, lowered risk of heart failure and reduced risk of basil cell carcinoma -- the most common type of skin cancer.

The on-off empathy switch for psychopaths

It means that they can be trained, but it also explains other things about them.

Psychopaths do not lack empathy, rather they can switch it on at will, according to new research.

Placed in a brain scanner, psychopathic criminals watched videos of one person hurting another and were asked to empathise with the individual in pain.

Only when asked to imagine how the pain receiver felt did the area of the brain related to pain light up.

Scientists, reporting in Brain, say their research explains how psychopaths can be both callous and charming.

The team proposes that with the right training, it could be possible to help psychopaths activate their "empathy switch", which could bring them a step closer to rehabilitation.

The ability to empathise with others - to put yourself in someone else's shoes - is crucial to social development in order to respond appropriately in everyday situations.

Criminals with psychopathy characteristically show a reduced ability to empathise with others, including their victims. Evidence suggests they are also more likely to reoffend upon release than criminals without the psychiatric condition.

Psychopathy is a personality disorder characterised by superficial charm, pathological lying and a diminished capacity for remorse.

Now scientists have found that only when asked to empathise did the criminals' empathy reaction, also known as the mirror system, fire up the same way as it did for the controls. Without instruction, they show reduced activity in the regions of the brain associated with pain.

This mirror system refers to the mirror neurons in our brain which are known to activate when we watch someone do a task and when we do it ourselves. They are thought to play a vital role in the ability to empathise with others.

Christian Keysers from the University of Groningen, the Netherlands, and senior author of the study, said it could change the way psychopathic criminals were viewed.

"The predominant notion had been that they are callous individuals, unable to feel emotions themselves and therefore unable to feel emotions in others.

"Our work shows it's not that simple. They don't lack empathy but they have a switch to turn it on and off. By default, it seems to be off."

The fact that they have the capacity to switch empathy on, at least under certain conditions, could have a positive side to it, Prof Keysers said.

"The notion psychopaths have no empathy at all was a bleak prospect. It would make it very hard for them to have normal moral development.

"Now that we've shown they have empathy - even if only in certain conditions - we can give therapists something to work with," Prof Keysers told BBC News.

But he explained that it was not yet known how this wilful capacity for empathy could be transformed into the spontaneous empathy most of us have.

Essi Viding from University College London, who was not involved with the study, said it was an extremely interesting finding, but that it remained unclear whether the psychopathic criminals' experience of empathy felt the same as that of the controls.

"It's dangerous to look at brain activation and say that it means they're empathising. They are able to generate a typical neural response, but that doesn't mean they have the same empathetic experience," Prof Viding told BBC News.

"We know they can generate the same response but they do that in an active and effortful way. Under free-viewing conditions they don't seem to. Just because they can emphasise, doesn't mean they will.

"Psychopathic criminals are clearly different. The million-dollar question is whether we can devise therapeutic interventions that would shift them do this more automatically."

Randall Salekin, from the University of Alabama, US, who works with youth offenders said: "These findings fit with much of the treatment I am doing using a mental model program, whereby youth are informed about how the brain works and then asked to make specific plans for improving their lives.

"This study is impressive because it actually shows the brain mechanisms or neural networks involved in activating the inmates' empathy."

 

If you take Ambien...

...and y0u're stressed about something, maybe you shouldn't. It screws with your sleep spindles.

Sleep researchers from University of California campuses in Riverside and San Diego have identified the sleep mechanism that enables the brain to consolidate emotional memory and found that a popular prescription sleep aid heightens the recollection of and response to negative memories.

Their findings have implications for individuals suffering from insomnia related to posttraumatic stress disorder (PTSD) and other anxiety disorders who are prescribed zolpidem (Ambien) to help them sleep.

The study -- "Pharmacologically Increasing Sleep Spindles Enhances Recognition for Negative and High-arousal Memories" -- appears in theJournal of Cognitive Neuroscience.

Mednick and UC San Diego psychologists Erik J. Kaestner and John T. Wixted determined that a sleep feature known as sleep spindles -- bursts of brain activity that last for a second or less during a specific stage of sleep -- are important for emotional memory.

Research Mednick published earlier this year demonstrated the critical role that sleep spindles play in consolidating information from short-term to long-term memory in the hippocampus, located in the cerebral cortex of the brain. Zolpidem enhanced the process, a discovery that could lead to new sleep therapies to improve memory for aging adults and those with dementia, Alzheimer's and schizophrenia. It was the first study to show that sleep can be manipulated with pharmacology to improve memory.

"We know that sleep spindles are involved in declarative memory -- explicit information we recall about the world, such as places, people and events, " she explained.

But until now, researchers had not considered sleep spindles as playing a role in emotional memory , focusing instead on rapid eye movement (REM) sleep.

Using two commonly prescribed sleep aids -- zolpidem and sodium oxybate (Xyrem) -- Mednick, Kaestner and Wixted were able to tease apart the effects of sleep spindles and rapid eye movement (REM) sleep on the recall of emotional memories. They determined that sleep spindles, not REM, affect emotional memory.

The researchers gave zolpidem, sodium oxybate (Xyrem) and a placebo to 28 men and women between the ages of 18 and 39 who were normal sleepers, allowing several days between doses to allow the pharmaceuticals to leave their bodies. The participants viewed standardized images known to elicit positive and negative responses for one second before and after taking supervised naps. They recalled more images that had negative or highly arousing content after taking zolpidem, a finding that also suggests that the brain may favor consolidation of negative memories, she said.

"I was surprised by the specificity of the results, that the emotional memory improvement was specifically for the negative and high-arousal memories, and the ramifications of these results for people with anxiety disorders and PTSD," Mednick said. "These are people who already have heightened memory for negative and high-arousal memories. Sleep drugs might be improving their memories for things they don't want to remember."

The study may have even broader implications, the researchers said. Clinical guidelines of the U.S. Department of Veterans Affairs and Department of Defense recommend against the routine use of benzodiazepines to treat PTSD, although their use increased among men and women with PTSD between 2003 and 2010. The effects of benzodiazepines on sleep are similar to those of zolpidem.

The U.S. Air Force uses zolpidem as one of the prescribed "no-go pills" to help flight crews calm down after taking stimulants to stay awake during long missions, the researchers noted in the study.

"In light of the present results, it would be worthwhile to investigate whether the administration of benzodiazepine-like drugs may be increasing the retention of highly arousing and negative memories, which would have a countertherapeutic effect," they wrote. "Further research on the relationship between hypnotics and emotional mood disorders would seem to be in order."