Search This Blog

Monday, January 30, 2012

White roofs cool buildings



THE UNIVERSITY OF MELBOURNE   

pamspix-White_Roof-iStock
The research aims to identify the most energy-efficient roof material.
Image: pamspix/iStockphoto
New research launched by the University of Melbourne and the City of Melbourne will give buildings owners across Melbourne access to information that can help their buildings absorb less heat and stay cooler during hot days. 
 
The research assesses the benefits of white roofs and aims to help residential, commercial and industrial building owners determine if white roofs are suitable for their buildings and guide them through the best materials to use. 

Lord Mayor Robert Doyle said Council had already put the research into practice by trialling a white roof on its ArtPlay building. 

“There has been a lot of talk about the energy consumption benefits of white roofs and we commissioned the University of Melbourne to undertake this research so we could get a local perspective on how white roofs can work in our city,” the Lord Mayor said. 

Councillor Cathy Oke, Chair of the Future Melbourne (Eco-City) Committee said commercial buildings in the City of Melbourne would benefit most from this tool. 

“White roofs can cool commercial buildings by 3% on hot days, which helps reduce the urban heat island effect and improve the health of city users,” Cr Oke said. 

Dr Dominique Hes, a senior lecturer at the University of Melbourne in sustainable architecture and lead author of the research explained that when painted white, roofs are able to reflect heat away from the building rather than absorbing it. 

“Reflective white paint on commercial building roofs reduces the energy used to cool the building. Melbourne’s CBD has over 3,500,000m2 of lettable commercial space. If the roofs of these buildings were painted white, the city could in theory reduce its CO2 emissions by 4.5 million MJ per year, 1.5 million kilos of CO2 or 3 million black balloons,” Dr Hes said. 

“White roofs are a low cost solution in making buildings more sustainable, particularly for our older buildings. And if our air conditioners are not working as hard, there are financial benefits for buildings owners as well.” 

The research monitored the temperatures of five test buildings at the University of Melbourne’s Burnley Campus for their performance with and without white coatings. The buildings with white roofs experienced significantly cooler temperatures, both on the exterior and interior.
Editor's Note: Original news release can be found here.

Mapping the Psychedelic Brain



by Greg Miller 
 
sn-psilocybin.jpg
 
Feeling disconnected? Psilocybin causes reduced blood flow (blue areas) in several of the brain's communication hubs.
Credit: R. L. Carhart-Harris et al., PNAS Early Edition (2012)
 
Drugs like psilocybin, the active ingredient in hallucinogenic mushrooms, play all sorts of tricks on the mind. They distort the perception of time, space, and self, and even untether the senses. Some researchers thought these strange effects might result from the drugs overexciting the brain. But the first study to use functional magnetic resonance imaging (fMRI) to examine brain activity in people who've taken psilocybin finds that the drug reduces neural firing in key communication hubs, essentially disconnecting some brain regions from each other.
In Central America and elsewhere, hallucinogenic drugs have been used for centuries in healing and religious ceremonies. Recent years have seen renewed interest in exploiting them to explore the neural basis of spirituality
 
 and potentially to treat depression, anxiety, and other mental illnesses. Yet neuroscientists know little about how these compounds act on the brain to cause such intensely altered experiences. Hallucinogenic drugs are tightly regulated, and few previous studies have tried to gauge their effects on the human brain. One study, using positron emission tomography (PET), found that psilocybin increases brain metabolism, especially in the frontal cortex.
In the new work, published this week in the Proceedings of the National Academy of Sciences, researchers led by psychopharmacologists Robin Carhart-Harris and David Nutt of Imperial College London used a different method, fMRI, to scan the brains of 30 people who were under the influence of psilocybin. The tight confines and loud noises of the scanner could be scary for someone on psilocybin, Nutt says. To minimize the chances of anyone having a bad trip, the researchers recruited people who'd taken hallucinogens previously, and they delivered the drug intravenously so that it would have a faster—and shorter—effect than, say, eating magic mushrooms.
The researchers performed two different types of MRI scans, one that measured blood flow throughout the brain and one that determined blood oxygenation, which neuroscientists generally assume is an indicator of neural activity. Contrary to the previous study, the scans showed thatpsilocybin reduces blood flow and neural activity in several brain regions
 
, including the posterior cingulate cortex and medial prefrontal cortex. The researchers quizzed the volunteers after the psilocybin had worn off and found that people in which these regions were most inhibited tended to report the most intense hallucinatory experiences. Nutt says he's not sure why the findings differ from those of the PET study, but he speculates that it could be due to the different time courses of the injectable drug his team used and the oral tablets used in the other research.
The posterior cingulate and medial prefrontal cortices are hubs in the so-called default mode network, a web of interconnected brain regions that becomes active when people allow their minds to wander. Some researchers have proposed that the default mode network is crucial for introspective thought and even for generating the sense of consciousness, and Nutt thinks the finding that psilocybin inhibits this network could help explain the surreal experiences the drug causes. "What I think is going on is that this network in the brain that pulls together a sense of self becomes less active," he says, "and you get this fragmented or dissipated sense of being."
"It's a very interesting study that raises lots of new questions," says Roland Griffiths, a psychopharmacologist at Johns Hopkins University in Baltimore, Maryland. He says the possibility that the drugs work by interfering with the default mode network is an appealing hypothesis that deserves further investigation.
Nutt and Griffiths are interested in the therapeutic potential of hallucinogenic drugs. Griffiths is involved in a pilot study testing whether psilocybin and psychotherapy can ease end-of-life anxiety in cancer patients. Nutt's group is looking into using the drug to treat depression, and this week in TheBritish Journal of Psychiatry, he and colleagues report that psilocybin can increase neural activity in brain regions related to memory
 
 when people recall events from their past. The drug also improved people's ability to access personal memories and related emotions, which the researchers say could be helpful during psychotherapy.
 

Posted by
Robert Karl Stonjek

Stop Embarrassing Me



 


Radha and Krishna“It is a natural psychology in every individual case that a person likes to hear and enjoy his personal glories enumerated by others. That is a natural instinct, and the Lord, being also an individual personality like others, is not an exception to this psychology because psychological characteristics visible in the individual souls are but reflections of the same psychology in the Absolute Lord.” (Shrila Prabhupada, Shrimad Bhagavatam, 1.6.33 Purport)
When someone tells you that they don’t like to be praised, know that it’s not the truth. Surely there is embarrassment over hearing someone else extol your virtues, telling you how much you mean to them and just how capable you are in a particular area, but this doesn’t mean that you dislike the praise. Would you rather have it the other way around, where others mock and make fun of your most valuable assets? The inclination towards deriving pleasure from accepting praise extends from the qualities of the Supreme Personality of Godhead. As we are but parts and parcels of His grand effulgence, His immeasurable storehouse of spiritual energy, we inherit some of His tendencies. As much as it exists in us, that tendency towards feeling pleasure from praise exists in full in the Personality of Godhead, a fact which subtly reveals the secret to finding lasting felicity.
Lord KrishnaWhy the secret? Why shouldn’t the one engagement that gives us the most happiness be known to everyone? The nature of the operating playing field is such that ignorance helps to enhance the experience. Just as when we watch a movie or television program we don’t like to think of it as a scripted production, if we knew the real purpose behind the material creation, the initial desire for fleeting enjoyment would be gone. In a movie, we know that the actors are just acting and that the story is scripted, but we willingly forget these facts during the time of the performance. Only through this method can we get into the story and have an emotional response from the experience.
The purpose of the creation at large is to pursue false enjoyment. The enjoyment is considered false because it is short-lived and based on ignorance. A dog is happy to get a few morsels of food from a dumpster, but a human being would consider the same fare to be repugnant. The only difference in the two cases is the level of intelligence. Ignorance is bliss in a situation where the better taste remains unknown. In the larger picture, if we were to know the real path to follow, then starting from the time of birth we would find life to be uncomfortable, with the predicament similar to being stuck in a prison.
Through uncovering the true meaning of life, however, we can more confidently accept the ultimate conclusion, that we are part and parcel of God meant to act in His service at all times. We can take the circuitous route to this end by studying so many different aspects of nature, including both matter and spirit, the influence of time and space, the infinite natures of both of these amazing aspects of creation, and the equality shared between all life forms. On the other hand, we could take the direct route, connecting with the fountainhead of both matter and spirit right away and deriving the necessary knowledge from there.
The latter option is preferable because it is more practical. It is difficult to accept so many different pieces of information and know what to do with them. Moreover, along the more deliberate path there are more opportunities for distraction, with the wayward spirit soul considering other engagements to be more delightful, more worthy of time. Should even all of the relevant information be processed and accepted, there is no guarantee that the proper engagement will be taken up. I may know all there is to know about math and science, but unless I apply the principles to find a better condition, the knowledge is really of no value.
When following the proper engagement from the beginning, despite a lack of knowledge of the component concepts, whatever knowledge and renunciation are required to continue that service will eventually arrive automatically. Therefore the Vedic seers recommend only one method of salvation for the sincere spiritualists of the modern age. That method is the constant chanting
 
 of the holy names, “Hare Krishna Hare Krishna, Krishna Krishna, Hare Hare, Hare Rama Hare Rama, Rama Rama, Hare Hare
 
”. Recite this mantra with firm faith and attention and make it your life’s occupation.
japa beadsWhy is this mantra and its recitation recommended over other methods such as the study of the Vedas, strict austerity measures, attending sacrifices, travelling to pilgrimage destinations, and following the principles of piety? The Hare Krishna mantra is a plea to be allowed to engage in the Lord’s service. The energy of the Lord known as Hara is also addressed. As she acts according to her constitutional position at all times, she is the best role model one could ask for. Requesting the energy to show us the way, to give us the strength to love God purely, without any motive for fruitive gain, the alleviation of distress, the advancement in knowledge, or the answers to life’s most difficult questions, represents the best prayer.
The name of Krishna is all-inclusive, for it directly addresses the Supreme Personality of Godhead, who is all-attractive. Chanting the name of Krishna through the maha-mantra praises the Lord at the same time, something which He loves. From this praise the living entity finds an easy way to take up service. If someone were to tell you to love God and to dedicate your life to serving Him, how would you go about doing that?
“If, however, you are unable to work in this consciousness, then try to act giving up all results of your work and try to be self-situated.” (Lord Krishna, Bhagavad-gita
 
, 12.11)
A possible solution might be to serve man through giving up the fruits of your work. “I will help the poor. I will help those who are less fortunate. The poor are God’s children after all, so the Lord will certainly be pleased by this effort.” Indeed, Lord Krishna
 
 does recommend the renunciation of the results of work in the famous discourse He gave to a hesitant warrior on a battlefield five thousand years ago. It should be remembered, however, that the giving up of the fruits of work option wasn’t the first one recommended by Krishna. Rather, it was the last option, when one couldn’t work directly for Krishna, follow the principles of bhakti-yoga, or always think of the Lord.
This means that the best way to serve Krishna is to directly engage in thinking of Him. It’s easier to think about someone if they have extraordinary qualities, features that are of importance to us. The celebrities earn their fame through their features, for if they were ordinary why would we care about them? From the attention paid to famous movie stars, athletes and politicians, we see that man already has the tendency to praise others and derive pleasure from that offering.
With the Supreme Lord, the ideal target of that praise is met. Shri Krishna is the most attractive, which means that every one of His personal aspects is worth contemplating. Krishna is the most beautiful. He has a blackish complexion and wears a peacock feather in His hair. His youthful visage is so amazing that it defeats the pride of thousands of cupids. Krishna is also the wealthiest and the strongest. Power brings attention, and Shri Krishna is the most powerful, so He garners the most attention from everyone.
Lord KrishnaThe Lord is also the most knowledgeable, for His doctrine of spirituality helps every single person, regardless of their position in life and their level of intelligence. The same can’t be said of any other doctrine. Renunciation applies only to those who are too attached to the senses. It doesn’t help those who are already renounced and looking for supreme pleasure. The acquisition of knowledge can apply to those who have a high capacity for intelligence, but what if someone isn’t inclined towards philosophy and rational thought? Should they be shut out from God’ service?
Chanting the holy names, which is the best way to praise Krishna, is available to every person, across all age groups. Through chanting the mind stays connected with Krishna, which is the number one recommendation for attaining salvation. Krishna may get embarrassed by hearing such praise, but this doesn’t mean that He doesn’t enjoy it. The more the loving emotions rise to the forefront of consciousness, the more one becomes firmly convinced of the benefits of bhakti-yoga, or devotional service
 
, whose cornerstone practice is the chanting of the holy names.
Based on the rules that Krishna has Himself laid down, the bhakta who wants to continually praise the Lord is given the opportunity to do so. If we want to spend every day engaged in describing the glories of Krishna and His associates, the divine forces will act to create endless opportunities. The same can’t be said of any other endeavor, for in fruitive activity we are competing with our fellow man for supremacy in a particular field. As each person has a right to manipulate the material elements to their liking, no one can be successful eternally, nor can they completely fend off the competing forces.
Lord KrishnaIn bhakti, even the competitive attitude turns out to be beneficial for all the parties involved. If I spend my time praising Krishna, addressing Him with the choicest verses, uttama-shlokas, others may see the behavior and want to imitate it. As Krishna’s glories are inexhaustible, the new competition entering the arena doesn’t do anything to dampen the spirits of the original glorifier. The more people in the field of bhakti the better, for Krishna’s glories continue to get told in new ways. With more glorifiers, there are more opportunities for others to hear about the sublime life that only comes from connecting with God.
If you already like to honor someone, why not honor the most honorable? He is willing to accept this praise at any time, and it’s such a fulfilling activity that you will never tire of it. In the rare occurrence that no one else is pleased by your effort, just knowing that Shri Krishna is happy will be enough to keep you going. Whether He gets embarrassed or not, Shyamasundara
 
 will never deny the outpouring of affection flowing His way.
In Closing:
Happy do you feel from words of praise,
Your ego to higher place it does raise.
Embarrassed by the words some will always say,
But are we not pleased if others compliments pay?
Through your words the highest person please,
Whose vision pain of suffering does ease.
Chant the holy names, for there is no cost,
In service to man there is guaranteed loss.
With bhakti your knowledge only to increase,
Spinning in wheel of suffering to finally cease.

Jeans and Kurtis..
















New mechanistic insights into adaptive learning



The brain is a fantastically complex and mysterious device, too large and with too many internal connections to be entirely programmable genetically. Its internal connectivity must therefore self-organize, based on the one hand on genetically regulated biases and on experience and learning on the other. The brain can change its internal connectivity based, for example, on correlations between the inputs it receives and the consequences of actions associated with those inputs, in a phenomenon we generally call associative learning. There are, in our daily life, numerous examples of this type of learning; its consequence is that a smell or a tune on the radio can trigger memories from the past, which lay dormant for some time.
“Such a recall — to a smell, sound, taste, or any other sensory stimulus — is evidence of associative learning, and what interested us here was to understand the tricks used by the brain to make these associations specific”, says Gilles Laurent, Director at the Max Planck Institute for Brain Research.
Together with his former Caltech student and postdoctoral fellow Stijn Cassenaer, Gilles Laurent set out to examine the phenomenon using insects as model system. A structure of great importance for learning in the insect brain is called the mushroom body. It is composed of a great many neurons (several hundreds of thousands in honeybees for example), and has been shown to be indispensable for several forms of olfactory learning (that is, learning associated to smells). What Cassenaer and Laurent set out to do was to explain an apparent paradox: how can a given odour be specifically memorised following an association with a reward, knowing that the brain signals representing reward are broadcast broadly into the mushroom body and therefore, not specific on their own.
They found that the answer relies on an interaction between the reward signal and a synaptic phenomenon known as spike-timing-dependent plasticity (STDP), itself discovered some 15 years ago by Henry Markram and Bert Sakmann, then at Max Planck Institute for Medical Research in Heidelberg. The new results indicate that STDP on its own — the strengthening or weakening of synaptic connections between neurons, that depends on the firing of those neurons in quick succession of one another — serves as a “tag” for the synapses that need modifying. Once so identified, the nonspecific reward signal can act specifically, and does so only at those precisely marked synapses. Laurent: “The discovery of this modulation is just the beginning. The molecular underpinning as well the process associated with the read out of the memories, are areas of much need-exploration”.
The study, "Conditional modulation of spike-timing-dependent plasticity for olfactory learning," was funded by the Lawrence Hanson Chair at Caltech, the National Institutes on Deafness and other Communication Disorders, Caltech's Broad Fellows Program, the US Office of Naval Research, and the Max Planck Society.
More information: Stijn Cassenaer & Gilles Laurent, Conditional modulation of spike-timing-dependent plasticity for olfactory learning. Nature, 25 January 2012, DOI:10.1038/nature10776
 


Provided by Max-Planck-Gesellschaft
"New mechanistic insights into adaptive learning." January 27th, 2012. http://medicalxpress.com/news/2012-01-mechanistic-insights.html
 

Posted by
Robert Karl Stonjek

Body location plays part in scratching pleasure




An itch is just an itch. Or is it? New research from Gil Yosipovitch, M.D., Ph.D., professor of dermatology at Wake Forest Baptist Medical Center and a world-renowned itch expert, shows that how good scratching an itch feels is related to the itch's location.
While previous studies by Yosipovitch have shown the pleasurability of itching, analysis of itch relief at different body sites and related pleasurability had not been performed until now. The study was published online this month by the British Journal of Dermatology.
"The goal of this study was to examine the role of the pleasurability of scratching in providing relief for itch," Yosipovitch explained. "We first evaluated whether itch intensity was perceived differently at three body sites, and then we investigated the potential correlation between the pleasurability and the itch relief induced by scratching."
Yosipovitch and colleagues induced itch on the ankles, forearms and backs of 18 study participants with cowhage spicules, which come from a type of legume found in tropical areas that are known to cause intense itching. The spicules were rubbed gently in a circular motion for 45 seconds within a small area of the skin and removed with adhesive tape once itch was induced. Itch intensity and scratching pleasurability were assessed every 30 seconds for a duration of five minutes using a Visual Analog Scale (VAS) to rate intensity – 0 for no itch, up to 10 for maximum unbearable itch.
Their results show that itch was perceived most intensely at the ankle and back, while the perception of itch and scratching relief were less pronounced on the forearm. Another major finding of the paper, as Yosipovitch explains, is that "the pleasurability of scratching the ankle appears to be longer lived compared to the other two sites."
Yosipovitch said this research helps lead to a better understanding of itch and how to relieve it for people who have skin disease.
"We see commonly involved areas such as the ankle and back in itchy patients with skin disorders caused by eczema or psoriasis," he said. "We never understood why those areas were more affected, and now we better understand that itch in these areas is more intense and pleasurable to scratch."
Yosipovitch said that while it is known that small nerve fibers are involved in unpleasant sensations such as itch and pain, he and other researchers now suspect that there are also specific nerve fibers involved in pleasure.
"If we could translate this to a treatment that induces a pleasurable relief sensation without damaging the skin, we may be able to help itchy patients," he said.
Provided by Wake Forest Baptist Medical Center
"Body location plays part in scratching pleasure." January 27th, 2012. http://medicalxpress.com/news/2012-01-body-pleasure.html
 

Posted by
Robert Karl Stonjek

Making memories last: Prion-like protein plays key role in storing long-term memories




Drosophila Orb2 plays an important role in the persistence of memory. Upon stimulation, Orb2 (shown in yellow) forms amyloid-like oligomers (shown in red), which are an essential ingredient for the formation of long-term memory. Credit: Illustration: Nicolle Rager Fuller, Sayo-Art
Memories in our brains are maintained by connections between neurons called "synapses". But how do these synapses stay strong and keep memories alive for decades? Neuroscientists at the Stowers Institute for Medical Research have discovered a major clue from a study in fruit flies: Hardy, self-copying clusters or oligomers of a synapse protein are an essential ingredient for the formation of long-term memory.
The finding supports a surprising new theory about memory, and may have a profound impact on explaining other oligomer-linked functions and diseases in the brain, including Alzheimer's disease and prion diseases.
"Self-sustaining populations of oligomers located at synapses may be the key to the long-term synaptic changes that underlie memory; in fact, our finding hints that oligomers play a wider role in the brain than has been thought," says Kausik Si, Ph.D., an associate investigator at the Stowers Institute, and senior author of the new study, which is published in the January 27, 2012 online issue of the journalCell.
Si's investigations in this area began nearly a decade ago during his doctoral research in the Columbia University laboratory of Nobel-winning neuroscientist Eric Kandel. He found that in the sea slug Aplysia californica, which has long been favored by neuroscientists for memory experiments because of its large, easily-studied neurons, a synapse-maintenance protein known as CPEB (Cytoplasmic Polyadenylation Element Binding protein) has an unexpected property.
A portion of the structure is self-complementary and—much like empty egg cartons—can easily stack up with other copies of itself. CPEB thus exists in neurons partly in the form of oligomers, which increase in number when neuronal synapses strengthen. These oligomers have a hardy resistance to ordinary solvents, and within neurons may be much more stable than single-copy "monomers" of CPEB. They also seem to actively sustain their population by serving as templates for the formation of new oligomers from free monomers in the vicinity.
CPEB-like proteins exist in all animals, and in brain cells they play a key role in maintaining the production of other synapse-strengthening proteins. Studies by Si and others in the past few years have hinted that CPEB's tendency to oligomerize is not merely incidental, but is indeed essential to its ability to stabilize longer-term memory. "What we've lacked till now are experiments showing this conclusively," Si says.
In the new study, Si and his colleagues examined a Drosophila fruit fly CPEB protein known as Orb2. Like its counterpart in Aplysia, it forms oligomers within neurons. "We found that these Orb2 oligomers become more numerous in neurons whose synapses are stimulated, and that this increase in oligomers happens near synapses," says lead author Amitabha Majumdar, Ph.D., a postdoctoral researcher in Si's lab.
The key was to show that the disruption of Orb2 oligomerization on its own impairs Orb2's function in stabilizing memory. Majumdar was able to do this by generating an Orb2 mutant that lacks the normal ability to oligomerize yet maintains a near-normal concentration in neurons. Fruit flies carrying this mutant form of Orb2 lost their ability to form long-term memories. "For the first 24 hours after a memory-forming stimulus, the memory was there, but by 48 hours it was gone, whereas in flies with normal Orb2 the memory persisted," Majumdar says.
Si and his team are now following up with experiments to determine for how long Orb2 oligomers are needed to keep a memory alive. "We suspect that they need to be continuously present, because they are self-sustaining in a way that Orb2 monomers are not," says Si.
The team's research also suggests some intriguing possibilities for other areas of neuroscience. This study revealed that Orb2 proteins in the Drosophila nervous system come in a rare, highly oligomerization-prone form (Orb2A) and a much more common, much less oligomerization-prone form (Orb2B). "The rare form seems to be the one that is regulated, and it seems to act like a seed for the initial oligomerization, which pulls in copies of the more abundant form," Si says. "This may turn out to be a basic pattern for functional oligomers."
The findings may help scientists understand disease-causing oligomers too. Alzheimer's, Parkinson's and Huntington's disease, as well as prion diseases such as Creutzfeldt-Jakob disease, all involve the spread in the brain of apparently toxic oligomers of various proteins. One such protein, strongly implicated in Alzheimer's disease, is amyloid beta; like Orb2 it comes in two forms, the highly oligomerizing amyloid-beta-42 and the relatively inert amyloid-beta-40. Si's work hints at the possibility that oligomer-linked diseases are relatively common in the brain because the brain evolved to be relatively hospitable to CPEB proteins and other functional oligomers, and thus has fewer mechanisms for keeping rogue oligomers under control.
Provided by Stowers Institute for Medical Research
"Making memories last: Prion-like protein plays key role in storing long-term memories." January 27th, 2012.http://medicalxpress.com/news/2012-01-memories-prion-like-protein-key-role.html
 
Posted by
Robert Karl Stonjek

CAMH discovery identifies potential target for anti-craving medications




Scientists at the Centre for Addiction and Mental Health (CAMH) have identified a potential target for the development of anti-craving medications for people with addictions to stimulants such as methamphetamine.
The discovery centres on a brain receptor related to the chemical dopamine, which has a complex role in addictive behaviours.
Using brain scans and a novel chemical probe developed in CAMH's Research Imaging Centre, CAMH scientists found that the probe had high levels of binding to the dopamine D3 receptor in some people with methamphetamine addiction, compared with those who had no addiction. Higher levels of D3 were also linked to participants' reported motivation to take drugs.
"This is the first time, to our knowledge, that anyone has shown that D3 receptor levels are high in people with an active addiction to methamphetamine," says Dr. Isabelle Boileau, a scientist in the Research Imaging Centre, part of the new Campbell Family Research Institute at CAMH. Boileau led the study that appears in the January 25, 2012 issue of The Journal of Neuroscience.
Using positron emission tomography (PET), Boileau's team looked at D3 levels in 16 people who were dependent on methamphetamine. Participants abstained from methamphetamine use for 14 days prior to brain scans. Their results were compared with scans from 16 participants with no addiction. On a separate day after scanning, participants were given a low dose of amphetamine, and they had to report how much they wanted to use drugs.
D3 receptors appear to have a role in craving, but it is not fully established how they are related to drug-related behaviours. The new chemical probe developed at CAMH, called 11C-(+)-PHNO, binds to dopamine D3 receptors. This probe allows researchers to study D3 in people for the first time, using PET scans, in order to answer questions about its role in stimulant addiction.
Understanding the role of brain receptors in addiction has enabled researchers to develop treatment medications, such as nicotine replacement therapy for smoking. So far, therapeutic strategies for stimulant addiction have focused on increasing activity with D2 receptors, where binding levels have been low.
"We can now suggest that any therapeutic approach aimed at increasing activity with D2 receptors should consider being selective at targeting D2, and not increasing D3 levels," says Boileau. "Our finding also supports the idea that D3 should be considered another target for anti-craving medications."
Boileau is also looking at the role of D3 in different types of addictions, including cocaine and gambling.
Building on CAMH's record of innovation and discovery, the Campbell Family Mental Health Research Institute will be accelerating discoveries in the areas of mood disorders, addictions, schizophrenia and cognitive impairment.
CAMH's Research Imaging Centre is the first of its kind in Canada where positron emission tomography (PET), magnetic resonance imaging (MRI), and imaging-genetics are dedicated to the study of mental illness and addictions.
This new discovery is an example of the innovative brain science at CAMH's new Research Imaging Centre, the first of its kind in Canada where positron emission tomography (PET), magnetic resonance imaging (MRI), and genetic imaging are dedicated to the study of mental illness and addictions.
Provided by Centre for Addiction and Mental Health
"CAMH discovery identifies potential target for anti-craving medications." January 25th, 2012. http://medicalxpress.com/news/2012-01-camh-discovery-potential-anti-craving-medications.html
 

Posted by
Robert Karl Stonjek

New deep brain stimulation device shows promising results




(Medical Xpress) -- A multi-site study of a new deep brain stimulation device for people with Parkinson’s disease has found the device to provide benefits to patients, potentially paving the way for unprecedented competition in the area of neurostimulation technology.
The study, whose co-authors included George Mandybur, MD, an associate professor of neurosurgery at the University of Cincinnati (UC) College of Medicine and Mayfield Clinic neurosurgeon, and Fredy Revilla, MD, an associate professor of neurology and UC Health neurologist, was published Jan. 11, 2012, in the online edition of Lancet Neurology. Mandybur and Revilla are members of the James J. and Joan A. Gardner Center for Parkinson’s Disease and Movement Disorders at the UC Neuroscience Institute, a specialty center within UC Health.
Principal investigator of the study was Michael Okun, MD, a neurologist and co-director of the Center for Movement Disorders and Neurorestoration at the University of Florida College of Medicine.
Deep brain stimulation (DBS) devices stimulate the subthalamic nucleus deep within the brain. Deep brain stimulation surgery has been shown to reduce symptoms of Parkinson’s and to improve quality of life.
The Lancet Neurology study examined the new Libra and LibraXP devices, which are manufactured by St. Jude Medical. The devices provide a constant, fixed-dose current, in contrast to the voltage-controlled device by Medtronic, Inc., which features a variable current and is the only DBS device on the market.
Participants in the randomized, controlled trial whose stimulators were turned on shortly after surgery experienced an increase of four hours of "on time” (with minimal symptoms), three months into the study. These benefits were significantly greater—2.5 more hours of "on time”—than those experienced by participants in the control group, whose stimulators were not turned on until the three-month mark.
Mandybur, who implanted the devices in 12 study participants at UC Health University Hospital, said the constant-current device compares favorably with the FDA-approved voltage-controlled device currently in use.
"This is the first study to look at constant-current effectiveness in Parkinson’s disease,” Mandybur says. "The new device appeared to be every bit as effective as the voltage-controlled device, but we won’t know for sure until there is a head-to-head comparison in future clinical trials. The devices are not identical.”
The St. Jude Neuromodulation Division, which funded the study, has applied for and is awaiting approval from the U.S. Food and Drug Administration for the Libra and LibraXP neurostimulators, which are currently available in Europe, Latin America and Australia.
The study results likely signal the imminent arrival of a competitor into a market currently filled only by Medtronic. "It will stir competition and it will light fires under people to develop new technology,” Mandybur says. "The same thing happened in the area of spinal cord stimulators.”
Revilla predicts that the new constant-current option will inspire Medtronic to create a constant-current option as well. "With further study,” he adds, "we may be able to establish clearly the differences and similarities of these two technologies.” 
Researchers theorize that constant-current stimulation might provide more accurate control of the spread of the electrical field than voltage-controlled stimulation. "But fundamental differences are unlikely,” writes Jens Volkmann, MD, of University Hospital of Würzburg, Germany, in an accompanying editorial in Lancet Neurology.
Parkinson’s disease, which afflicts more than 1 million Americans, is a degenerative neurological disorder involving the death of dopamine-producing nerve cells deep within the brain. There is no cure for Parkinson’s at this time, and scientists do not yet know how to halt its progression. Recent studies have shown that neurostimulation may slow the progression of the disease.
Candidates for deep brain stimulation are those who respond well to dopamine but over time have developed intolerable side-effects (mainly dyskinesias) and short duration of benefit.
 "When a person with Parkinson's develops wide motor fluctuations, requiring frequent doses of medications, along with intolerable side effects, it is time for DBS surgery,” Revilla says. "But it is still a requirement that the patient experience some benefit from the medications, even if it is short-lived.”
Revilla praised the 15 institutions whose close collaboration resulted in a study "that we expect will allow us to have alternative options for programming deep brain stimulation in patients who don’t respond well to conventional medical treatments.”
The Gardner Center team enrolled 12 patients, the second-highest number of any of the participating centers. (The highest enrollment was 13.)
Mandybur has received honoraria from Medtronic, Inc. Revilla is a consultant for Lundbeck, Inc.
Provided by University of Cincinnati
"New deep brain stimulation device shows promising results." January 25th, 2012. http://medicalxpress.com/news/2012-01-deep-brain-device-results.html
 

Posted by
Robert Karl Stonjek