In the Developing World, Solar Is Cheaper than Fossil Fuels

Peak power: A solar panel installed in Mwiki, Kenya.
Eight19

ENERGY

Advances are opening solar to the 1.3 billion people who don't have access to grid electricity.

• BY KEVIN BULLIS

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The falling cost of LED lighting, batteries, and solar panels, together with innovative business plans, are allowing millions of households in Africa and elsewhere to switch from crude kerosene lamps to cleaner and safer electric lighting. For many, this offers a means to charge their mobile phones, which are becoming ubiquitous in Africa, instead of having to rent a charger.

Technology advances are opening up a huge new market for solar power: the approximately 1.3 billion people around the world who don't have access to grid electricity. Even though they are typically very poor, these people have to pay far more for lighting than people in rich countries because they use inefficient kerosene lamps. While in most parts of the world solar power typically costs far more than electricity from conventional power plants—especially when including battery costs—for some people, solar power makes economic sense because it costs half as much as lighting with kerosene.  

Hundreds of companies are swooping in to grab a piece of this market.

"This sector has exploded," says Richenda Van Leeuwen, senior director for the Energy and Climate team at the United Nations Foundation. "There's been a sea change in the last five years."

The sudden interest is fueled by the advent of relatively low-cost LEDs, she says. Not long ago, powering lightbulbs required a solar panel that could generate 20 to 30 watts, since only incandescent lightbulbs were affordable. LEDs are far more efficient. Now people can have bright lighting using a panel that only generates a couple of watts of power, Van Leeuwen says.  

But such technological improvements aren't quite enough to open up the market. High-quality LED systems, with a pair of lamps and enough battery storage for several hours of lighting, cost less than $50. The systems can pay for themselves in less than two years, but the upfront cost is still too steep for many people. 

Eight19, a company based in Cambridge, U.K., is one of several companies offering some type of payment plan to make the systems affordable. Customers pay $10 for the solar lighting system, which includes a 2.5-watt solar panel, two LED overhead lamps, and a lithium-iron phosphate battery pack. Then they pay a weekly fee for the power it generates.

Winning numbers: Customers enter a numerical code to access power for lights and a mobile phone charger.
Eight19

Each week, users buy a scratch card for about $1 from a local vendor. It gives them a number that they text to Eight19 for verification. The company sends them a verification code that they enter into a keypad on the battery pack. The code electronically unlocks the device for a week, allowing the battery to supply power to the LEDs or to a phone charger.

Several other companies, including major telecoms, are trying variants on this pay-as-you-go approach. One thing that sets Eight19 apart is that after a customer has covered the cost of the device—typically in about 18 months—he or she can trade up for a bigger one with a larger solar panel, a bigger battery, and more lights, and the capacity to power a small radio. In this way, using only the money they would have been spending on kerosene or for renting phone chargers, they can gradually get to the point where they have enough power for, say, a refrigerator, or a money-making appliance such as a sewing machine, says Simon Bransfield-Garth, CEO of Eight19.

Eight19 has tested the system with several hundred customers, and it is starting a project to sell 4,000 systems in cooperation with the NGO Solar Aid, which will help with distribution.

But Eight19 is a relatively small player so far. More established companies such as D.light have sold over one million solar lighting systems. Bransfield-Garth sees a lot of room for growth. "The poorest people are paying disproportionately high prices for their needs," he says. "Solar power works well in this market." 

White roofs cool buildings

THE UNIVERSITY OF MELBOURNE

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 

 

 

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.

Source: Science
http://news.sciencemag.org/sciencenow/2012/01/mapping-the-psychedelic-brain.html?ref=em

 

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Robert Karl Stonjek

Stop Embarrassing Me

“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. Why 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. Why 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. The 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. In 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

 

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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

 

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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

 

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Robert Karl Stonjek