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The Brain
Written and researched by Bob Murray, PhD
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Does Being Fat Lead to Alzheimer's Disease?
September 4, 2002
Eating more calories and fats may contribute to an increased risk of Alzheimer's disease (AD) in some people, according to an article in the latest issue of The Archives of Neurology.
According to background information given, significantly reduced calorie diets have been associated with longer life spans in mice and rats. Researchers believe that the relationship is a result of the production of fewer free radicals, destructive molecules formed during the breakdown of food and oxygen in cells. Free radicals damage cells and may increase the damage done by beta amyloids, the glue-like particles found in the brains of people with AD.
Jose A Luchsinger MD, of Columbia University, New York, and colleagues studied the association between caloric intake and AD in 980 elderly individuals without AD at the start of their study. The researchers followed these patients for an average of 4 years. They recorded how many calories they ate and tested for the presence of the apolipoprotein E (APOE) epsilon 4 allele, a gene that has been associated with AD.
During the study, 242 patients developed AD, and 28 percent tested positive for the APOE epsilon 4 gene. The average daily caloric intake of the women studied (67 percent of the study population) was 1,267 kcals. Men consumed an average of 1,316 kcals per day. Average daily fat consumption in both groups was 38 grams.
The researchers divided the study group into four groups depending on how many calories were consumed daily. The group that consumed the most calories had a 50 percent greater chance of developing AD.
The researchers also looked at the effect of the APOE epsilon 4 gene. Of the participants, 263 tested positive for the APOE epsilon 4 gene, and among them, those who consumed the most calories had a 2.3 times greater chance of developing AD compared to those who ate the fewest calories.
The authors write that "Calorie restriction may also decrease [nerve cell] death and increase expression of neurotrophic [nerve-protecting] factors in the brain. Reduced calorie intake can increase the brain's capacity for plasticity and repair in neurodegenerative disorders, including AD."
The researchers conclude: "Our analyses of 242 cases of incident AD... revealed that the risk of AD is associated with higher total calorie intake and fat intake in individuals [with] the APOE epsilon 4 [gene]. In individuals without the APOE epsilon 4 [gene], calorie and fat intake were not associated with risk of AD."
Here is yet another example of how a genetic propensity needs to be triggered by the person's behavior in order to bring on illness, something we have been stressing for some time. AF
Read more in The Archives of Neurology
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Does PEPSI Make You Feel Emotional?
September 4, 2002
Consumers reading a brand name do not treat it like any other word -- instead they activate parts of the brain normally used to process emotions, the study claims. The researchers used computer testing to check the reactions of 48 students at the University of California in Los Angeles.
Dr Eran Zeidel, who led the study, suggests that the arrival of the "brand" in the past century has prompted brain evolution. The students were told to watch a computer screen, and various words were flashed up, either on the left hand side or right hand side, and in capitals or lower case letters.
The words displayed were either common nouns such as "river" or "tree", brand names such as Sony or Compaq, or "non-words" such as "beash" and "noerds." The students were asked to hit a button as soon as they recognised the word as real. They spotted the common nouns most quickly, followed by the brand names and then the non-words.
The common nouns were identified more quickly when displayed on the right hand side of the screen. This suggests, as expected, that the left hand side of the brain is highly involved in processing them. However, the reverse was true when the brand names were displayed, with the subjects spotting them more quickly when they were displayed on the left. This probably means that the right hand side of the brain -- more commonly associated with the processing of emotions -- was more heavily involved.
Dr Zaidel said: "It is surprising. The rules that apply to word recognition in general do not necessarily apply here."
According to an advertising specialist, this confirms the essence of how brands are supposed to work. Robert Jones, head of consulting at the brand strategists Wolff Olins in London, told New Scientist "A brand's power is that it conjures up a whole range of associations and ideas, which are primarily emotional."
Read more in New Scientist
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Brain's Cheat Detector is Revealed
September 4, 2002
"We think (this facility) develops in all normal individuals, and that it develops in part because our brains were selected to develop this competence," says John Tooby at the University of California, Santa Barbara.
Tooby and his colleagues studied a man who suffered accidental damage to the limbic system, a brain region involved in processing emotional and social information. RM, as he is referred to, performed as well as other people on one set of reasoning problems, did much worse on problems specifically designed to test reasoning about social exchanges.
At its simplest, social exchange runs along the lines of "you scratch my back and I'll scratch yours." Previous work has shown that people, and some animals, are extremely good at keeping a check of who owes whom within a group -- and at spotting and punishing cheaters.
Researchers had proposed that general reasoning abilities could account for this. But RM's deficit suggests that detecting social cheaters depends on specialized neural circuitry, the team says.
Their conclusion is "robust," says Nigel Nicholson, an evolutionary psychologist and Director of the Centre for Organizational Research at the London Business School. "It's essential we have trusting relationships with people in communities where we are highly interdependent for survival and reproduction. Cheat detection is very important," he adds.
The first problems given to RM and the 37 non-brain-damaged controls concerned so-called precaution rules. For example: "If you work with toxic chemicals, you have to wear a safety mask." The second tested social contracts, for example: "If you go canoeing on the lake, you have to have a clean bunk house."
RM recorded a score of 70 per cent on the precaution rule tests -- the same as the controls. But he scored only 39 per cent on the social contract tests, compared with 70 per cent for the non-brain damaged people. Identical tests on two other people with brain damage similar to RM's, but with a slightly different pattern of damage, showed that their social contract reasoning was unimpaired.
"RM's differential impairment indicates that being able to detect potential cheaters may be a separable component of the human mind," the researchers conclude. However, if a region of the brain has evolved to specialise in cheat detection, it should be present in all people, the team reasoned.
Most experiments are performed on people living in modern, western societies, so the team studied people living in traditional, non-developed communities in the Amazonian region of Ecuador. They found that these people were equally proficient at social exchange tasks, even when the problems concerned social rules that were unfamiliar to them.
"What is quite amazing about their performance on cheater detection is that it flies in the face of all ordinary ideas about learning a higher level cognitive skill," Tooby told New Scientist. "People are just as good at utterly unfamiliar rules as they are with rules that are personally and culturally highly familiar."
Read more in New Scientist
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Newborns Can Detect Eye Contact
July 7, 2002
This ability probably helps infants to establish human links and to develop social skills in later life, say scientists. Being able to make eye contact is arguably one of the major foundations for social skills. It is also one of the things that makes us uniquely human.
The fact that healthy babies can do this at such an early age suggests the response is in-built rather than learned. The new research was carried out by an Anglo-Italian team. They showed paired photographs of faces to infants between two and five days old. In one photograph, the eyes were averted. In the other the eyes looked directly forward. The researchers found that the babies looked longer at faces they were able to make eye contact with. Their eyes also looked forward more.
In a second experiment, carried out at Birkbeck, University of London, researchers measured electrical activity in the brain of four-month-old infants. A device called a geodesic sensor net allowed them to study the infant's brain response to the same photographs. The babies showed enhanced processing of the faces with a direct gaze.
"Our research presents the most compelling evidence to date that we are born prepared to detect socially relevant information," said lead researcher Dr Teresa Farroni.
The work raises the possibility of being able to detect if a child is at risk of certain developmental disorders by showing them photographs of faces. In conditions like autism the ability to empathize with others may be impaired. Eye contact too can be affected.
David Potter of the UK National Autistic Society said there was evidence that individuals with autism used different neural circuitry to process faces. "What appears to be a simple perceptual task is difficult for individuals with autism," said. "Research is under way to try to understand the differences in the brains of people with autism which explain this difficulty. If affected individuals spend reduced amounts of time processing faces then they are also failing to develop the social interaction skills that open up the full realm of social life."
Eye contact is just as important in adult relationships as it is with infants. BM
Read more in Proceedings of the National Academy of Sciences
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Damage to the Hippocampus Impairs Working Memory
June 24, 2002
Researchers at Yale University Medical School have discovered that damage to the hippocampus (a part of the limbic system in the central brain which plays a part in regulating emotions and memory) can impair short-term, or "working," memory. The part of the brain concerned with working memory is found in the prefrontal cortex, just back from the forehead. Rats who had suffered neonatal damage to the hippocampus could not perform tasks which required the use of working memory as well as rats who had not. In humans the hippocampus can be damaged in a number of ways which include maternal stress passed on to the unborn infant and abuse and trauma in the early years of life.
Read more in American College of Neuropsychopharmacology
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Brain Scan Predicts Path of Depression
June 24, 2002
Researchers at the University of California, Los Angeles have detected signs of changes to patients' brain waves weeks before they showed any visible benefits from taking medication. The scientists, led by Dr Ian Cook, say the method could minimize the waste of drugs on patients who are unlikely to respond positively. This is doubly important, as the drugs are expensive and can have serious side effects.
Dr Cook said: "This is the first study to detect specific changes in brain wave activity that precede the clinical changes in a way that can usefully predict response."
Many depressed patients do not respond to the first medication they try, or any. Since it takes several weeks for an effective treatment to produce clear improvement, doctors often wait six to 12 weeks to decide that a particular drug just isn't right for that patient and move on to another treatment. Recent studies have also shown that patients may respond to dummy pills in much the same way they respond to antidepressants.
The scientists used an EEG (electroencephalogram) to measure electrical activity in an area of the brain called the prefrontal cortex, which is involved in judgment and motivation. They detected changes in some cases just two days after patients began taking medication, even though clear clinical differences did not become apparent for about four weeks.
In total, 51 patients with acute depression took part in the study. They were given either Prozac, Effexor or a dummy pill. Overall, about 50% of the volunteers responded to one of the two drugs, while 38% responded to the placebo. EEG scans picked up changes in activity in the prefrontal cortex in patients from all three groups who responded positively.
However, the changes took longer to appear in those patients who responded to the dummy pill, and when they did come, they were different. Patients who responded to medication registered a decrease in prefrontal cortex activity, while those who responded to the placebo registered an increase in activity. The researchers wrote that their findings may well one day revolutionize the whole basis of drug therapy for depression.
Read more in Neuropsychopharmacology
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Heavy Drinkers Stimulated by Alcohol
June 24, 2002
Researchers from the University of Chicago looked at whether people get a sedative or a stimulatory effect from alcohol said those in the latter category are more likely to drink heavily.
In the study, published in the journal Alcoholism: Clinical & Experimental Research, researchers looked at how drinkers were affected by alcohol. Drinkers' reported their moods after alcohol, and they were tested to see how their body reacted to moderate-to-high doses of alcohol.
Thirty-four drinkers aged between 24 and 38 were studied. Half drank five or less alcoholic drinks per week while the heavy drinkers regularly had 10 or more drinks. They were either given two different doses of alcohol (the equivalent of two or four drinks) or a drink which just had an alcohol smell and taste. They then filled out questionnaires, and their heart rate, blood alcohol and cortisol (a stress hormone, which is also a factor in depression) levels were tested.
Heavy drinkers showed increased stimulation and euphoria when blood alcohol concentrations rose. They also enjoyed the experience and wanted to carry on drinking. Light drinkers showed increases in sedation and did not report stimulation or positive mood changes. They also had increases in cortisol levels after drinking, whereas the heavy drinkers did not.
Andrea King, a psychologist and assistant professor in the university's department of psychiatry who led the research, said: "A person who feels enhanced euphoria and stimulation when drinking alcohol may be more likely to continue to consume alcohol during the drinking bout. Since they may be more sensitive to the rewarding effects of alcohol, they may be more vulnerable to developing habitual, heavy drinking patterns which would increase their chances of having eventual alcohol problems and negative consequences related to drinking."
Raymond Anton, professor of psychiatry and scientific director of the Alcohol Research Center at the Medical University of South Carolina, said in a separate statement that: "Alcohol works on different brain chemicals that may be more or less sensitive to various amounts of alcohol in the blood. It is likely that different people have different brain chemistries, making them more or less sensitive to one or the other of these effects, stimulation or sedation, from a given dose of alcohol."
Read more in Alcoholism: Clinical & Experimental Research
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Abused Kids See Emotion Differently
June 24, 2002
Because people recognize the same emotions across languages and cultures, psychologists have long suspected that a person's ability to perceive basic emotions is innate.
However, a new study published in the Proceedings of the National Academy of Sciences suggests that experience can alter the way people see emotions. Led by University of Wisconsin-Madison psychologist Seth Pollak, the study examined how children categorize facial expressions as happy, sad, angry or fearful based on one particular emotional experience -- physical abuse.
Studying children who had been abused, Pollak says, offered an opportunity both to examine the effects of atypical experience on how children think about emotions and to possibly identify new interventions that could help abused children more effectively manage resulting behavioral problems.
For this study, Pollak invited both abused and non-abused children, 8 to 10 years old, to his Child Emotion Research Laboratory. There, they played computer "games" that presented digitally morphed photos of facial expressions that ranged from happy to fearful, happy to sad, angry to fearful, or angry to sad. While some of the faces expressed a single emotion, most were blends of two emotions.
In one of the games, the children saw a single face and had to choose which emotion it expressed the most. Because many images were a composite of emotions, this task allowed the researchers to determine how the children perceived different expressions.
Pollak, along with colleague Doris Kistler from the Waisman Center, found that the two groups of children did categorize emotional expressions differently. While both abused and non-abused children generally responded the same way to expressions showing mostly happiness, sadness or fear, abused children identified more faces as being "angry," rather than fearful or sad. Even though an expression would show, for example, 60 percent fear and 40 percent anger, abused children would identify the latter emotion.
"There aren't differences in how the children recognize pictures of faces, but in how they categorize those faces. The abused children were more sensitive to anger," Pollak says. "Experience can shift where a person draws the boundary of a particular emotion, and this idea runs counter to claims that boundaries for emotions are innate."
Pollak says that the neural processes the brain uses to perceive and categorize emotion might be innate but that how people actually perceive and understand expressions of emotion can be shaped by experience.
Pollak's latest finding confirms the results of one of the psychologist's earlier studies, which found that children who were abused exhibited more brain electrical activity than non-abused children when shown angry faces, as opposed to other facial expressions.
"It may be the case that physically abused children develop a broader category of anger because it's adaptive for them to notice when adults are angry," he says.
But while this sensitivity could be protective in a threatening environment, it could be disadvantageous in others. An abused child might over-interpret a social cue, such as an accidental ball toss during recess, to be hostile. As a result, the child might try to protect himself by lashing out, calling names or exhibiting other inappropriate behaviors. By recognizing an abused child's sensitivity to cues of anger, Pollak says, psychologists may be able to help these children respond more appropriately.
Read more in Proceedings of the National Academy of Sciences
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Mother's Antenatal Anxiety Leads to Behavior Problems in Children
June 10, 2002
According to researchers led by Dr Thomas O'Connor of the Institute of Psychiatry in London a mother's antenatal anxiety can show up in her child's behavior problems up to four years on. In a longitudinal study of more than 7,000 women they found that behavioral problems showed up in up to 95% of the offspring of anxious prenatal mothers. They speculate that there could be a direct link between maternal mood on foetal brain development, which affects the behavioral development of the child.
Read more in the British Journal of Psychiatry
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Binge Drinking Causes Rapid Damage
May 3, 2002
The finding, published in the journal Alcoholism: Clinical & Experimental Research, could have implications for the growing legions of young people all over the Western world who binge drink.
It has commonly been thought that brain damage, or neurodegeneration, occurs not when a person is drunk, but over a longer period when the brain has to cope with alcohol withdrawal. However, a new study on rats has shown that just two days of binge drinking is enough to cause damage to an area of the brain called the olfactory bulb, which is responsible for smell.
Damage to other regions of the brain occurred after just four days of binge drinking.
Researcher Dr Fulton Crews, Director of the Center for Alcohol Studies at the University of North Carolina, said most previous research had focused on the long term effect of alcohol. He said the study may show "an important early process in the progression from experimentation with alcohol to addiction.".
Professor Michael Collins, of Loyola University Chicago, said: "Certainly this has implications for a college student contemplating a weekend of binge drinking. It is possible that neuronal degeneration after a couple of days of heavy intoxication in the rat might translate to the human drinker who is not even a chronic alcohol abuser."
He added that there was no firm proof of this yet and brain imaging was needed to determine whether short-term binges would permanently damage neurons in humans.
Previous research by a team from the same university found that adolescent brains may be particularly vulnerable to the effects of alcohol. The results suggested that binge drinking during adolescence leads the brain to respond more sensitively to alcohol in the future.
Separate research has also found that children of alcoholics tend to exhibit attention deficit disorder, hyperactive tendencies and unruly behaviour. These children are also more likely to develop significant alcohol problems, such as abuse or dependence. Scientists believe these characteristics may be due to underlying differences in brain chemistry and physiology, which may be due to genetic or environmental factors.
Campus drinking has recently is at an all-time high. However, proposed programs that increase education about the dangers of alcoholism don't get to the root of the problem. The real question is, how does society identify and reduce the stressors and depression in teenagers and young adults that underlie this behavior?
Read more in Alcoholism: Clinical " Experimental Research
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About the Author
Dr Bob Murray is a widely published psychologist and expert on emotional health and optimal relationships. Together with his wife and long-term collaborator Alicia Fortinberry, he is founder of the highly successful Uplift Program, and author of Raising an Optimistic Child (McGraw-Hill, 2006) and Creating Optimism (McGraw-Hill, 2004).
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