Posts tagged psychology
Articles and news from the latest research reports.
Alzheimer’s disease: 15-minute test could spot early sign of dementia
A simple 15-minute test which can be taken at home can spot the early signs of Alzheimer’s disease, researchers claim.
The exam which can be completed online or by hand, tests language ability, reasoning, problem solving skills and memory.
Results can then be shared with doctors to help spot early symptoms of cognitive issues such as early dementia or Alzheimer’s disease.
The research was published in The Journal of Neuropsychiatry and Clinical Neurosciences.
Caffeine has positive effect on memory
Whether it’s a mug full of fresh-brewed coffee, a cup of hot tea, or a can of soda, consuming caffeine is the energy boost of choice for millions who want to wake up or stay up.
Now, researchers at Johns Hopkins University have found another use for the popular stimulant: memory enhancer.
Michael Yassa, an assistant professor of psychological and brain sciences at Johns Hopkins, and his team of scientists found that caffeine has a positive effect on our long-term memory. Their research, published by the journal Nature Neuroscience, shows that caffeine enhances certain memories at least up to 24 hours after it is consumed.
"We’ve always known that caffeine has cognitive-enhancing effects, but its particular effects on strengthening memories and making them resistant to forgetting has never been examined in detail in humans," said Yassa, senior author of the paper. "We report for the first time a specific effect of caffeine on reducing forgetting over 24 hours."
The Johns Hopkins researchers conducted a double-blind trial in which participants who did not regularly eat or drink caffeinated products received either a placebo or a 200-milligram caffeine tablet five minutes after studying a series of images. Salivary samples were taken from the participants before they took the tablets to measure their caffeine levels. Samples were taken again one, three, and 24 hours afterwards.
The next day, both groups were tested on their ability to recognize images from the previous day’s study session. On the test, some of the visuals were the same as those from the day before, some were new additions, and some were similar but not the same.
More members of the caffeine group were able to correctly identify the new images as “similar” to previously viewed images rather than erroneously citing them as the same.
The brain’s ability to recognize the difference between two similar but not identical items, called pattern separation, reflects a deeper level of memory retention, the researchers said.
"If we used a standard recognition memory task without these tricky similar items, we would have found no effect of caffeine," Yassa said. "However, using these items requires the brain to make a more difficult discrimination—what we call pattern separation, which seems to be the process that is enhanced by caffeine in our case."
The memory center in the human brain is the hippocampus, a seahorse-shaped area in the medial temporal lobe of the brain. The hippocampus is the switchbox for all short- and long-term memories. Most research done on memory—the effects of concussions in athletes, of war-related head injuries, and of dementia in the aging population—focuses on this area of the brain.
Until now, caffeine’s effects on long-term memory had not been examined in detail. Of the few studies done, the general consensus was that caffeine has little or no effect on long-term memory retention.
The research is different from prior experiments because the subjects took the caffeine tablets only after they had viewed and attempted to memorize the images.
"Almost all prior studies administered caffeine before the study session, so if there is an enhancement, it’s not clear if it’s due to caffeine’s effects on attention, vigilance, focus, or other factors," Yassa said. "By administering caffeine after the experiment, we rule out all of these effects and make sure that if there is an enhancement, it’s due to memory and nothing else."
According to the U.S. Food and Drug Administration, 90 percent of people worldwide consume caffeine in one form or another. In the United States, 80 percent of adults consume caffeine every day. The average adult has an intake of about 200 milligrams—the same amount used in the Yassa study—or roughly one cup of strong coffee per day.
Yassa’s team completed the research at Johns Hopkins before his lab moved to the University of California, Irvine, at the start of this year.
"The next step for us is to figure out the brain mechanisms underlying this enhancement," Yassa said. "We can use brain-imaging techniques to address these questions. We also know that caffeine is associated with healthy longevity and may have some protective effects from cognitive decline like Alzheimer’s disease. These are certainly important questions for the future."
Unpacking the toolkit of human consciousness
No matter how different they seem — the learned and contemplative neuroscientist versus the toy orangutan with a penchant for off-color jokes — almost any adult who experiences them knows that Princeton University professor Michael Graziano is the voice behind his simian puppet Kevin. Yet to most listeners, Kevin — who acts as the comic relief when Graziano publicly presents his work — nonetheless has a distinct personality and consciousness — he seems aware of and comments on his surroundings in his own unique way.
While Kevin is not “real” in the sense of being an animate biological being, Graziano, a professor of psychology and the Princeton Neuroscience Institute, suggests that humans attribute consciousness to the puppet in the same way that we attribute consciousness to each other and to ourselves. Graziano has developed a new theory of consciousness he calls the “attention schema theory” that suggests that specialized systems in the human brain compute information about the things of which a person is aware, and project the property of consciousness onto ourselves and others. In that sense, the puppet’s consciousness is every bit as real as that of anyone wincingly laughing at his jokes about living atop Graziano’s hand.
Sleep is the Price the Brain Pays for Learning
Why do animals ranging from fruit flies to humans all need to sleep? After all, sleep disconnects them from their environment, puts them at risk and keeps them from seeking food or mates for large parts of the day.
Two leading sleep scientists from the University of Wisconsin School of Medicine and Public Health say that their synaptic homeostasis hypothesis of sleep or “SHY” challenges the theory that sleep strengthens brain connections.
The SHY hypothesis, which takes into account years of evidence from human and animal studies, says that sleep is important because it weakens the connections among brain cells to save energy, avoid cellular stress, and maintain the ability of neurons to respond selectively to stimuli.
“Sleep is the price the brain must pay for learning and memory,” says Dr. Giulio Tononi, of the UW Center for Sleep and Consciousness. “During wake, learning strengthens the synaptic connections throughout the brain, increasing the need for energy and saturating the brain with new information. Sleep allows the brain to reset, helping integrate newly learned material with consolidated memories, so the brain can begin anew the next day.”
Tononi and his co-author Dr. Chiara Cirelli, both professors of psychiatry, explain their hypothesis in a review article in today’s issue of the journal Neuron. Their laboratory studies sleep and consciousness in animals ranging from fruit flies to humans; SHY takes into account evidence from molecular, electrophysiological and behavioral studies, as well as from computer simulations.”Synaptic homeostasis” refers to the brain’s ability to maintain a balance in the strength of connections within its nerve cells.
Why would the brain need to reset? Suppose someone spent the waking hours learning a new skill, such as riding a bike. The circuits involved in learning would be greatly strengthened, but the next day the brain will need to pay attention to learning a new task. Thus, those bike- riding circuits would need to be damped down so they don’t interfere with the new day’s learning.
“Sleep helps the brain renormalize synaptic strength based on a comprehensive sampling of its overall knowledge of the environment,” Tononi says, “rather than being biased by the particular inputs of a particular waking day.”
The reason we don’t also forget how to ride a bike after a night’s sleep is because those active circuits are damped down less than those that weren’t actively involved in learning. Indeed, there is evidence that sleep enhances important features of memory, including acquisition, consolidation, gist extraction, integration and “smart forgetting,” which allows the brain to rid itself of the inevitable accumulation of unimportant details.
However, one common belief is that sleep helps memory by further strengthening the neural circuits during learning while awake. But Tononi and Cirelli believe that consolidation and integration of memories, as well as the restoration of the ability to learn, all come from the ability of sleep to decrease synaptic strength and enhance signal-to-noise ratios.
While the review finds testable evidence for the SHY hypothesis, it also points to open issues. One question is whether the brain could achieve synaptic homeostasis during wake, by having only some circuits engaged, and the rest off-line and thus resetting themselves.
Other areas for future research include the specific function of REM sleep (when most dreaming occurs) and the possibly crucial role of sleep during development, a time of intense learning and massive remodeling of brain.
Researchers find rare genetic cause of Tourette syndrome
A rare genetic mutation that disrupts production of histamine in the brain is a cause of the tics and other abnormalities of Tourette syndrome, according to new findings by Yale School of Medicine researchers.
The findings, reported Jan. 8 in the journal Neuron, suggest that existing drugs that target histamine receptors in the brain might be useful in treating the disorder. Tourette syndrome afflicts up to 1% of children, and a smaller percentage of adults.
“These findings give us a new window into what’s going on in the brain in people with Tourette. That’s likely to lead us to new treatments,” said Christopher Pittenger, associate professor in the psychiatry and psychology departments and in the Yale Child Study Center, and senior author of the paper.
Histamine is commonly associated with allergy, but it also plays an important role as a signaling molecule in the brain. Interactions with this brain system explain why some allergy medications cause people to feel sleepy.
In 2010, Yale researchers showed that a family with nine members suffering from Tourette’s carried a mutation in a gene called HDC that disrupts the production of histamine. The new work demonstrates that this mutation causes the disorder. Mice with the same mutation develop symptoms similar to those found in Tourette’s, the Yale team showed. Also, these mice and the patients that carry the HDC mutation showed abnormalities in signaling by the neurotransmitter dopamine in parts of the brain associated with Tourette’s and related conditions.
Drug companies have developed medications that target brain-specific histamine receptors in an effort to treat schizophrenia and ADHD. While not approved for general use yet, those drugs or others that target histamine receptors should be tested to see whether they can treat symptoms of Tourette syndrome, Pittenger said.
Babbling babies – responding to one-on-one ‘baby talk’ – master more words
Common advice to new parents is that the more words babies hear the faster their vocabulary grows. Now new findings show that what spurs early language development isn’t so much the quantity of words as the style of speech and social context in which speech occurs.
Researchers at the University of Washington and University of Connecticut examined thousands of 30-second snippets of verbal exchanges between parents and babies. They measured parents’ use of a regular speaking voice versus an exaggerated, animated baby talk style, and whether speech occurred one-on-one between parent and child or in group settings.
“What our analysis shows is that the prevalence of baby talk in one-on-one conversations with children is linked to better language development, both concurrent and future,” said Patricia Kuhl, co-author and co-director of UW’s Institute for Learning & Brain Sciences.
The more parents exaggerated vowels – for example “How are youuuuu?” – and raised the pitch of their voices, the more the 1-year olds babbled, which is a forerunner of word production. Baby talk was most effective when a parent spoke with a child individually, without other adults or children around.
(Listen to a mother use baby talk with her child)
“The fact that the infant’s babbling itself plays a role in future language development shows how important the interchange between parent and child is,” Kuhl said.
The findings will be published in an upcoming issue of the journal Developmental Science.
Twenty-six babies about 1 year of age wore vests containing audio recorders that collected sounds from the children’s auditory environment for eight hours a day for four days. The researchers used LENA (“language environment analysis”) software to examine 4,075 30-second intervals of recorded speech. Within those segments, the researchers identified who was talking in each segment, how many people were there, whether baby talk – also known as “parentese” – or regular voice was used, and other variables.
When the babies were 2 years old, parents filled out a questionnaire measuring how many words their children knew. Infants who had heard more baby talk knew more words. In the study, 2-year olds in families who spoke the most baby talk in a one-on-one social context knew 433 words, on average, compared with the 169 words recognized by 2-year olds in families who used the least babytalk in one-on-one situations.
The relationship between baby talk and language development persisted across socioeconomic status and despite there only being 26 families in the study.
“Some parents produce baby talk naturally and they don’t realize they’re benefiting their children,” said first author Nairán Ramírez-Esparza, an assistant psychology professor at the University of Connecticut. “Some families are more quiet, not talking all the time. But it helps to make an effort to talk more.”
Previous studies have focused on the amount of language babies hear, without considering the social context. The new study shows that quality, not quantity, is what matters.
“What this study is adding is that how you talk to children matters. Parentese is much better at developing language than regular speech, and even better if it occurs in a one-on-one interaction,” Ramirez-Esparza said.
Parents can use baby talk when going about everyday activities, saying things like, “Where are your shoooes?,” “Let’s change your diiiiaper,” and “Oh, this tastes goooood!,” emphasizing important words and speaking slowly using a happy tone of voice.
“It’s not just talk, talk, talk at the child,” said Kuhl. “It’s more important to work toward interaction and engagement around language. You want to engage the infant and get the baby to babble back. The more you get that serve and volley going, the more language advances.”
This is how your brain tells time
Did you make it to work on time this morning? Go ahead and thank the traffic gods, but also take a moment to thank your brain. The brain’s impressively accurate internal clock allows us to detect the passage of time, a skill essential for many critical daily functions. Without the ability to track elapsed time, our morning shower could continue indefinitely. Without that nagging feeling to remind us we’ve been driving too long, we might easily miss our exit.
But how does the brain generate this finely tuned mental clock? Neuroscientists believe that we have distinct neural systems for processing different types of time, for example, to maintain a circadian rhythm, to control the timing of fine body movements, and for conscious awareness of time passage. Until recently, most neuroscientists believed that this latter type of temporal processing – the kind that alerts you when you’ve lingered over breakfast for too long – is supported by a single brain system. However, emerging research indicates that the model of a single neural clock might be too simplistic. A new study, recently published in the Journal of Neuroscience by neuroscientists at the University of California, Irvine, reveals that the brain may in fact have a second method for sensing elapsed time. What’s more, the authors propose that this second internal clock not only works in parallel with our primary neural clock, but may even compete with it.
Researchers report technique that enables patient with ‘word blindness’ to read again
In the journal Neurology, researchers report a novel technique that enables a patient with “word blindness” to read again.
Word blindness is a rare neurological condition. (The medical term is “alexia without agraphia.”) Although a patient can write and understand the spoken word, the patient is unable to read.
The article is written by Jason Cuomo, Murray Flaster, MD, PhD and Jose Biller, MD, of Loyola University Medical Center.
Here’s how the technique works: When shown a word, the patient looks at the first letter. Although she clearly sees it, she cannot recognize it. So beginning with the letter A, she traces each letter of the alphabet over the unknown letter until she gets a match. For example, when shown the word Mother, she will trace the letters of the alphabet, one at a time, until she comes to M and finds a match. Three letters later, she guesses correctly that the word is Mother.
"To see this curious adaption in practice is to witness the very unique and focal nature" of the deficit, the authors write.
The authors describe how word blindness came on suddenly to a 40-year-old kindergarten teacher and reading specialist. She couldn’t make sense of her lesson plan, and her attendance sheet was as incomprehensible as hieroglyphs. She also couldn’t tell time.
The condition was due to a stroke that probably was caused by an unusual type of blood vessel inflammation within the brain called primary central nervous system angiitis.
Once a passionate reader, she was determined to learn how to read again. But none of the techniques that she had taught her students – phonics, sight words, flash cards, writing exercises, etc. – worked. So she taught herself a remarkable new technique that employed tactile skills that she still possessed.
The woman can have an emotional reaction to a word, even if she can’t read it. Shown the word “dessert,” she says “Oooh, I like that.” But when shown “asparagus,” she says, “Something’s upsetting me about this word.”
Shown two personal letters that came in the mail, she correctly determined which was sent by a friend of her mother’s and which was sent by one of her own friends. “When asked who these friends were, she could not say, but their names nevertheless provoked an emotional response that served as a powerful contextual clue,” the authors write.
What she most misses is reading books to children. She teared up as she told the authors: “One day my mom was with the kids in the family, and they were all curled up next to each other, and they were reading. And I started to cry, because that was something I couldn’t do.”
(Source: eurekalert.org)
Disease and sleep: Recent studies find new links
One in five U.S. adults shows signs of chronic sleep deprivation, and a shortage of sleep has been linked to health problems as different as diabetes and Alzheimer’s disease. Recent studies have found some interesting connections between illness and what is happening in our brains as we snooze.
Alcohol, tobacco, drug use far higher in severely mentally ill
In the largest ever assessment of substance use among people with severe psychiatric illness, researchers at Washington University School of Medicine in St. Louis and the University of Southern California have found that rates of smoking, drinking and drug use are significantly higher among those who have psychotic disorders than among those in the general population.
The study is published online in the journal JAMA Psychiatry.
The finding is of particular concern because individuals with severe mental illness are more likely to die younger than people without severe psychiatric disorders.
“These patients tend to pass away much younger, with estimates ranging from 12 to 25 years earlier than individuals in the general population,” said first author Sarah M. Hartz, MD, PhD, assistant professor of psychiatry at Washington University. “They don’t die from drug overdoses or commit suicide — the kinds of things you might suspect in severe psychiatric illness. They die from heart disease and cancer, problems caused by chronic alcohol and tobacco use.”
The study analyzed smoking, drinking and drug use in nearly 20,000 people. That included 9,142 psychiatric patients diagnosed with schizophrenia, bipolar disorder or schizoaffective disorder — an illness characterized by psychotic symptoms such as hallucinations and delusions, and mood disorders such as depression.
The investigators also assessed nicotine use, heavy drinking, heavy marijuana use and recreational drug use in more than 10,000 healthy people without mental illness.
The researchers found that 30 percent of those with severe psychiatric illness engaged in binge drinking, defined as drinking four servings of alcohol at one time. In comparison, the rate of binge drinking in the general population is 8 percent.
Among those with mental illness, more than 75 percent were regular smokers. This compares with 33 percent of those in the control group who smoked regularly. There were similar findings with heavy marijuana use: 50 percent of people with psychotic disorders used marijuana regularly, versus 18 percent in the general population. Half of those with mental illness also used other illicit drugs, while the rate of recreational drug use in the general population is 12 percent.
“I take care of a lot of patients with severe mental illness, many of whom are sick enough that they are on disability,” said Hartz. “And it’s always surprising when I encounter a patient who doesn’t smoke or hasn’t used drugs or had alcohol problems.”
Hartz said another striking finding from the study is that once a person develops a psychotic illness, protective factors such as race and gender don’t have their typical influence.
Previous research indicates that Hispanics and Asians tend to have lower rates of substance abuse than European Americans. The same is true for women, who tend to smoke, drink and use illicit drugs less often than men.
“We see protective effects in these subpopulations,” Hartz explained. “But once a person has a severe mental illness, that seems to trump everything.”
That’s particularly true, she said, with smoking. During the last few decades, smoking rates have declined in the general population. People over age 50 are much more likely than younger people to have been regular smokers at some point in their lives. For example, about 40 percent of those over 50 used to smoke regularly. Among those under 30, fewer than 20 percent have been regular smokers. But among the mentally ill, the smoking rate is more than 75 percent, regardless of the patient’s age.
“With public health efforts, we’ve effectively cut smoking rates in half in healthy people, but in the severely mentally ill, we haven’t made a dent at all,” she said.
Until recently, smoking was permitted in most psychiatric hospitals and mental wards. Hartz believes that many psychiatrists decided that their sickest patients had enough problems without having to worry about quitting smoking, too. There also were concerns about potential dangers from using nicotine-replacement therapy, while continuing to smoke since smoking is so prevalent among the mentally ill. Recent studies, however, have found those concerns were overblown.
The question, she said, is whether being more aggressive in trying to curb nicotine, alcohol and substance use in patients with severe psychiatric illness can lengthen their lives. Hartz believes health professionals who treat the mentally ill need to do a better job of trying to get them to stop smoking, drinking and using drugs.
“Some studies have shown that although we psychiatrists know that smoking, drinking and substance use are major problems among the mentally ill, we often don’t ask our patients about those things,” she said. “We can do better, but we also need to develop new strategies because many interventions to reduce smoking, drinking and drug use that have worked in other patient populations don’t seem to be very effective in these psychiatric patients.”
(Source: news.wustl.edu)