Do you hear what I hear?

 
(Medical Xpress) -- In both animals and humans, vocal signals used for communication contain a wide array of different sounds that are determined by the vibrational frequencies of vocal cords. For example, the pitch of someone's voice, and how it changes as they are speaking, depends on a complex series of varying frequencies. Knowing how the brain sorts out these different frequencies—which are called frequency-modulated (FM) sweeps—is believed to be essential to understanding many hearing-related behaviors, like speech. Now, a pair of biologists at the California Institute of Technology (Caltech) has identified how and where the brain processes this type of sound signal.

Their findings are outlined in a paper published in the March 8 issue of the journal Neuron.

Knowing the direction of an FM sweep—if it is rising or falling, for example—and decoding its meaning, is important in every language. The significance of the direction of an FM sweep is most evident in tone languages such as Mandarin Chinese, in which rising or dipping frequencies within a single syllable can change the meaning of a word.

In their paper, the researchers pinpointed the brain region in rats where the task of sorting FM sweeps begins.

"This type of processing is very important for understanding language and speech in humans," says Guangying Wu, principal investigator of the study and a Broad Senior Research Fellow in Brain Circuitry at Caltech. "There are some people who have deficits in processing this kind of changing frequency; they experience difficulty in reading and learning language, and in perceiving the emotional states of speakers. Our research might help us understand these types of disorders, and may give some clues for future therapeutic designs or designs for prostheses like hearing implants."

This diagram shows areas in the midbrain region where direction- selective neurons were found.Credit: Guangying Wu/Caltech

The researchers—including co-author Richard I. Kuo, a research technician in Wu's laboratory at the time of the study (now a graduate student at the University of Edinburg)—found that the processing of FM sweeps begins in the midbrain, an area located below the cerebral cortex near the center of the brain—which, Wu says, was actually a surprise.

"Some people thought this type of sorting happened in a different region, for example in the auditory nerve or in the brain stem," says Wu. "Others argued that it might happen in the cortex or thalamus. "

To acquire high-quality in-vivo measurements in the midbrain, which is located deep within the brain, the team designed a novel technique using two paired—or co-axial—electrodes. Previously, it had been very difficult for scientists to acquire recordings in hard-to-access brain regions such as the midbrain, thalamus, and brain stem, says Wu, who believes the new method will be applicable to a wide range of deep-brain research studies.

In addition to finding the site where FM sweep selectivity begins, the researchers discovered how auditory neurons in the midbrain respond to these frequency changes. Combining physical measurements with computational models confirmed that the recorded neurons were able to selectively respond to FM sweeps based on their directions. For example, some neurons were more sensitive to upward sweeps, while others responded more to downward sweeps.

"Our findings suggest that neural networks in the midbrain can convert from non-selective neurons that process all sounds to direction-selective neurons that help us give meanings to words based on how they are spoken. That's a very fundamental process," says Wu.  

Wu says he plans to continue this line of research, with an eye—or ear—toward helping people with hearing-related disorders. "We might be able to target this area of the midbrain for treatment in the near future," he says.

More information: The Neuron study, "The Generation of Direction Selectivity in the Auditory System," was funded by grants from the Broad Fellows Program in Brain Circuitry of the Broad Foundation and Caltech.

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Men respond more aggressively than women to stress and it's all down to a single gene

The pulse quickens, the heart pounds and adrenalin courses through the veins, but in stressful situations is our reaction controlled by our genes, and does it differ between the sexes? Australian scientists, writing in BioEssays, believe the SRY gene, which directs male development, may promote aggression and other traditionally male behavioural traits resulting in the fight-or-flight reaction to stress.

Research has shown how the body reacts to stress by activating the adrenal glands which secrete catecholamine hormones into the bloodstream and trigger the aggressive fight-or-flight response. However, the majority of studies into this process have focused on men and have not considered different responses between the sexes.

"Historically males and females have been under different selection pressures which are reflected by biochemical and behavioural differences between the sexes," said Dr Joohyung Lee, from the Prince Henry's Institute in Melbourne. "The aggressive fight-or-flight reaction is more dominant in men, while women predominantly adopt a less aggressive tend-and-befriend response."

Dr Lee and co-author Professor Vincent Harley, propose that the Y-chromosome gene SRY reveals a genetic underpinning for this difference due to its role in controlling a group of neurotransmitters known as catecholamines. Professor Harley's earlier research had shown that SRY is a sex-determining gene which directs the prenatal development of the testes, which in turn secrete hormones which masculinise the developing body.

"If the SRY gene is absent the testes do not form and the foetus develops as a female. People long thought that SRY's only function was to form the testes" said Professor Harley. "Then we found SRY protein in the human brain and with UCLA researchers led by Professor Eric Vilain, showed that the protein controls movement in males via dopamine."

"Besides the testes, SRY protein is present in a number of vital organs in the male body, including the heart, lungs and brain, indicating it has a role beyond early sex determination," said Dr Lee. "This suggests SRY exerts male-specific effects in tissues outside the testis, such as regulating cardiovascular function and neural activity, both of which play a vital role in our response to stress."

The authors propose that SRY may prime organs in the male body to respond to stress through increased release of catecholamine and blood flow to organs, as well as promoting aggression and increased movement which drive fight-or-flight in males. In females oestrogen and the activation of internal opiates, which the body uses to control pain, may prevent aggressive responses.

The role of SRY regulation of catecholamines also suggests the gene may have a role in male-biased disorders such as Parkinson's disease.

"New evidence indicates that the SRY gene exerts 'maleness' by acting directly on the brain and peripheral tissues to regulate movement and blood pressure in males," concluded Lee. "This research helps uncover the genetic basis to explain what predisposes men and women to certain behavioural phenotypes and neuropsychiatric disorders."

More information: Lee. J, Harley. V, “The male fight-flight response: A result of SRY regulation of catecholamines?” Bioessays, Wiley-Blackwell, March 2012, DOI: 10.1002/bies.201100159

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Mathematical model describes the collaboration of individual neurons

How do neurons in the brain communicate with each other? One common theory suggests that individual cells do not exchange signals among each other, but rather that exchange takes place between groups of cells. Researchers from Japan, the United States and Germany have now developed a mathematical model that can be used to test this assumption. Their results have been published in the current issue of the journal PLoS Computational Biology.

A neuron in the neocortex, the part of the brain that deals with higher brain functions, contacts thousands of other neurons and receives as many inputs from other neurons. Previously, it has been very difficult to use measured signals to interpret the way the cells work together. Scientists at the RIKEN Brain Science Institute (BSI) in Japan have now joined forces with researchers at the Forschungszentrum Jülich, Germany, and MIT in Boston, USA, to develop a mathematical model that can clarify the way neurons collaborate.

"From the many signals measured in parallel, the novel method filters the information on whether the neurons communicate individually or as a group", explains Dr. Hideaki Shimazaki from BSI. "Furthermore it takes into account that these groups of cells are not fixed but, instead, can organize themselves flexibly within milliseconds into groups of different composition, depending on the current requirements of the brain."

Prof. Sonja Grün from Forschungszentrum Jülich hopes that the method can help researchers to prove the existence of dynamic cell assemblies and clearly assign their activities to certain behaviors. The scientists already demonstrated that neurons work together when an animal anticipates a signal, which may allow it to have a more rapid or more sensitive response.

In future, the scientists hope to learn how to use their methods on the signals recorded from hundreds of neurons simultaneously. This would raise the probability of observing cell assemblies involved in planning and controlling behavior.

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Want to limit aggression? Practice self-control

Feeling angry and annoyed with others is a daily part of life, but most people don't act on these impulses. What keeps us from punching line-cutters or murdering conniving co-workers? Self-control. A new review article in Current Directions in Psychological Science, a journal of the Association for Psychological Science, examines the psychological research and finds that it's possible to deplete self-control—or to strengthen it by practice.

Criminologists and sociologists have long believed that people commit violent crimes when an opportunity arises and they're low on self-control. "It's an impulsive kind of thing," says Thomas F. Denson, a psychologist at the University of New South Wales. He cowrote the new article with C. Nathan DeWall at the University of Kentucky and Eli J. Finkel at Northwestern University. For the last 10 years or so, psychologists have joined this research, using new ways of manipulating self-control in experiments; they have found that, indeed, self-control and aggression are tightly linked.

A psychological scientist can deplete someone's self-control by telling the subject they're not allowed to take one of the cookies sitting in front of them. Studies have found that, after people have had to control themselves for a while, they behave more aggressively. In a 2009 study, after someone's self-control was depleted, they were more likely to respond aggressively to nasty feedback that ostensibly came from their husband or girlfriend. Specifically, they assigned their partner to hold a painful yoga pose for longer.

On the other hand, it's also possible to practice self-control the same way you would practice the piano. In Denson's experiments, he has people try to use their non-dominant hand for two weeks. So, if they're right-handed, they're told to use their left hand "for pretty much anything that's safe to do," he says. "Using the mouse, stirring your coffee, opening doors. This requires people to practice self-control because their habitual tendency is to use their dominant hands." After two weeks, people who have practiced self-control control their aggression better. In one experiment, they're mildly insulted by another student and have the option of retaliating with a blast of white noise—but people who have practiced self-control respond less aggressively.

"I think, for me, the most interesting findings that have come out of this is that if you give aggressive people the opportunity to improve their self-control, they're less aggressive," Denson says. It's not that aggressive people don't want to control themselves; they just aren't very good at it. In fact, if you put aggressive people in a brain scanner and monitor their brain activity while insulting them, the parts of the brain involved in self-control are actually more active than in less aggressive people. So it might be possible to teach people who struggle with anger or violence problems to control themselves more easily.

For people who aren't inclined toward violence, it may also be useful to practice self-control—by trying to improve your posture, for example. In the short term, this can deplete self-control and make it harder to control your impulses. "But if you practice that over the long term, your self-control capacity gets stronger over time," Denson says. "It's just like practicing anything, really—it's hard at first." But, over time, it can make that annoying colleague easier to deal with.

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Healthy aging begins in the womb: Scientists investigate stress in pregnancy on brain aging

Professor Dr. Matthias Schwab examines a child. Credit: Szabo/UKJ

Ageing is a complex process involving physical, psychological, and environmental factors. Scientists believe that ageing can be programmed in the womb. One example of stress during pregnancy is the administration of glucocorticoids, i. e. synthetic stress hormones to accelerate fetal lung maturation in premature labor to allow breathing after birth. Could exposure to these stress hormones have an effect on health later in life?

„We know from previous studies that children whose mothers received glucocorticoids during pregnancy are less stress tolerant and have more concentration problems than their peers," reported Professor Matthias Schwab, the Neurologist heading the project. „Stress signal regulation is permanently disturbed and appears to lead to early ageing, in particular, of the brain", he added.

The scientists examine several risk groups. One consists of 10-year-olds born at the University Hospital Jena whose mothers had treatment with glucocorticoids during pregnancy. Two other groups are being followed up by psychologists at the University of Leuven in Belgium and include two-year-olds and 25-year-olds whose mothers suffered from stress during pregnancy. „A unique group studied at the Academic Medical Centre, University of Amsterdam includes persons born in Holland during the Dutch „Hunger Winter", of 1944/45," reported Prof. Schwab.

Scientists involved in the project use state-of-the art neuropsychological, neurophysiological, and MRI methods to analyse and compare biological and real age of the brain. The biotechnology companies Life Length in Madrid and Biocrates in Innsbruck measure biological age in chromosomes and screen blood samples to determine metabolic blood markers of age. "Environmental factors such as exposure to stress hormones or malnutrition during pregnancy change the readout of genetic information permanently," reported Matthias Platzer, Head of Genome Analysis at the Leibniz Institute for Age Research in Jena. „These epigenetic processes significantly change stress sensitivity for the rest of life," explained Prof Schwab. „Increased stress sensitivity makes one vulnerable to age-related diseases such as stroke and depression," he added.

In experimental studies, researchers aim to determine the period during pregnancy in which the brain is particularly vulnerable to stress. An important aspect of the research also involves studying a group of primates kept in Texas for possible translation of the findings to human subjects.

Understanding the biology of healthy ageing is desperately needed due to the worldwide ageing population and the economic costs of treating age-related diseases. „Environmental influences during life in the womb are early determinants for life-long good health and may be a target for preventive measures against early-ageing and age-related diseases," explained Prof. Schwab.

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Aging, overweight people stay happy, says new study

Growing older and being overweight are not necessarily associated with a decrease in mental well-being, according to a cross-cultural study looking at quality of life and health status in the US and the UK.

The study, led by Warwick Medical School at the University of Warwick, analysed lifestyle and health patterns in more than 10,000 people in both countries and their links to participants' mental and physical quality of life and health status.

Quality of life was evaluated using a measure which takes in eight different factors including perception of general health, pain, social functioning and mental health.

The researchers found that people reported better mental quality of life as they age, despite a decrease in physical quality of life.

This is in line with previous research, for example by Professor Andrew Oswald, also at the University of Warwick, which suggests that happiness levels follow a U-shape curve with their lowest point in the mid-40s after which they rise as people move into older age.

Supportive results were found in this cross-cultural comparison study in the UK and US – two countries which have different welfare and health-care systems, factors which could impact on people's quality of life.

The researchers also found that being overweight or obese did not have a significant impact on mental well-being levels, with people with a BMI of more than 30 showing similar mental quality of life levels to those considered to be a healthy weight.

For women in the US, low levels of physical exercise did not appear to impact on their mental well-being. This was not the case for men, where limited physical exercise had a significant adverse impact on their mental quality of life.

Dr Saverio Stranges, who led the study at Warwick Medical School at the University of Warwick, along with Dr Kandala Ngianga-Bakwin, said: "It's obvious that people's physical quality of life deteriorates as they age, but what is interesting is that their mental well-being doesn't also deteriorate – in fact it increases."

"We suggest that this could be due to better coping abilities, an interpretation supported by previous research showing older people tend to have internal mechanisms to deal better with hardship or negative circumstances than those who are younger.

"It could also be due to a lowering of expectations from life, with older people less likely to put pressure on themselves in the personal and professional spheres.

"With regard to our findings on excess body weight and its lack of significant impact on mental-wellbeing - this has been reported in previous research, i.e. the so-called "jolly fat" hypothesis, although not consistently."

The study also looked at the effect of sleep on quality of life, and found there was an optimum window of sleep duration.

Those who sleep between six and eight hours per day tended to have both better physical and mental health scores than those who slept on average less than six hours or more than eight hours.

Owing to its cross-cultural nature, the study was also able to identify differences between the quality of life of US and UK respondents.

In the US, respondents' social background was more likely to affect their quality of life, with those in higher socio-economic groups reporting better mental and physical quality of life.

The researchers suggested this could be due to the presence of universal healthcare in the UK, which has a levelling effect on well-being.

Also, levels of reported physical quality of life tended to be higher in the UK population while mental quality of life was higher in the US group - but researchers suggested this could be due to the slightly younger average age of the UK group and other intrinsic differences in the groups surveyed..

The study, Cross-cultural Comparison of Correlates of Quality of Life and Health Status:

The Whitehall II Study (UK) and the Western New York Health Study (US), was published in the European Journal of Epidemiology.

More information: DOI:10.1007/s10654-012-9664-z

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Discovery of brain's natural resistance to drugs may offer clues to treating addition

The left image shows GABA inhibitory neurons (labeled green) in the brain's reward pathway. The right panel shows electrical activity of GABA inhibitory neuron in a saline-injected or methamphetamine (METH)-injected mouse. Activation of the GABA type B receptor normally silences electrical activity, but has no effect in a mouse 24 hours after a single injection of methamphetamine Credit: Courtesy of Kelly Tan and Claire Padgett, Salk Institute for Biological Studies

A single injection of cocaine or methamphetamine in mice caused their brains to put the brakes on neurons that generate sensations of pleasure, and these cellular changes lasted for at least a week, according to research by scientists at the Salk Institute for Biological Studies.

Their findings, reported March 7 in Neuron, suggest this powerful reaction to the drug assault may be a protective, anti-addiction response. The scientists theorize that it might be possible to mimic this response to treat addiction to these drugs and perhaps others, although more experiments are required to explore this possibility.

"It was stunning to discover that one exposure to these drugs could promote such a strong response that lasts well after the drug has left the body," says Paul Slesinger, an associate professor in the Clayton Foundation Laboratories for Peptide Biology. "We believe this could be the brain's immediate response to counteract the stimulation of these drugs."

Scientists are trying to better understand the brain's response to psychoactive drugs in hopes of finding new ways to prevent and treat addiction. This research has become especially important as the number of deaths due to drug abuse now exceeds those due to car accidents, with more than 37,000 people dying from drugs in 2009, according to the Centers for Disease Control and Prevention. Slesinger and Christian Lüscher, a long-time collaborator at the University of Geneva, have been investigating the cellular changes in the brain that occur with drug abuse.

Dopamine is a primary neurotransmitter used in the brain's reward pathway -- generally speaking, the activity of dopamine neurons in the reward pathway increases in response to rewards, such as sex, food and drugs. Psychostimulants, such as methamphetamine and cocaine, co-opt this pathway and alter the brain's response to dopamine. Understanding the neuroadaptations that occur in the reward pathway in response to drugs of abuse may lead to the development of a treatment for drug addiction.

Previous research has shown that use of cocaine and methamphetamine in mice enhances excitatory connections to dopamine neurons. While most research has focused on these excitatory neurons, Slesinger and his colleagues looked at neurons that inhibit dopamine transmission, and found that one injection of cocaine or methamphetamine produces a profound change in the function of these inhibitory GABA neurons. These neurons were not able to control how they fired, so they would release more than the usual amount of inhibitory neurotransmitter.

"This persistent change in the inhibitory neurons occurs simultaneously with enhancement of excitatory inputs, indicating a possible compensatory mechanism that could be protective during exposure to drugs," Slesinger says.

The Salk researchers identified a change in the biochemical pathway in inhibitory GABA neurons that led to this protective effect. It involved a change in the activity of a protein, known as a phosphatase, which controls the levels of a receptor known to be important for controlling the electrical activity of the GABA neuron.

"This particular pathway -- involving a GABA type B receptor and a particular type of potassium channel -- was affected by psychostimulants in these inhibitory neurons," Slesinger says. "We noticed a dramatic reduction in the strength of this signaling pathway, which we showed was due to a decrease in the activity of the GABAB receptor and the potassium channel on the neuron's membrane surface."

"If we could tap into this pathway -- enhance the ability of inhibitory neurons to control the activity of dopamine neurons -- we might be able to treat some types of drug addiction," Slesinger says.

What is not known is how long the drug response lasts -- this study only looked at the brains of mice at two time points, 24 hours and seven days, after drug use -- and why addiction ultimately develops with chronic drug use. These are questions Slesinger and his colleagues are now investigating.

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Never Borrow From The Future

 

This is the most beautiful advice I have ever received in an email ...... Please don't close or delete this one before reading!   An Angel says, 'Never borrow from the future. If you worry about what may happen tomorrow and it doesn't happen, you have worried in vain. Even if it does happen, you have to worry twice.'   1. Go to bed on time. 2 Get up on time so you can start the day unrushed. 3. Say No to projects that won't fit into your time schedule, or that will compromise your mental health.    4. Delegate tasks to capable others. 5. Simplify and unclutter your life. 6. Less is more. (Although one is often not enough, two are often too many.) 7. Allow extra time to do things and to get to places.        8. Pace yourself. Spread out big changes and difficult projects over time; don't lump the hard things all together. 9. Take one day at a time. 10. Separate worries from concerns . If a situation is a concern, let go of the anxiety . If you can't do anything about a situation, forget it. 11. Live within your budget; don't use credit cards for ordinary purchases.    12.. Have backups; an extra car key in your wallet, an extra house key buried in the garden, extra stamps, etc. 13. K.M.S. (Keep Mouth Shut). This single piece of advice can prevent an enormous amount of trouble. 14. Do something for the Kid in You everyday.    15. Carry a book with you to read while waiting in line. 16. Get enough rest. 17. Eat right. 18. Get organized so everything has its place.    19. Listen to a tape while driving that can help improve your quality of life.   20. Write down thoughts and inspirations. 21. Every day, find time to be alone. 22. Having problems? Talk to someone. Try to nip small problems in the bud. Don't wait until it's time to go to bed. 23. Make friends.     24. Laugh. 25. Laugh some more! 26 Take your work seriously, but not yourself at all. 27. Develop a forgiving attitude (most people are doing the best they can).       28. Be kind to unkind people (they probably need it the most). 29. Sit on your ego. 30 Talk less; listen more. 31. Slow down. 32. Remind yourself that you are not the general manager of the universe. 33. Every night before bed, think of one thing you're grateful for that you've never been grateful for before. IT MAY HAVE A WAY OF TURNING THINGS AROUND FOR YOU. My instructions were to send this to four people that I care for and I picked you. I decided to send it to more than four, because I have more than four people that I care for. SEND IT FORWARD PLEASE, Not backward!

New way to image bleeding in arteries of the brain

New research from the University of Calgary's Hotchkiss Brain Institute shows that by using a CT scan (computerized tomography), doctors can predict which patients are at risk of continued bleeding in the brain after a stroke. This vital information will allow doctors to utilize the most powerful blood clotting medications for those with the highest risk.

One in three individuals will continue to accumulate blood in the brain from a leak in a small artery. Pooling blood in the brain has serious consequences, and could lead to disability or even death. Previously, doctors in emergency stroke situations could not discern whether or not a patient's brain bleeding had stopped. Using CT scan images, researchers can now identify "spot signs" that are seen as a small area of contrast on the CT scan. This spot sign is the actual location of bleeding within an artery in the brain.

"Technology that has emerged has allowed us to see the brain's blood flow system in exquisite detail to precisely identify the source of the problem," explains Dr. Andrew Demchuk, Professor in the departments of clinical neurosciences and radiology, and lead author of this study. "We are now at a point where we can harness this technology to develop better treatments for patients with a blockage or breakage in a brain artery. Ultimately this research will confirm when immediate treatment is necessary – essentially, as soon as you see the spot sign."

This research provides validation of a new imaging marker to identify patients that may need to be treated with clotting medications versus those that don't. "We must be very careful when and to whom these drugs are administered because they are so powerful at forming clots. These drugs can cause clots not only where there are holes and leaks – but also in intact arteries –potentially causing stroke and heart attacks," says Demchuk. "Therefore this CT scan selection is critical for targeting only those patients at highest risk of continued bleeding."

Clinical trials have now begun to test powerful clotting drugs in these patients.

This University of Calgary-led "PREDICT" study was coordinated with researchers at the Universities of Ottawa and Toronto, along with collaboration amongst nine other centres around the world. Their results were published in the March 8th online edition of the prestigious journal Lancet Neurology.

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Cannabinoid 2 receptors regulate impulsive behavior

Impulsivity is a personality trait characterized by behavioral actions that lack forethought or in which the subsequent consequences are not considered.
Credit: European Parliament

A new study lead by the Neuroscience Institute of Alicante reveals how manipulating the endocannabinoid system can modulate high levels of impulsivity. This is the main problem in psychiatric illnesses such a schizophrenia, bipolar disorder and substance abuse.

Spanish researchers have for the first time proved that the CB2 receptor, which has modulating functions in the nervous system, is involved in regulating impulsive behaviour.

"Such a result proves the relevance that manipulation of the endocannabinoid system can have in modulating high levels of impulsivity present in a wide range of psychiatric and neurological illness," explains SINC Jorge Manzanares Robles, a scientist at the Alicante Neuroscience Institute and director of the study.

Carried out on mice, the study suggests the possibility of undertaking future clinical trials using drugs that selectively act on the CB2 and thus avoid the psychoactive effects deriving from receptor CB1 manipulation, whose role in impulsivity has already been proven.

However, the authors of the study published in the British Journal of Pharmacology remain cautious. Francisco Navarrete, lead author of the study, states that "it is still very early to be able to put forward a reliable therapeutic tool."

The study assessed the actions of two cannabinoid drugs that stimulate and block CB2 in the mouse strain showing high levels of impulsivity. The scientists then analysed whether these drugs were capable of modulating impulsive behaviour and the cerebral modifications associated with this change in behaviour.

The authors concluded that CB2 receptor activity modulation reduced impulsive behaviour in mice, depending on the patterns that governed the administration of each drug. Furthermore, the genetic expression levels of CB2 tended to return to normal, leaning towards strains that had little impulsivity.

The Endocannabinoid System

The Endocannabinoid System mainly comprises two receptors (CB1 and CB2), two endogenous ligands and two metabolism enzymes. It regulates many aspects of embryonic development and is involved in many homeostatic mechanisms.

Although it was thought that CB2 only regulates immune response on a peripheral level, a study published in the Science journal in 2005 showed that it was found in the brain under normal conditions. Since then many authors have linked it to the regulation of emotional behaviour and cognitive functions.

For example, the same group of Spanish researchers has contributed greatly in applying this receptor in regulating anxiety and depression. Furthermore, others studies have demonstrated how their altered role is linked to increased chances of becoming depressed or anxious or taking drugs.

Virtue or defect?

Impulsivity is a personality trait characterised by behavioural actions that lack forethought or in which the subsequent consequences are not considered. The authors outline that this is "a normal behaviour that allows us as human beings to adapt to our surroundings under certain circumstances that require an immediate reaction."

Nonetheless, such behaviour can cause a disproportionate response and lead to a pathological state. There a multitude of psychiatric illness that are characterised by a high level of impulsivity. One of these includes substance abuse, which is extremely problematic for society in general.

More information: Francisco Navarrete, José M,.Pérez-Ortiz y Jorge Manzanares. "Regulación de la conducta de tipo impulsivo mediada por el receptor cannabinoide CB2 en ratones DBA/2". British Journal of Pharmacology 165:260-273, Jan 2012.

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