Snippets of Science

Neuroscience: The impact of violent video games

Researcher Dr Vincent Matthews and his team from Indiana University specialize in studying the effects of media violence. Their most recent investigation involved a group of 28 young, male students, assigned to either play violent or non-violent video games everyday for a period of 1 week.The students selected had no prior experience in video gaming. The participants were subjected to MRI scans before and after their gaming experience, while they carried out a series of tasks involving emotional or non-emotional content. 

The MRI scans revealed that the students who played the violent video game had much lower brain activity in regions governing emotions, attention and inhibition of impulses. Dr Matthews explains, “Behavioral studies have shown an increase in aggressive behavior after violent video games, and what we show is the physiological explanation for what the behavioral studies are showing.”

A week after the investigation was completed, the participants were brought back in for another scan. The results of the post-investigation scan showed that a week of no exposure to the violent game resulted in a reversal of brain activity levels similar to the norm, although levels was not quite the same as before the experiment.

During the MRI scan, the male students were presented with violent and non-violent terms in different colors. They were asked to identify the color of the word instead of its meaning, a variation of the typical Stroop effect psychological test. Participants would have the tendency to process the meaning of the word before they are able to identify the color it is written in.

Participants who played non-violent games displayed increased brain activity in the regions involved in emotional responses, when they were shown words with violent indications. As expected, those who were exposed to violent gaming had significantly lower activity levels in comparison to their control scores taken at the start of the experiment.

Though none of these changes appear to be permanent, the study of the brain’s response after regular exposure to violent video games could potentially be useful in determining the impact such activities have on young, developing minds.

(Source: TIME)


Psychology: Avoiding PTSD - To counsel or not to counsel?

Surviving severe natural disasters such as an earthquake and a tsunami is expected to impact a person both mentally and emotionally. However, medical personnel directly involved in the recent traumatic event in Japan were advised not to provide immediate counseling to survivors, after latest research suggests the lack of counseling support might be more beneficial in countering post-traumatic stress disorder (PTSD) development.

Dr David Forbes of the Australian Center for Posttraumatic Mental Health indicates that PTSD is caused by “an increased engraving of the horrifying memories in the brain, reducing their potential to fade.”. From as far back as the 1980s, some psychologists and counselors begun to consider the possibility that people could be spared from developing PTSD if they were not required to discuss the experience immediately after going through it.

The decision not to counsel the Japan earthquake survivors was sanctioned by Japanese mental health authority officials, after an international review revealed that only 5-10% of natural disaster survivors develop PTSD. A separate investigation published recently also concluded that there was no evidence to indicate that immediate intervention would prevent PTSD.

Researcher Justin Kennard from the University of Queensland believes that middle ground in this debate lies in a specialized version of cognitive behavioral therapy (CBT). This therapy technique involves 4-12 therapy sessions that are administered at least a month after the traumatic event. He postulates that such a time period is sufficient for the survivors to internalize and deal with the emotional impact in their own ways, leaving only those that at most risk to PTSD easily identifiable.

(Source: newscientist.com)


Neuroscience: The cause of obesity - the Brain?

It seems that whenever we muster up the resolve to lose weight, saying no to that slice of chocolate pie for dessert or choosing a salad for lunch instead of a cheeseburger, we start losing our minds. Literally. We find ourselves thinking and craving certain high-fat or high-sugar foods all hours of the day. However, with diseases and the statistic that two-thirds of American adults are classified as overweight looming large in our minds, we endure and starve ourselves with the hope of losing pounds. Dieting would be a lot easier if we did not have to deal with food cravings, so the question that begs to be answered is, why do our bodies subject us to torment when we are trying to keep it lean and healthy? Neurobiologists believe that the brain has all the power, and sometimes no matter how much we set our hearts to losing weight, one signal from the brain is all it takes for us to chomp down that french fry. 

The brain is not an evil, obesity-encouraging machine, it was simply programmed early in evolution to be obsessed with the notion of uncertainty when it comes to our next meals. As such, our bodies are easily swayed toward hunger, as our brain focuses on getting us to eat and store fat. Hans-Rudolf Berthoud, an expert in the neurobiology of nutrition from the Pennington Biomedical Research Center in Baton Rouge Louisiana comments, “The system has evolved to defend against the slightest threat of weight loss.”

Adipose tissue releases a hormone called leptin, that journeys across the body to the brain region known as the hypothalamus. Once there, it stimulates the hypothalamus to induce a reduction in hunger so that we may stop eating. Sounds like a great molecule for weight loss induction, right? It did not work. With more adipose tissue, obese humans produce higher levels of leptin than humans of normal weight. The leptin injections during clinical trials were of insignificant impact, as the brain seemed to pay attention to the lower levels of leptin signaling the need to eat, as compared to the overwhelmingly high levels of leptin injected to reduce hunger.

This spurred researchers to look for the counter-argument. Ghrelin, a molecule produced by the gut, stimulates a hunger reaction in the hypothalamus. A study by a team from the University of Washington revealed that ghrelin levels rise just before a meal, but falls rapidly after. Scientist have just began the usage of Grehlin in animal models, so it appears clinical trials are still a number of years away. University of Washington endocrinologist David Cummings compared ghrelin levels in people who had achieved considerable weight loss through dieting versus those who underwent gastric bypass surgery. Gastric bypass surgery results not only in a reduction of stomach capacity, but also damages ghrelin-producing cells. He discovered that with increased weight loss by the dieters, there was a corresponding increase in ghrelin levels, as if the body was directing the brain to produce hunger signals so as to regain the weight lost. This was never observed in surgical patients, most of whom never experienced increased appetites and had no problems maintaining their weight loss.

Perhaps the key lies in our circadian rhythm and sleep cycles? Scientists have shown that mice carrying a mutated version of the Clock gene, a gene that is vital for the maintenance of the body’s circadian rhythm, failed to follow the eat-by-day and sleep-by-night ritual. This resulted in them becoming grossly overweight and diabetic. Given that most of us live by mantras of society that encourage little sleep, it might be the lack of sleep that is wrecking our circadian rhythm, and has got us piling on the weight. 

Another angle that must be explored is a psychological one. Irregardless of the amount of sleep obese people get, maybe this group of people simply derive more pleasure from eating and are more dependent on it. Clinical psychiatrist Eric Stice of the Oregon Research Institute conducted fMRI brain scans while subjects were drinking a chocolate milkshake. The scans revealed that obese subjects had greater activation levels of the gustatory cortex and the somatosensory region, areas involved in the sensory experience of food, as compared to leaner volunteers. In addition, there was decreased activation in the striatum, an area that is covered in dopamine neurons and functions to respond to stimuli associated with rewards. Stice is convinced that the reduced pleasure results in the obese subjects requiring more of their “drug” to attain the same level of rewarding feelings as lean subjects. Drexel University psychologist Michael Lowe took fMRI scans of two groups of volunteers, one that followed strict diets and another group that ate whatever they fancied. The brain scans of the dieting group displayed increased activation in brain regions associated with desire and an expectation of reward. Interestingly enough, the milk shake also seemed to make them hungrier. Lowe says, “These chronic dieters may actually have a reason to restrain themselves, because they are more susceptible than average to overeating.”

Research by neurobiologist Tracy Bale of the University of Pennsylvania, has shown that neural pathways associated with stress responses are directly linked to brain regions involved in the seeking of rewards. As such, she strongly believes in a neurological basis behind stress eating. “It’s because those stress pathways in the limbic system feed into reward centers, and they drive reward seeking behaviors. What that tells us is that in addition to drug companies trying to target appetite, they need to look at reward centers. We’re not necessarily fat because we’re hungry but because we’re looking something to deal with stress.”

Whether obesity is simply a situation of mind over matter or an underlying metabolic fault, scientists continue to be baffled on how best to deal with this burgeoning issue. One thing remains certain, they remain undeterred in their search for a safe and effective weight control treatment.

(Source: discovermagazine.com)


Addiction: Nature AND Nurture

Drug or alcohol abuse is a slippery slope, and addiction awaits at the bottom of that slope with open arms. Once someone starts going down, it will most certainly be the fight of their lives to get back to higher ground. For every person that manages to overcome dependence, there are so many others whom addiction drives to an early grave. The 2008 National Survey of Drug Use and Health has determined that 46% of Americans have used an illegal drug at least once in their lives. Despite this, the number of drug addicts in society remains a minority. Is there a factor, present in some groups of people and not others, that intensifies the challenge of overcoming addiction?

Psychiatric patients suffering from mood, anxiety and personality disorders have been identified by clinicians to be highly at risk of turning into addicts. The National Institute of Mental Health’s Epidemiologic Catchment Area Study has tabulated a three-fold likelihood that mental health patients also battle addictive disorders. The converse argument also seems true, with 60% of substance abusers having been identified to suffer from mental illness. At the end of the day, it remains unclear if mental illness prediposes someone to addiction, or vice versa. Although, the link between suffering from a mental illness and the usage of an abusive substance might indicate a self-medicating belief by addicts against their misery. 

The major areas of the brain involved in mental illnesses are often the same ones that control alcohol or drug-influenced mood and behavior. Patients suffering from depression or anxiety turn to alcohol or sedatives, activating brain pathways that alleviate the effects of their psychiatric state. Unfortunately, these substances are not proper anti-depressants, eventually leading to addiction and compounding the severe depression suffered by patients.

A recent study by Dr Nora Volkov of the National Institute on Drug Abuse, demonstrated that non-addicts have a much higher number of dopamine receptors in the brain’s reward pathway, as compared to addicts. Dopamine is a neurotransmitter that is crucial for processing signals of pleasure or desire. It also calls on the brain to pay attention to important stimuli. When Dr Volkov gave both groups a stimulant, non-addicts found the stimulant aversive while addicts experienced pleasure as a result of it. This indicates a possibility that addicts might have been born with or developed a stunted brain reward system, preventing them from placing everyday happiness on the same level of pleasure as the high obtained from a substance.

Levels of dopamine receptor, D2, are observed to decline in primates that have been placed in stressful social situations. Dr Volkov has noted that together with an access to drugs, this decline in D2 levels results in these primates becoming aggressive cocaine users. This behavior calls into question the power of genetic predisposition toward addiction, given the low genetic risk of addiction in animals. As such, the possibility also remains that any human being can become an addict if circumstances are encouraging. Since drug use often begins during adolescence, a period of high brain plasticity, it is crucial for aggressive treatment against addiction to take place then, before the fate of addiction is sealed.

Source: The New York Times


Psychology: Middle class looters during the UK riots

With millions of dollars in property damage and extensive injuries to some protestors, the 2011 UK riots captured the attention of the world earlier this week. As with every violent demonstration, break-ins and looting was a common sight. What was unexpected were the kinds of people who doing the looting, they ranged from a millionaire’s daughter to a school teaching assistant, hardly the types one would assume to be hard up. Some of these culprits have also openly expressed regret toward committing these crimes. It drives one to wonder what was the underlying psyche that lead these people to loot.

A behavioral scientist from the University of Chicago, Ayelet Fisbach, believes it’s simply about going with the flow. “It’s a classic demonstration of the power of the situation. People in a group follow the group’s norms.”

Further explained, it seems that when normal people find themselves in abnormal situations or groups, they give up their personal identity and values. This is process is deemed deindividualization. According to Fisbach, without personal identity and values, people lose track of social responsibility, thinking little when engaging in anti-social behavior.

Clarke McCauley of Bryn Mawr College believes that the urge to keep up with your peers might also be a motivating factor. “If you watch others looting and getting richer, you are seeing them getting ahead of you….It’s the fear of falling behind.”

(Source: newscientist.com)


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