Chapter 13. Memory, Learning, and Development
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A long-term study has pointed to a link between breastfeeding and intelligence. The research in Brazil traced nearly 3,500 babies, from all walks of life, and found those who had been breastfed for longer went on to score higher on IQ tests as adults. Experts say the results, while not conclusive, appear to back current advice that babies should be exclusively breastfed for six months. But they say mothers should still have a choice about whether or not to do it. Regarding the findings - published in The Lancet Global Health - they stress there are many different factors other than breastfeeding that could have an impact on intelligence, although the researchers did try to rule out the main confounders, such as mother's education, family income and birth weight. Dr Bernardo Lessa Horta, from the Federal University of Pelotas in Brazil, said his study offers a unique insight because in the population he studied, breastfeeding was evenly distributed across social class - not something just practised by the rich and educated. Most of the babies, irrespective of social class, were breastfed - some for less than a month and others for more than a year. Those who were breastfed for longer scored higher on measures of intelligence as adults. They were also more likely to earn a higher wage and to have completed more schooling. Dr Horta believes breast milk may offer an advantage because it is a good source of long-chain saturated fatty acids which are essential for brain development. But experts say the study findings cannot confirm this and that much more research is needed to explore any possible link between breastfeeding and intelligence. © 2015 BBC.
By PAM BELLUCK What happens to forgotten memories — old computer passwords, friends’ previous phone numbers? Scientists have long held two different theories. One is that memories do not diminish but simply get overshadowed by new memories. The other is that older memories become weaker, that pulling to mind new passwords or phone numbers degrades old recollections so they do not interfere. The difference could be significant. If old memories stay strong and are merely papered over by new ones, they may be easier to recover. That could be positive for someone trying to remember an acquaintance’s name, but difficult for someone trying to lessen memories of abuse. It could suggest different strategies for easing traumatic memories, evaluating witness testimony about crimes, or helping students study for tests. Now, a study claims to provide evidence of memory’s weakening by showing that people’s ability to remember something and the pattern of brain activity that thing generates both appear to diminish when a competing memory gets stronger. Demonstrating sophisticated use of brain scans in memory research, authors of the study, published Monday in the journal Nature Neuroscience, appear to have identified neural fingerprints of specific memories, distinguishing brain activity patterns produced when viewing a picture of a necklace, say, from a picture of binoculars or other objects. The experiment, conducted by scientists in Birmingham and Cambridge, England, involved several stages with 24 participants first trained to associate words to two unrelated black and white pictures from lists of famous people, ordinary objects or scenes. © 2015 The New York Times Company
Keyword: Learning & Memory
Link ID: 20695 - Posted: 03.17.2015
By BENEDICT CAREY Behind all those canned compliments for older adults — spry! wily! wise! — is an appreciation for something that scientists have had a hard time characterizing: mental faculties that improve with age. Knowledge is a large part of the equation, of course. People who are middle-aged and older tend to know more than young adults, by virtue of having been around longer, and score higher on vocabulary tests, crossword puzzles and other measures of so-called crystallized intelligence. Still, young adults who consult their elders (mostly when desperate) don’t do so just to gather facts, solve crosswords or borrow a credit card. Nor, generally, are they looking for help with short-term memory or puzzle solving. Those abilities, called fluid intelligence, peak in the 20s. No, the older brain offers something more, according to a new paper in the journal Psychological Science. Elements of social judgment and short-term memory, important pieces of the cognitive puzzle, may peak later in life than previously thought. The postdoctoral fellows Joshua Hartshorne of M.I.T. and Laura Germine of Harvard and Massachusetts General Hospital analyzed a huge trove of scores on cognitive tests taken by people of all ages. The researchers found that the broad split in age-related cognition — fluid in the young, crystallized in the old — masked several important nuances. “This dichotomy between early peaks and later peaks is way too coarse,” Dr. Hartshorne said. “There are a lot more patterns going on, and we need to take those into account to fully understand the effects of age on cognition.” The new paper is hardly the first challenge to the scientific literature on age-related decline, and it won’t be the last. A year ago, German scientists argued that cognitive “deficits” in aging were caused largely by the accumulation of knowledge — that is, the brain slows down because it has to search a larger mental library of facts. That idea has stirred some debate among scientists. Experts said the new analysis raised a different question: Are there distinct, independent elements of memory and cognition that peak at varying times of life? © 2015 The New York Times Company
By John Horgan In 1990 The New York Times published a front-page article by Lawrence Altman, a reporter with a medical degree, announcing that scientists had discovered “a link between alcoholism and a specific gene.” The evidence for the "feel-good gene," which supposedly reduces anxiety, is flimsy, just like the evidence linking specific genes to high intelligence, violent aggression, homosexuality, bipolar disorder and countless other complex human traits and ailments. That was merely one in a string of reports in which the Times and other major media hyped what turned out to be erroneous claims linking complex traits and disorders—from homosexuality and high intelligence to schizophrenia and bipolar disorder—to specific genes. I thought those days were over, and that scientists and the media have learned to doubt extremely reductionist genetic accounts of complex traits and behaviors. I was wrong. Last Sunday, the “Opinion” section of the Times published an essay, “The Feel-Good Gene,” which states: “For the first time, scientists have demonstrated that a genetic variation in the brain makes some people inherently less anxious, and more able to forget fearful and unpleasant experiences. This lucky genetic mutation produces higher levels of anandamide–the so-called bliss molecule and our natural marijuana–in our brains. In short, some people are prone to be less anxious simply because they won the genetic sweepstakes and randomly got a genetic mutation that has nothing at all to do with strength of character.” This article, like the one touting the alcoholism gene 25 years ago, was written by a physician, Richard Friedman, professor of psychiatry at Weill Cornell Medical College. I emphasize this fact because scientific hype is often blamed on supposedly ignorant journalists like me rather than on physicians and other so-called experts. © 2015 Scientific American
By Maggie Fox Teenagers who use marijuana heavily grow up to have poor memories and also have brain abnormalities, a new study shows. The study cannot say which came first — the brain structure differences or the pot use. But it suggests there could be long-term effects of heavy marijuana use. A team at Northwestern University looked at 97 volunteers with and without mental illness. The dope smokers said they'd used marijuana daily starting at age 16 or 17, and said they had not used other drugs. The daily marijuana users had an abnormally shaped hippocampus and performed about 18 percent more poorly on long-term memory tasks, the researchers reported in the journal Hippocampus. The hippocampus is a part of the brain used in storing long-term memory. "The memory processes that appear to be affected by cannabis are ones that we use every day to solve common problems and to sustain our relationships with friends and family," said Dr. John Csernansky, who worked on the study. Previous research by the same Northwestern team showed heavy pot smokers had poor short-term and working memory and abnormally shaped brain structures including the striatum, globus pallidus and thalamus. "It is possible that the abnormal brain structures reveal a pre-existing vulnerability to marijuana abuse," Matthew Smith, who led the study, said in a statement.
By Emily Underwood From imaging babies to blasting apart kidney stones, ultrasound has proved to be a versatile tool for physicians. Now, several research teams aim to unleash the technology on some of the most feared brain diseases. The blood-brain barrier, a tightly packed layer of cells that lines the brain's blood vessels, protects it from infections, toxins, and other threats but makes the organ frustratingly hard to treat. A strategy that combines ultrasound with microscopic blood-borne bubbles can briefly open the barrier, in theory giving drugs or the immune system access to the brain. In the clinic and the lab, that promise is being evaluated. This month, in one of the first clinical tests, Todd Mainprize, a neurosurgeon at the University of Toronto in Canada, hopes to use ultrasound to deliver a dose of chemotherapy to a malignant brain tumor. And in some of the most dramatic evidence of the technique's potential, a research team reports this week in Science Translational Medicine that they used it to rid mice of abnormal brain clumps similar to those in Alzheimer's disease, restoring lost memory and cognitive functions. If such findings can be translated from mice to humans, “it will revolutionize the way we treat brain disease,” says biophysicist Kullervo Hynynen of the Sunnybrook Research Institute in Toronto, who originated the ultrasound method. Some scientists stress that rodent findings can be hard to translate to humans and caution that there are safety concerns about zapping the brain with even the low-intensity ultrasound used in the new study, which is similar to that used in diagnostic scans. © 2015 American Association for the Advancement of Science.
Link ID: 20685 - Posted: 03.12.2015
|By Daisy Yuhas The brain is a hotbed of electrical activity. Scientists have long known that brain cells communicate via electrical missives, created by charged atoms and molecules called ions as they travel across the membranes of those cells. But a new study suggests that in the days and weeks that lead up to a brain forming in an embryo or fetus, altering the electrical properties of these cells can dramatically change how the ensuing brain develops. Researchers at Tufts University and the University of Minnesota have investigated how the difference in charge on either side of a resting cell’s membrane—its electrical potential—helps build the brain. In previous work Tufts University developmental biologist Michael Levin found that patterns of electrical potentials in the earliest stages of an embryo’s development can direct how an animal’s body grows, and that manipulating those potentials can cause a creature to sprout extra limbs, tails or functioning eyes. Now, Levin’s group has investigated how these potentials shape the brain. Working with frog embryos the researchers first used dyes to see the patterns of electrical potentials that precede brain development. They noticed that before the development of a normal brain the cells lining the neural tube, a structure that eventually becomes the brain and spinal cord, have extreme differences in ionic charge within and outside the membrane that houses the cells. In other words, these cells are extremely polarized. © 2015 Scientific American
Keyword: Development of the Brain
Link ID: 20684 - Posted: 03.12.2015
Older people could improve or maintain their mental function through heart healthy lifestyle changes, a large randomized trial for dementia prevention shows. Researchers in Finland and Sweden designed a trial to tackle risk factors for Alzheimer's disease. The 1,260 Finns aged 60 to 77 participating in the study were all considered at risk of dementia based on standard test scores. Half were randomly assigned to receive advice from health professionals on maintaining a healthy diet, aerobic and muscle training exercises, brain training exercises and regular checks of blood pressure, height and weight for body mass index and physical exams for two years or regular health advice. Participants in the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability or FINGER study had their cognitive function measured in a battery of mental tests. "The main hypothesis was that simultaneous changes in several risk factors (even of smaller magnitude) would lead to a protective effect on cognition," Miia Kivipelto from the Karolinska Institute in Stockholm and her co-authors said in Wednesday's issue of The Lancet. Overall, test scores were 25 per cent in the diet and training group than the control group. There was no effect on memory. ©2015 CBC/Radio-Canada.
Link ID: 20683 - Posted: 03.12.2015
Mutations in the presenilin-1 gene are the most common cause of inherited, early-onset forms of Alzheimer’s disease. In a new study, published in Neuron, scientists replaced the normal mouse presenilin-1 gene with Alzheimer’s-causing forms of the human gene to discover how these genetic changes may lead to the disorder. Their surprising results may transform the way scientists design drugs that target these mutations to treat inherited or familial Alzheimer’s, a rare form of the disease that affects approximately 1 percent of people with the disorder. The study was partially funded by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health. For decades, it has been unclear exactly how the presenilin mutations cause Alzheimer’s disease. Presenilin is a component of an important enzyme, gamma secretase, which cuts up amyloid precursor protein into two protein fragments, Abeta40 and Abeta42. Abeta42 is found in plaques, the abnormal accumulations of protein in the brain which are a hallmark of Alzheimer’s. Numerous studies suggested that presenilin-1 mutations increased activity of gamma-secretase. Investigators have developed drugs that block gamma-secretase, but they have so far failed in clinical trials to halt the disease. The study led by Raymond Kelleher, M.D., Ph.D. and Jie Shen, Ph.D., professors of neurology at Harvard Medical School, Boston, provides a plot twist in the association of presenilin-1 mutations and inherited Alzheimer’s disease. Using mice with altered forms of the presenilin gene, Drs. Kelleher and Shen discovered that the mutations may cause the disease by decreasing, rather than increasing, the activity of gamma-secretase.
|By Esther Landhuis As we age, we seem to get worse at ignoring irrelevant stimuli. It's what makes restaurant conversations challenging—having to converse while also shutting out surrounding chatter. New research bears out the aging brain's distractibility but also suggests that training may help us tune out interference. Scientists at Brown University recruited seniors and twentysomethings for a visual experiment. Presented with a sequence of letters and numbers, participants were asked to report back only the numbers—all the while disregarding a series of meaningless dots. Sometimes the dots moved randomly, but other times they traveled in a clear direction, making them harder to ignore. Older participants ended up accidentally learning the dots' patterns, based on the accuracy of their answers when asked which way the dots were moving, whereas young adults seemed able to suppress that information and focus on the numbers, the researchers reported last November in Current Biology. In a separate study published in Neuron, scientists at the University of California, San Francisco, showed they could train aging brains to become less distractible. Their regimen helped aging rats as well as older people. The researchers played three different sounds and rewarded trainees for identifying a target tone while ignoring distracter frequencies. As the subjects improved, the task grew more challenging—the distracting tone became harder to discriminate from the target. © 2015 Scientific American,
By Douglas Starr In 1906, Hugo Münsterberg, the chair of the psychology laboratory at Harvard University and the president of the American Psychological Association, wrote in the Times Magazine about a case of false confession. A woman had been found dead in Chicago, garroted with a copper wire and left in a barnyard, and the simpleminded farmer’s son who had discovered her body stood accused. The young man had an alibi, but after questioning by police he admitted to the murder. He did not simply confess, Münsterberg wrote; “he was quite willing to repeat his confession again and again. Each time it became richer in detail.” The young man’s account, he continued, was “absurd and contradictory,” a clear instance of “the involuntary elaboration of a suggestion” from his interrogators. Münsterberg cited the Salem witch trials, in which similarly vulnerable people were coerced into self-incrimination. He shared his opinion in a letter to a Chicago nerve specialist, which made the local press. A week later, the farmer’s son was hanged. Münsterberg was ahead of his time. It would be decades before the legal and psychological communities began to understand how powerfully suggestion can shape memory and, in turn, the course of justice. In the early nineteen-nineties, American society was recuperating from another panic over occult influence; Satanists had replaced witches. One case, the McMartin Preschool trial, hinged on nine young victims’ memories of molestation and ritual abuse—memories that they had supposedly forgotten and then, after being interviewed, recovered. The case fell apart, in 1990, because the prosecution could produce no persuasive evidence of the victims’ claims. A cognitive psychologist named Elizabeth Loftus, who had consulted on the case, wondered whether the children’s memories might have been fabricated—in Münsterberg’s formulation, involuntarily elaborated—rather than actually recovered.
Keyword: Learning & Memory
Link ID: 20679 - Posted: 03.12.2015
Mo Costandi Neuroscientists in France have implanted false memories into the brains of sleeping mice. Using electrodes to directly stimulate and record the activity of nerve cells, they created artificial associative memories that persisted while the animals snoozed and then influenced their behaviour when they awoke. Manipulating memories by tinkering with brain cells is becoming routine in neuroscience labs. Last year, one team of researchers used a technique called optogenetics to label the cells encoding fearful memories in the mouse brain and to switch the memories on and off, and another used it to identify the cells encoding positive and negative emotional memories, so that they could convert positive memories into negative ones, and vice versa. The new work, published today in the journal Nature Neuroscience, shows for the first time that artificial memories can be implanted into the brains of sleeping animals. It also provides more details about how populations of nerve cells encode spatial memories, and about the important role that sleep plays in making such memories stronger. Karim Benchenane of the French National Centre for Scientific Research (CNRS) in Paris and his colleagues implanted electrodes into the brains of 40 mice, targeting the medial forebrain bundle (MFB), a component of the reward circuitry, and the CA1 region of the hippocampus, which contains at least three different cell types that encode the memories needed for spatial navigation. © 2015 Guardian News and Media Limited
By Rachel Rabkin Peachman Many women with a history of depression who take antidepressants assume that once they get pregnant, they should try to wean themselves off their meds to avoid negative side effects for the baby. A new large study published in the journal Pediatrics challenges one reason behind that assumption. The research found that taking selective serotonin reuptake inhibitors (the antidepressants also known as S.S.R.I.s) while pregnant does not increase the risk of asthma in the resulting babies. What is associated with an increased risk of asthma? According to this study and other research, untreated prenatal depression. “The mechanisms underlying the association of prenatal depression and asthma are unknown,” said Dr. Xiaoqin Liu, the lead author of the Pediatrics study and an epidemiologist at Aarhus University in Denmark. An association between prenatal depression and asthma does not mean that prenatal depression causes asthma. There could be other reasons for the correlation, genetic or environmental, or both. For example, people who live in dense, polluted urban areas could be at an increased risk of both asthma and depression. The researchers used Denmark’s national registries to evaluate all singleton babies born from 1996 to 2007, and identify the mothers who had a diagnosis of depression or had used antidepressants, or both, during pregnancy or one year beforehand. Using a statistical model, the study authors found that prenatal depression — with or without the use of antidepressants — was associated with a 25 percent increased risk of asthma in children as compared with children whose mothers did not have a record of depression. © 2015 The New York Times Company
by Penny Sarchet For some of us, it might have been behind the bikeshed. Not so the African cotton leafworm moth (Spodoptera littoralis), which can choose any one of a vast number of plant species to mate on. But these moths remember their first time, returning to the same species in search of other mates. In the wild, this moth feeds and mates on species from as many as 40 different plant families. That much choice means there's usually something available to eat, but selecting and remembering the best plants is tricky. So, recalling what you ate as a larva, or where you first copulated, may help narrow down which plants provide better quality food or are more likely to attract other potential mates. Magali Proffit and David Carrasco of the Swedish University of Agricultural Sciences in Alnarp and their colleagues have discovered that this moth's first mating experience shapes its future preferences. These moths have an innate preference for cotton plants over cabbage. But when the researchers made them mate for the first time on cabbage, the moths later showed an increased preference for mating or laying eggs on this plant. Further experiments revealed that moths didn't just favour plants they were familiar with, even in combination with a sex pheromone – mating had to be involved. © Copyright Reed Business Information Ltd.
By Will Boggs MD NEW YORK (Reuters Health) - Adolescents with a history of childhood trauma show different neural responses to subjective anxiety and craving, researchers report. "I think the finding of increased activation of insula, anterior cingulate, and prefrontal cortex in response to stress cues in the high- relative to low-trauma group, while arguably not necessarily unexpected, is important as it suggests that youth exposed to higher levels of trauma may experience different brain responses to similar stressors," Dr. Marc N. Potenza from Yale University, New Haven, Connecticut told Reuters Health by email. Childhood trauma has been associated with anxiety and depression, as well as obesity, risky sexual behavior, and substance use. Previous imaging studies have not investigated neural responses to personalized stimuli, Dr. Potenza and his colleagues write in Neuropsychopharmacology, online January 8. The team used functional MRI to assess regional brain activations to personalized appetitive (favorite food), aversive (stress), and neutral/relaxing cues in 64 adolescents, including 33 in the low-trauma group and 31 in the high-trauma group. Two-thirds of the adolescents had been exposed to cocaine prenatally, with prenatal cocaine exposure being significantly over-represented in the high-trauma group. Compared with the low-trauma group, the high-trauma group showed increased responsivity in several cortical regions in response to stress, as well as decreased activation in the cerebellar vermis and right cerebellum in response to neutral/relaxing cues. But the two groups did not differ significantly in their responses to favorite-food cues, the researchers found. © 2015 Scientific American
Children who attend school in heavy traffic areas may show slower cognitive development and lower memory test scores, Spanish researchers have found. About 21,000 premature deaths are attributed to air pollution in Canada each year, according to the Canadian Medical Association. The detrimental effects of air pollution on cardiovascular health and on the lungs are well documented and now researchers are looking at its effects on the brain. To that end, Dr. Jordi Sunyer and his colleagues from the Centre for Research in Environmental Epidemiology in Barcelona measured three aspects of memory and attentiveness in more than 2,700 primary school children every three months over 12 months. "What was surprising for us is among our children, we see very robust, consistent effects," Sunyer said Tuesday from Rome. The associations between slower cognitive development and higher levels of air pollutants remained after the researchers took factors such as parents’ education, commuting time, smoking in the home and green spaces at school into account. The researchers measured air pollutants from traffic twice, in the school courtyard and inside the classroom for schools with high and low traffic-related air pollution. Pollutants from burning fossil fuels, carbon, nitrogen dioxide and ultrafine particles were measured. For example, working memory improved 7.4 per cent among children in highly polluted schools compared with 11.5 per cent among those in less polluted schools. ©2015 CBC/Radio-Canada.
Lights, sound, action: we are constantly learning how to incorporate outside sensations into our reactions in specific situations. In a new study, brain scientists have mapped changes in communication between nerve cells as rats learned to make specific decisions in response to particular sounds. The team then used this map to accurately predict the rats’ reactions. These results add to our understanding of how the brain processes sensations and forms memories to inform behavior. “We’re reading the memories in the brain,” said Anthony Zador, M.D., Ph.D., professor at Cold Spring Harbor Laboratory, New York, and senior author of the study, published in Nature. The work was funded by the National Institutes of Health and led by Qiaojie Xiong, Ph.D., a former postdoctoral researcher in Dr. Zador’s laboratory. “For decades scientists have been trying to map memories in the brain,” said James Gnadt, Ph.D., a program director at the National Institute of Neurological Disorders and Stroke (NINDS), one of the NIH institutes that funded the study. “This study shows that scientists can begin to pinpoint the precise synapses where certain memories form and learning occurs.” The communication points, or synapses, that Dr. Zador’s lab studied were in the striatum, an integrating center located deep inside the brain that is known to play an important role in coordinating the translation of thoughts and sensations into actions. Problems with striatal function are associated with certain neurological disorders such as Huntington’s disease in which affected individuals have severely impaired skill learning.
By Nicholas Bakalar Gout, a form of arthritis, is extremely painful and associated with an increased risk for cardiovascular problems. But there is a bright side: It may be linked to a reduced risk for Alzheimer’s disease. Researchers compared 59,204 British men and women with gout to 238,805 without the ailment, with an average age of 65. Patients were matched for sex, B.M.I., smoking, alcohol consumption and other characteristics. The study, in The Annals of the Rheumatic Diseases, followed the patients for five years. They found 309 cases of Alzheimer’s among those with gout and 1,942 among those without. Those with gout, whether they were being treated for the condition or not, had a 24 percent lower risk of Alzheimer’s disease. The reason for the connection is unclear. But gout is caused by excessive levels of uric acid in the blood, and previous studies have suggested that uric acid protects against oxidative stress. This may play a role in limiting neuron degeneration. “This is a dilemma, because uric acid is thought to be bad, associated with heart disease and stroke,” said the senior author, Dr. Hyon K. Choi, a professor of medicine at Harvard. “This is the first piece of data suggesting that uric acid isn’t all bad. Maybe there is some benefit. It has to be confirmed in randomized trials, but that’s the interesting twist in this story.” © 2015 The New York Times Company
By Roni Caryn Rabin When my mother, Pauline, was 70, she lost her sense of balance. She started walking with an odd shuffling gait, taking short steps and barely lifting her feet off the ground. She often took my hand, holding it and squeezing my fingers. Her decline was precipitous. She fell repeatedly. She stopped driving, and she could no longer ride her bike in a straight line along the C&O Canal. The woman who taught me the sidestroke couldn’t even stand in the shallow end of the pool. “I feel like I’m drowning,” she’d say. A retired psychiatrist, my mother had numerous advantages — education, resources and insurance — but, still, getting the right diagnosis took nearly 10 years. Each expert saw the problem through the narrow prism of a single specialty. Surgeons recommended surgery. Neurologists screened for common incurable conditions. The answer was under their noses, in my mother’s hunches and her family history. But it took a long time before someone connected the dots. My mother was using a walker by the time she was told she had a rare condition that causes gait problems and cognitive loss, and is one of the few treatable forms of dementia. The bad news was that it had taken so long to get the diagnosis that some of the damage might not be reversible. “This should be one of the first things physicians look for in an older person,” my mother said recently. “You can actually do something about it.”
Link ID: 20643 - Posted: 03.03.2015
By ROBERT PEAR WASHINGTON — Federal investigators say they have found evidence of widespread overuse of psychiatric drugs by older Americans with Alzheimer’s disease, and are recommending that Medicare officials take immediate action to reduce unnecessary prescriptions. The findings will be released Monday by the Government Accountability Office, an arm of Congress, and come as the Obama administration has already been working with nursing homes to reduce the inappropriate use of antipsychotic medications like Abilify, Risperdal, Zyprexa and clozapine. But in the study, investigators said officials also needed to focus on overuse of such drugs by people with dementia who live at home or in assisted living facilities. The Department of Health and Human Services “has taken little action” to reduce the use of antipsychotic drugs by older adults living outside nursing homes, the report said. Doctors sometimes prescribe antipsychotic drugs to calm patients with dementia who display disruptive behavior like hitting, yelling or screaming, the report said. Researchers said this was often the case in nursing homes that had inadequate numbers of employees. Dementia is most commonly associated with a decline in memory, but doctors say it can also cause changes in mood or personality and, at times, agitation or aggression. Experts have raised concern about the use of antipsychotic drugs to address behavioral symptoms of Alzheimer’s and other forms of dementia. The Food and Drug Administration says antipsychotic drugs are often associated with an increased risk of death when used to treat older adults with dementia who also have psychosis. © 2015 The New York Times Company