Biological Psychology Links

LA CROSSE, Wis. - For as long as he can remember, Brad Williams has been able to recall the most trifling dates and details about his life. For example, he can tell you it was Aug. 18, 1965, when his family stopped at Red Barn Hamburger during a road trip through Michigan. He was 8 years old at the time. And he had a burger, of course. “It was a Wednesday,” recalled Williams, now 51. “We stayed at a motel that night in Clare, Michigan. It seemed more like a cabin.” To Williams and his family, his ability to recall events — and especially dates — is a regular source of amusement. But according to one expert, Williams’ skill might rank his memory among the best in the world. Doctors are now studying him, and a woman with similar talents, hoping to achieve a deeper understanding of memory. Williams, a radio anchor in La Crosse, seems to enjoy having his memory tested. Name a date from the last 40 years and, after a few moments, he can typically tell you what he did that day and what was in the news. Exercise your mind “Let’s see,” he mused, gazing into the distance for about five seconds. “That would be around when Magic Johnson announced he had HIV. Yes, a Thursday. There was a big snowstorm here the week before.” © 2008 The Associated Press.

By KATIE HAFNER SAN FRANCISCO — When David Bunnell, a magazine publisher who lives in Berkeley, Calif., went to a FedEx store to send a package a few years ago, he suddenly drew a blank as he was filling out the forms. “I couldn’t remember my address,” said Mr. Bunnell, 60, with a measure of horror in his voice. “I knew where I lived, and I knew how to get there, but I didn’t know what the address was.” Mr. Bunnell is among tens of millions of baby boomers who are encountering the signs, by turns amusing and disconcerting, that accompany the decline of the brain’s acuity: a good friend’s name suddenly vanishing from memory; a frantic search for eyeglasses only to find them atop the head; milk taken from the refrigerator then put away in a cupboard. “It’s probably one of the most frightening aspects of the changes we undergo as we age,” said Nancy Ceridwyn, director of educational initiatives at the American Society on Aging. “Our memories are who we are. And if we lose our memories we lose that groundedness of who we are.” At the same time, boomers are seizing on a mounting body of evidence that suggests that brains contain more plasticity than previously thought, and many people are taking matters into their own hands, doing brain fitness exercises with the same intensity with which they attack a treadmill. Copyright 2008 The New York Times Company

By CARL ZIMMER “Why are humans so smart?” is a question that fascinates scientists. Tadeusz Kawecki, an evolutionary biologist at the University of Fribourg, likes to turn around the question. “If it’s so great to be smart,” Dr. Kawecki asks, “why have most animals remained dumb?” Dr. Kawecki and like-minded scientists are trying to figure out why animals learn and why some have evolved to be better at learning than others. One reason for the difference, their research finds, is that being smart can be bad for an animal’s health. Learning is remarkably widespread in the animal kingdom. Even the microscopic vinegar worm, Caenorhadits elegans, can learn, despite having just 302 neurons. It feeds on bacteria. But if it eats a disease-causing strain, it can become sick. The worms are not born with an innate aversion to the dangerous bacteria. They need time to learn to tell the difference and avoid becoming sick. Many insects are also good at learning. “People thought insects were little robots doing everything by instinct,” said Reuven Dukas, a biologist at McMaster University. Copyright 2008 The New York Times Company

NEW YORK - Brain scans of older people in a noisy lab machine give biological backing to the idea that distraction hampers memory with aging, researchers reported Wednesday. The finding bolsters a theory about one reason why memory weakens with age: older people have more trouble remembering some things because they’re more easily distracted when they try to learn them. The memory exercise reported in the latest issue of the Journal of Neuroscience dealt with recognizing faces, but the findings apply to the more general task of trying to remember something a person sees or hears, said lead author Dale Stevens. Story continues below ↓advertisement | your ad here Stevens, a postdoctoral researcher at Harvard University, did the work while at the Rotman Research Institute at Baycrest, which is affiliated with the University of Toronto. Older people who have to learn something should do all they can to focus on that task and eliminate potential distractions, he advised. The study compared 10 healthy people in their 60s and 70s to a dozen younger volunteers, ages 22 to 36. Their brains were scanned while they looked at photographs of people they did not know. As each photograph was displayed for one second, the volunteers were asked if they’d seen it before in the study. © 2008 The Associated Press

By Tina Hesman Saey You snooze, you lose connections between brain cells, two new studies suggest. People have known for some time that getting enough sleep is crucial for proper brain function. “If you don’t get enough sleep your ability to acquire, process and recall information is going to be impaired,” says Paul Shaw, a neuroscientist at Washington University in St. Louis and coauthor of one of the new studies. But scientists debate exactly how sleep helps the brain learn and remember. Two studies appearing in the April 3 Science suggest that sleep weakens or severs connections between brain cells to make way for new information. A study by Giorgio Gilestro, Giulio Tononi and Chiara Cirelli of the University of Wisconsin–Madison shows that proteins found in the connections between neurons, called synapses, build up in fruit fly brains while the flies are awake. Depriving flies of sleep leads to ever-greater levels of synaptic proteins, the researchers show. Levels of the proteins decrease as the flies sleep. Scientists usually determine synapse strength by measuring electrical activity of neurons, but fruit fly brains are far too small for electrical measurements, Cirelli says. The proteins, she says, are markers of synaptic strength. If true, the new finding would offer support for the theory of synaptic homeostasis, advanced by Tononi and Cirelli. The theory holds that sleep scales back the strength of connections between neurons, weakening the strongest connections and completely eliminating the weakest synapses. The cutbacks help save resources, the researchers say, and boost the signal of important memories over the noise of unneeded connections (SN: 12/20/08, p. 9). © Society for Science & the Public 2000 - 2009

By SEAN B. CARROLL I have long suspected that fish are smarter than we give them credit for. As a child, I had an aquarium with several pet goldfish. They certainly knew it was feeding time when my hand appeared over their tank, and they excitedly awaited their delicious fish flakes. They also exhibited a darker, disturbing behavior. Evidently, a safe life with abundant food was not fulfilling. From time to time, either sheer ennui or the long gray Toledo winter got to one of the fish and it ended its torment with a leap to my bedroom floor. Maybe my anthropomorphizing is a bit over the top. But, really, just how smart are fish? Can they learn? A 10-gallon tank with a plastic sunken pirate ship is certainly not the most stimulating habitat. But in the colorful, diverse and dangerous world of coral reefs, fish must be able to recognize not only food, but also to discriminate friends from foes, and mates from rivals, and to take the best action. In such a complex and dynamic environment, it would pay to be flexible and able to learn. A series of studies has recently revealed that reef fish are surprisingly adaptable. Freshly caught wild fish quickly learn new tasks and can learn to discriminate among colors, patterns and shapes, including those they have never encountered. These studies suggest that learning and interpreting new stimuli play important roles in the lives of reef fish. Copyright 2009 The New York Times Company

By HENRY FOUNTAIN Songbirds are not born with songs in their heads, but learn them from others. And as in a game of telephone, it would seem natural that, over generations, the songs might change. That is what happens with many species, some more dramatically than others. The songs of indigo buntings change so much, for example, that songs that are five years apart are almost completely different. But with other species, the songs are more stable. Now, thanks to some old audio recordings, researchers have determined just how stable some songbirds’ songs can be. The songbird in question is not just any old bird, but a member of a famous group of finches that Charles Darwin studied in the Gal�pagos Islands. Using recordings of Geospiza fortis, the medium ground finch, made 38 years apart, Jeffrey Podos of the University of Massachusetts and Eben Goodale, who is now at the University of California, San Diego, found that some songs have persisted over four decades. The researchers conducted a statistical analysis of songs, using elements like number of notes, note duration and trill rate. As they report in Biology Letters, in each year’s recordings there is a lot of variability in the songs. But from one period to another, there are some songs that match quite closely. Copyright 2010 The New York Times Company

By Nikhil Swaminathan You may be hard-pressed to recall events after a night of binge drinking, but a new report suggests that low to moderate alcohol consumption may actually enhance memory. "There are human epidemiological data of others indicating that mild [to] moderate drinking may paradoxically improve cognition in people compared to abstention," says Maggie Kalev, a research fellow in molecular medicine and pathology at the University of Auckland in New Zealand and a co-author of an article in The Journal of Neuroscience describing results of a study she and other researchers performed on rats. "This is similar to a glass of wine protecting against heart disease, however the mechanism is different." Kalev and Matthew During, a professor of molecular virology, immunology and medical genetics at The Ohio State University College of Medicine and a principal investigator of gene therapy at Auckland, initially set out to study the role of N-methyl-D-aspartic acid (NMDA) receptors in the neuronal processes of normal and diseased animals. (NMDA receptors are critical to memory, because they regulate the strength of synapses (spaces) between nerve cells through which the cells communicate.) But during their research, they discovered that memory was enhanced when one of its subunits, known as NR1, was strengthened in the hippocampus (a central brain region implicated in episodic memory). They then reviewed previous experiments, which had turned up a link between alcohol consumption and NR1 activity. © 1996-2007 Scientific American, Inc.

by Greg Miller Where did I leave my car keys? Did I come into this room to get something? And what was that person's name again? Getting old often means getting a little forgetful. Now researchers working with mice think they have found a new reason why. They've identified molecular changes in the brains of aging mice that prevent learning and memory genes from being switched on as they are in younger animals. If the findings translate to humans, they may one day lead to drugs that stave off dementia or even the normal cognitive declines of old age. Indeed, a certain class of drugs already in development for treating cancer might fit the bill. Previous studies had found age-related changes in gene expression in the hippocampus, a crucial memory center in the brain. Other work implicated histones—tiny protein spools that control gene expression by winding or unwinding DNA—in learning and memory. Neuroscientist Andr� Fischer of the European Neuroscience Institute in Göttingen, Germany, and colleagues wanted to probe the histone connection further. They hypothesized that aging might change how histones function, causing alterations in gene expression that contribute to memory problems. To test the idea, Fischer and colleagues compared old and young mice. Old mice don't have car keys to lose track of, but they do struggle to remember a place where they once received a nasty shock or a hidden platform in a pool of murky water. The team found staggering differences in gene expression between juvenile 3-month-old mice and 16-month-old mice (equivalent to late middle age in humans). An hour after being trained to associate a particular chamber with an impending shock to the foot, nearly 2000 genes in the hippocampus became more active in the younger mice compared with just six genes in the older mice. © 2010 American Association for the Advancement of Science.

Heidi Ledford It’s a common situation: you’re embroiled in an argument over a fact and you know for certain that you have the right answer. But when someone rushes to their laptop to google the correct answer, you discover that you were wrong. Whether in a fight with a spouse or giving testimony on the witness stand, it is clear that our memories are not always trustworthy. Now, researchers have found that although those vivid false memories may seem indistinguishable from true memories to you, but they are sometimes processed by different parts of the brain1. The results could one day be used to devise an early test for Alzheimer’s disease, or to assess the accuracy of witness testimony, says study author Roberto Cabeza, a neuroscientist at Duke University in Durham, North Carolina. Cabeza and Hongkeun Kim of Daegu University in South Korea asked 11 people to read lists of words that fall into a certain category, such as ‘farm animals’. The subjects were later asked whether specific words had occurred on the original lists, while functional magnetic resonance imaging was used to measure the changes in blood flow to different areas of their brains. The participants were also asked to say how confident they were in their answers. © 2007 Nature Publishing Group

Ker Than Stitching together personal details gets harder as we get older.GETTYOld age does more than stealthily steal away our most cherished memories: it also seems to diminish our ability to imagine things. This finding, detailed in the January issue of the journal Psychological Science 1, supports the ‘prospective brain’ hypothesis, the idea that imagining the future and remembering the past rely on the same neural machinery. “One implication of this study is that imagining is quite closely related to, and dependent on, remembering, perhaps more so than we previously realized,” says Dan Schacter of Harvard University. In the study, Schacter and his team asked groups of young and old participants, with average ages of 25 and 72, respectively, to recount a personal episode from their past or imagine a personal experience in their future in response to cue words. Details in the participants’ narratives were categorized as either 'internal' or 'external'. Internal memories are similar to scenes from a movie: they contain specific subjects and take place in particular settings and time periods. External memories consist mostly of general facts about the world, such as 'the sky is blue'. © 2008 Nature Publishing Group

Heidi Ledford It’s a classic mistake: you arrive at the grocery store hungry, and everything seems irresistible. Researchers have now worked out how a hunger-induced hormone called ghrelin can make all that food seem so desirable. The hormone stimulates the same ‘reward centres’ of the brain that have been linked to drug-seeking behaviour, they say. But it also activates regions of the brain involved with making memories: people injected with ghrelin remember pictures of food more clearly a day later. The appetite-stimulating effects of ghrelin are already being tested to see if the hormone can encourage eating in cancer patients. And inhibiting ghrelin has been discussed as one way to treat obesity. But the new results, published this week in Cell Metabolism 1, suggest that drugs that block ghrelin may have unwanted effects on memory, says study author Alain Dagher of McGill University in Montreal, Canada. Ghrelin was already known to trigger hunger: people given a ghrelin injection will pile their plates higher when turned loose on an all-you-can-eat buffet. Patients with the rare genetic disorder Prader-Willi syndrome have abnormally high levels of ghrelin and sometimes eat without ever feeling sated; some evenrupture their stomachs. © 2008 Nature Publishing Group

By MICHELLE NIJHUIS Crows and their relatives — among them ravens, magpies and jays — are renowned for their intelligence and for their ability to flourish in human-dominated landscapes. That ability may have to do with cross-species social skills. In the Seattle area, where rapid suburban growth has attracted a thriving crow population, researchers have found that the birds can recognize individual human faces. John M. Marzluff, a wildlife biologist at the University of Washington, has studied crows and ravens for more than 20 years and has long wondered if the birds could identify individual researchers. Previously trapped birds seemed more wary of particular scientists, and often were harder to catch. “I thought, ‘Well, it’s an annoyance, but it’s not really hampering our work,’ ” Dr. Marzluff said. “But then I thought we should test it directly.” To test the birds’ recognition of faces separately from that of clothing, gait and other individual human characteristics, Dr. Marzluff and two students wore rubber masks. He designated a caveman mask as “dangerous” and, in a deliberate gesture of civic generosity, a Dick Cheney mask as “neutral.” Researchers in the dangerous mask then trapped and banded seven crows on the university’s campus in Seattle. In the months that followed, the researchers and volunteers donned the masks on campus, this time walking prescribed routes and not bothering crows. The crows had not forgotten. They scolded people in the dangerous mask significantly more than they did before they were trapped, even when the mask was disguised with a hat or worn upside down. The neutral mask provoked little reaction. The effect has not only persisted, but also multiplied over the past two years. Wearing the dangerous mask on one recent walk through campus, Dr. Marzluff said, he was scolded by 47 of the 53 crows he encountered, many more than had experienced or witnessed the initial trapping. The researchers hypothesize that crows learn to recognize threatening humans from both parents and others in their flock. Copyright 2008 The New York Times Company

By Peggy Curran For more than 50 years, Henry G. Molaison has been one of the most studied, famous and anonymous patients in the history of modern medicine. The 82-year-old man scientists have known only as HM died of heart failure Tuesday after decades in a Connecticut chronic care home, unaware of what he gave to science. “He never recognized me, even if I’d been with him all day” Brenda Milner, the pioneering neuropsychologist at the Montreal Neurological Institute who treated HM, said a few years ago. “He was always an extremely polite man. But I could pass him in the waiting room and he wouldn’t bat an eyelid. If you ever said anything, he would just say, ‘I’m sorry, I have a bit of trouble with my memory.’ ” Milner, 90, still works at the MNI, a respected doyenne whose ground-breaking research in human memory systems began in 1956 when Dr. Wilder Penfield and her mentor Dr. Donald Hebb sent her to Hartford to meet the man now known to generations of medical students as “H.M.” A 30-year-old assembly line worker, Molaison had suffered memory loss after parts of his temporal lobe were removed during experimental surgery to relieve severe epilepsy, which was causing him to have seizures and blackouts several times a week. © 2008 Canwest Publishing Inc.

By BENEDICT CAREY If a friend is someone who laughs at our stories, then a good friend is one who enjoys them even the second time around. But anyone who gasps with delight on hearing a story for the third time is faking it. Or, it’s a relative: some poor nephew Will or aunt Emily, sitting captive at the holiday table, being polite, perhaps covering a shudder of dread that life is caught in some endless loop where the punch lines never change. It is not an entirely irrational fear, either, according to new research published in the journal Psychological Science. “You hear people of all ages, not just elderly people, say, ‘Stop me if I’ve told you this before,’ ” said Nigel Gopie, a postdoctoral fellow at the Rotman Research Institute, in Toronto, who has a paper in the current issue of the journal on these memory lapses. “We often have a hard time remembering who we told things to, and clearly it starts early.” In their long study of memory, psychologists have made important distinctions between the short-term and long-term varieties. They have documented crucial differences between explicit memories, like for faces and vocabulary, and the implicit kind, like for driving skills. They have published hundreds of studies on autobiographical memory, false memories and so-called source memory — the ability to recall where a fact was learned, whether from the radio or a book, from a work colleague or the neighborhood gossip. Copyright 2009 The New York Times Company

Water on the brain VALERIE DEPRAETERE Salty sea water improves the long-term memory of crabs. Hector Maldonado and his colleagues at the University of Buenos Aires in Argentina have found that exposure to high salinity for six consecutive days helps the crab Chasmagnathus granultus - which usually lives on the shore of only slightly salty water - to learn1. Maldonado's group stressed the crabs by passing a screen over their heads, transiently masking the sunlight. A crab's reflex is to flee. But after repeatedly experiencing such eclipses without ensuing danger, a crab learns to ignore them. Crabs dunked in salty water need fewer exposures to the screen test to memorize the absence of danger, say the researchers. ..... 1.Delorenzi, A. High environmental salinity induces memory enhancement and increased levels of brain angiotensin-like peptides in the crab Chasmagnathus granulatus. The Journal of Experimental Biology 203, 3369–3379 (2000). .© Macmillan Magazines Ltd 2000 - NATURE NEWS SERVICE Nature © Macmillan Publishers Ltd 2000 Reg. No. 785998 England.

DALLAS –– Researchers at UT Southwestern Medical Center at Dallas have identified one of the key proteins involved in the establishment of the central nervous system. The researchers found that the protein, SynCAM, plays a major role in the formation of synapses, which are specialized junctions at which a neuron communicates with a target nerve cell. Neurons receive and send electrical signals over long distances within the body. The process of synaptic transmission drives communication between neurons in the brain and underlies all brain function. This is only the second study that cites the initial events leading to the formation of synapses in the central nervous system, said Dr. Thomas Biederer, a postdoctoral researcher in the Center for Basic Neuroscience and lead author of the study, reported in the Aug. 30 issue of Science. © 2002 The University of Texas Southwestern Medical Center at Dallas

By TOM SIEGFRIED / The Dallas Morning News Some people are born to win, some are born losers. Some people are born writers, others are born to be wild. But everybody is born to die, sooner or later. Death is as sure a thing as politicians' promising to cut taxes. Nobody knows, though, why people don't live forever. And nobody knows why we don't die a lot sooner than we do, either. On the one hand, aging seems to serve no useful purpose. Why should evolution have produced organisms that wear out and die? On the other hand, evolution is concerned only with producing fit offspring. So why do some animals – specifically, humans – live so long beyond their peak reproductive years? ©2002 Belo Interactive

Pitt study was conducted in collaboration with the Religious Orders Study Based at Rush Presbyterian-St. Luke’s Medical Center PITTSBURGH, – A study out of the University of Pittsburgh has uncovered a completely different mechanism behind mild cognitive impairment (MCI), an increasingly common memory problem that is thought to be a precursor to Alzheimer’s disease (AD). The results are surprising even to the researchers conducting the study and may explain why current medications don’t improve memory function effectively. Further, the findings may redirect research into many of the newer treatments designed to prevent memory problems. The study, published in today’s Annals of Neurology, found that in older people with MCI, the brain produces more choline acetyltransferase (ChAT), an enzyme that is important in memory and cognitive functions. The researchers believe this is the brain’s attempt to maintain normal function as the neurons that form communication lines to the brain’s memory center die. Strengthening their finding are autopsy results showing more than 60 percent of people who had MCI within a year before they died already had evidence of neurodegeneration that is seen in the early stages of AD.

By TOM SIEGFRIED / The Dallas Morning News You'll never read a best seller called The Joy of Smelling Skunks. It's a title that sounds as repulsive as skunk odor itself. Yet not everybody finds skunk odor so unpleasant. In fact, claims psychologist Rachel Herz, most odors are inherently neither pleasant nor unpleasant. Odors are like the ABCs; you have to learn them, and you usually learn them young. You might even learn to like the smell of skunks. Dr. Herz, of Brown University in Providence, R.I., confesses her feelings for Pep� Le Pew in the latest issue of Cerebrum, a quarterly published by The Dana Forum on Brain Science – an appropriate venue, as smell is, after all, the shortest route to the brain. A bit of the brain actually protrudes into the nostrils, in the form of small nerve cells that extend tiny cilia into the mucus that covers the nasal membrane. The cilia receive chemical messages that come from the air in the form of molecules carrying the essence of odors. ©2002 Belo Interactive

Chapters 17-18. Learning and Memory