Stimulating the brain to improve speech, memory, numerical abilities

One of the most frustrating challenges for some stroke patients can be the inability to find and speak words even if they know what they want to say. Speech therapy is laborious and can take months. New research is seeking to cut that time significantly, with the help of non-invasive brain stimulation.

"Non-invasive brain stimulation can allow painless, inexpensive, and apparently safe method for cognitive improvement with with potential long term efficacy," says Roi Cohen Kadosh of the University of Oxford. Recent results, presented this week at a meeting of cognitive neuroscientists in Chicago, offer exciting possibilities for improving variety of abilities – from speech to memory to numerical proficiency.

A focus of many of these studies is tDCS – transcranial direct current stimulation. In tDCS, researchers apply weak electrical currents to the head via electrodes for a short period of time, for example 20 minutes. The currents pass through the skull and alter spontaneous neural activity. Some types of stimulation excite the neurons, while others suppress them. Subjects usually feel only a slight tingling for less than 30 seconds. The effects of tDCS can last for up to 12 months, Cohen Kadosh says, "most likely due to molecular and cellular changes that are important mechanisms implementing learning and memory."

Stimulating speech recovery

For Jenny Crinion of University College London, who is both a neuroscientist and clinical speech and language therapist, the interest in tDCS sprang from a desire to help stroke patients through their long recovery. While speech therapy works well at improving speech following aphasic stroke, it can be frustratingly slow. She hopes to pair brain-stimulation interventions with proven language-rehabilitation methods, Crinion says, "such that the same maximum recovery is ultimately achieved as with therapy alone but with fewer hours of rehab."

Crinion's current work focuses on understanding how tDCS affects the areas of the brain involved in speech production. She paired an fMRI picture-naming study with a 6-week-long tDCS and word-finding treatment study to see if brain stimulation could improve stroke patients' speech both immediately after treatment and three months later. In the picture-naming task, people were presented with pictures of simple, everyday words such as car and asked to name them as quickly and accurately as possible.

The results support other studies that tDCS can speed up word finding in both healthy older people and stroke patients, and are helping to identify which parts of the brain should be stimulated. "My work supports the idea that excitatory tDCS could be applied to the stroke hemisphere to optimize recovery," Crinion says. At the same time, she cautions, one type of treatment may not fit all patients, and further work will clarify whether some patients may also benefit from treatments targeted at the brain hemisphere not affected by stroke.

"What I've been most impressed by is how learning and, in the case of stroke patients, re-learning of language continues and the brain remains plastic, adapting and changing throughout our lifespan," Crinion says. "It is never too late to recover more and continue to improve with the right training."

Stimulating better memory

In a different set of experiments that look at the effects of brain stimulation on memory, Paulo Sérgio Boggio of Mackenzie Presbyterian University in São Paulo, Brazil, used tDCS to try to enhance the memory of Parkinson's and Alzheimer's disease patients. His work builds on research that showed that tDCS can enhance working memory in healthy subjects.

In his study of Alzheimer's patients, Boggio tested how many sessions of tDCS would lead to sustained improvements in memory and visual recognition. His team used five consecutive sessions of tDCS to excite two different areas of the brain involved in motor planning, organization, and regulation. Visual recognition increased by as much as 18% in the Alzheimer's patients, and the effects lasted a month. In a similar study with Parkinson's disease patients, tDCS improved memory by 20%.

"These studies demonstrate the potential of tDCS for memory improvement in elderly with Parkinson's or Alzheimer's disease and open a venue for future studies to examine the potential long-term effects," Boggio says. "It is important to understand that these tools are still on research level but at the same time are showing promising results with some advantages – low cost, simple to use, and reduced side-effects."

Stimulating numerical skills

Cohen Kadosh of the University of Oxford studied a very different application of tDCS – how to improve how people learn about numbers. Citing a recent study that found that approximately 20% of British adults have numeracy skills below the minimum requirement for being fully functional in the modern economy, Cohen Kadosh explains that there is currently no solution for low numerical abilities, aside from behavioral training. "I believe that this is an important problem with many implications for society," he says.

His studies have found that it is possible to enhance numerical abilities using tDCS applied to the part of the brain called the posterior parietal cortex. The observed improvements lasted up to 6 months after tDCS and were specific to the trained material.

Cohen Kadosh has also tested the effects of tDCS on people with low numerical abilities due to congenital factors – dyscalculia, the equivalent to dyslexia with numbers that affects about 5% of the population. For those individuals, tDCS was only effective if it targeted different regions of the brain than those in people without dyscalculia. "This suggests that people with dyscalculia recruit different brain areas for numerical processing, probably due to brain reorganization," he says.

Future studies are investigating the use of tDCS to improve mathematical learning in children with low numerical abilities. "Cumulatively, these experiments advance our understanding of how numerical abilities are sub-served in the typical and atypical brain, and provide a possible means to improve numerical cognition, thus having important implications for education, intervention, and rehabilitation."

The symposium "Using Non-Invasive Brain Stimulation to Enhance Cognitive and Motor Abilities in the Typical, Atypical, and Aging Brain" takes place on April 2, 2012, at the 19th annual meeting of the Cognitive Neuroscience Society (CNS). More than 1400 scientists are attending the meeting in Chicago, IL, from March 31 to April 3, 2012.

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Carrier of the Holy Name

“Surely this Ashoka grove, which is filled with many trees, must be guarded by many Rakshasas, as it is carefully tended to and purified in every possible way. And the guards there must protect the trees, and the all-pervading deity, the wind, does not blow there.” (Hanuman, Valmiki Ramayana, Sundara Kand, 13.62-63) dhruvam tu rakṣo bahulā bhaviṣyati vana ākulā | aśoka vanikā cintyā sarva saṃskāra saṃskṛtā || rakṣiṇaḥ ca atra vihitā nūnam rakṣanti pādapān | bhagavān api sarva ātmā na atikṣobham pravāyati || Whether or not he did it intentionally, Ravana kept Sita Devi in a sacred place, one unlike any other inside of Lanka. While the rest of the town was adorned with gold, jewels and crystals, Sita’s surroundings were pristine, thoroughly cultivated, sacred and well-guarded. The trees were so aligned and protected that not even the wind could blow there violently. That being the case, how could the wind’s son, ShriHanuman, enter that place and find the most beautiful woman in the world, who was waiting for news of her husband, to know whether or not He was going to come and rescue her and whether He was feeling the pain of separation from her? Despite the impediments and the restriction placed on the wind, Rama’s messenger, Ramadutta, would find a crafty way to enter not only the Ashoka garden, but also Sita’s heart. Imagine being stuck in a place where you have nothing to do except count the seconds until the inevitable end of everything. Worse than being held in a prison, Sita was constantly harassed, day after day, by people ordered to make her stay in this grove a living hell. What had she done to deserve this? Up until this time she was respected by everyone. A man takes his pride from his manhood - his ability to protect his dependents, to brave through tough times and to show strength when it is difficult. A woman gets her standing from her chastity - the fact that she doesn’t give out her love easily. Take away a man’s manhood and you take away his essence, and take away a woman’s chastity and her reputation is ruined. Sita was known as the most chaste woman in the world; therefore she automatically earned the highest respect. Moreover, her husband was famous as the manliest fighter, a person capable of defending any person who sought His protection. He has actually maintained this characteristic since the beginning of time and still does to this day. The mere utterance of His name delivers countless more individuals than does His personal self. In fact, Sita’s ability to remain alive while held against her will in Lanka shows the power of the holy name. How does this work exactly? The Supreme Lord is known by His attributes; otherwise He is not distinguished from any other person. Since the entire creation falls under His purview, into the definition of “God”, it is tempting to think that God is attributeless. “He must be without a form because only those things which are subordinate to material nature undergo change. If God creates nature, He must not ever change. Therefore His form must be nonexistent, i.e. He must be formless.” This is surely one way to look at God. Take every single activity, motion of nature, event in life, and just abstract out to the largest scale and you get “the creation”. Since this giant neural network of cause and effect is guided by intelligence, there must be someone pushing the buttons, someone who is the source of that intelligence. Without knowing this person’s features, the abstract understanding remains the height of realization. The Vedas refer to the abstract, all-pervading Absolute Truth as Brahman. Brahman is everything. He is the living entities as well, who are struggling hard with the material nature. Even matter is from Brahman, but it is a different kind of energy, an inferior one to be more precise. The living entities that are Brahman are superior. The wise take to studying the scriptures that detail the differences between the two energies and make themselves familiar with Brahman in the process. Yet, just as the light of the sun does not give us the complete picture of the sun itself, the entire creation as a whole, the light of Brahman, does not provide the necessary insight into the fountainhead of all energies, the Supreme Lord. While Brahman is impersonal, the Lord takes on personal traits, spiritual qualities belonging to forms known as avataras, to show us what Brahman actually looks like. Brahman is actually subordinate to Parabrahman, which is the title reserved specifically for God. The spiritual attributes of the formed incarnations show that Parabrahman is the most renounced, the wealthiest, the strongest, the wisest, the most famous and the most beautiful. In His avatara as Lord Rama, God graced a select few individuals with His sweet smile, His dedication to piety, and His promise of protection. In the Vedic system the husband’s duty is to protect the wife, who operates under his direction. Rama was perfect in this regard, as Sita always felt safe in His company. Even when Rama was sent away from His kingdom of Ayodhya, Sita did not find the pleasure of life in the palaces preferable to Rama’s company in the forest. She felt safer with her husband by her side. Therefore it was a little disconcerting when Sita was taken away by Ravana, the Rakshasa king of Lanka. Not that Rama failed to defend against Ravana, the ogre didn’t even mount an attack against Rama. Rather, he took Sita away in secret, while Rama temporarily wasn’t by her side. Through the divine will, the need for bringing about Ravana’s end, Rama purposefully limited His display of opulence. The holy name, however, is never limited. Sita kept reciting it while in Lanka, so she was able to think of her husband, keeping Him by her side even though He was far, far away. Ravana tried to win her over but to no avail. She was not budging from her dedication to chastity. She would not even look at the vile creature who already had hundreds of the most beautiful princesses as queens. The holy name thus proved many thousands of years ago during Sita’s time to be most powerful, and it is just as powerful today. Shri Hanuman even used it to succeed in his mission to find Sita. Lord Rama, being the most knowledgeable, could have located Sita Himself, but the wiser thing to do was to allow those eager to serve Him the chance to take up the cause. The living entities are mini-gods, so they have some independence in their exercise of freedom. Brahman is transcendental to matter; hence there is no reason to be subjected to the threefold miseries. The pains inflicted by natural forces, the influence of other living entities, and the workings of the body and mind have no bearing on the qualities of Brahman. Nevertheless, the conditioned living entities struggle very hard with material nature; a fact we’re reminded of by Lord Krishna in the Bhagavad-gita. “The living entities in this conditioned world are My eternal, fragmental parts. Due to conditioned life, they are struggling very hard with the six senses, which include the mind.”  (Lord Krishna, Bhagavad-gita, 15.7) Krishna is the same Rama but in a different outward, spiritual manifestation. Lord Krishna is considered the original Personality of Godhead, the origin of Parabrahman. His face is full of sweetness, as are His words. The living entities struggle with material nature, but when they find their occupational duty of bhakti-yoga, or devotional service, the same material elements become favorable. This was quite evident with Shri Hanuman, who found himself placed smack dab in the middle of a supremely difficult mission. While a band of monkeys took up the task of finding Sita, only Hanuman from that group made it to Lanka, for no one else could leap across the massive ocean separating the island from the mainland. How did Ravana bring Sita back there then? He had an aerial car that previously belonged to his brother Kuvera. Ravana used it to fly around and terrorize people. Hanuman had to find Sita all by himself, without anyone around to help. After overcoming many obstacles, including a doubtful mind fearing the worst outcome, Hanuman was on the precipice of finding King Janaka’s daughter, though he didn’t know it. In the above referenced verse from the Ramayana, Hanuman is thinking over what he will find in the Ashoka wood, the one place in Lanka he had yet to search. Having mentally entered the area, he started surveying the scene and going over what he should expect. The place would be sacred and guarded by Rakshasas. It would be so well-protected that the wind wouldn’t blow there. Thus Hanuman would have to contract his form, something he was more than capable of doing. He did not want to get noticed by the Rakshasas, because that might jeopardize the success of the mission. The fact that the wind wasn’t blowing there violently was another impediment to deal with. On the strength of the wind Hanuman was able to leap across the ocean and make it to Lanka. The wind, or air, is actually the vital force to sustain life within all of us. One who can learn to control the vital breaths within the body can find good health and the ability to survive through duress. Therefore it shouldn’t surprise us that the ancient yoga practice of pranayama is very popular today. Hanuman, however, didn’t require violent wind to find Sita. He was determined to please Rama, to keep the smile on the face of the jewel of the Raghu dynasty no matter what. Using his keen intelligence, he would find his way into the woods unnoticed. He would meet with Sita and give her news about Rama. Along with regular chanting of the holy names, “Hare Krishna Hare Krishna, Krishna Krishna, Hare Hare, Hare Rama Hare Rama, Rama Rama, Hare Hare”, hearing about God and His activities is the best medicine for the mind and the heart. In this respect, Hanuman gave tremendous transcendental healing satisfaction to Sita, who loved to hear about her husband and how He was doing. Hanuman would return later to Lanka, but this time with the full army of monkeys commanded by Sugriva. Rama and His younger brother Lakshmana would be there too, ready to rid the world of Ravana. Hanuman’s determination played a vital role in the eventual victory, and his presence continues to be felt today. Chanting the name of Rama brings with it the vision of Sita, Lakshmana and Hanuman. Rama may have personally defeated Ravana, but His name is what carried Hanuman into Lanka and helped him defeat the elements obstructing his path. Rama’s name helped Sita remain alive while in a perilous condition, and it continues to deliver the souls struggling with the pangs of Kali Yuga, the present age of quarrel and hypocrisy. Therefore the holy name and its many carriers are the only life raft for the souls looking for true enlightenment and lasting happiness. As Hanuman is one who cherishes the holy name and keeps it with him at all times, he is supremely worshipable. In Closing: Sita, in a tough situation she did find, Harassed by vile witches, troubled she was in mind. She did nothing wrong in life, her husband she missed, Repeating His holy name her only solace. Hanuman, Ashoka wood ready to enter, But first conditions in mind he did ponder. Trees to be guarded by Rakshasas full of sin, So aligned that to enter difficult for even the wind. Hanuman’s determination the Rakshasas to beat, In his heart, Sita, Rama and Lakshmana take their seat.

How stress influences disease: Research reveals inflammation as the culprit

Stress wreaks havoc on the mind and body. For example, psychological stress is associated with greater risk for depression, heart disease and infectious diseases. But, until now, it has not been clear exactly how stress influences disease and health.

A research team led by Carnegie Mellon University's Sheldon Cohen has found that chronic psychological stress is associated with the body losing its ability to regulate the inflammatory response. Published in the Proceedings of the National Academy of Sciences, the research shows for the first time that the effects of psychological stress on the body's ability to regulate inflammation can promote the development and progression of disease.

"Inflammation is partly regulated by the hormone cortisol and when cortisol is not allowed to serve this function, inflammation can get out of control," said Cohen, the Robert E. Doherty Professor of Psychology within CMU's Dietrich College of Humanities and Social Sciences.

Cohen argued that prolonged stress alters the effectiveness of cortisol to regulate the inflammatory response because it decreases tissue sensitivity to the hormone. Specifically, immune cells become insensitive to cortisol's regulatory effect. In turn, runaway inflammation is thought to promote the development and progression of many diseases.

Cohen, whose groundbreaking early work showed that people suffering from psychological stress are more susceptible to developing common colds, used the common cold as the model for testing his theory. With the common cold, symptoms are not caused by the virus — they are instead a "side effect" of the inflammatory response that is triggered as part of the body's effort to fight infection. The greater the body's inflammatory response to the virus, the greater is the likelihood of experiencing the symptoms of a cold.

In Cohen's first study, after completing an intensive stress interview, 276 healthy adults were exposed to a virus that causes the common cold and monitored in quarantine for five days for signs of infection and illness. Here, Cohen found that experiencing a prolonged stressful event was associated with the inability of immune cells to respond to hormonal signals that normally regulate inflammation. In turn, those with the inability to regulate the inflammatory response were more likely to develop colds when exposed to the virus.

In the second study, 79 healthy participants were assessed for their ability to regulate the inflammatory response and then exposed to a cold virus and monitored for the production of pro-inflammatory cytokines, the chemical messengers that trigger inflammation. He found that those who were less able to regulate the inflammatory response as assessed before being exposed to the virus produced more of these inflammation-inducing chemical messengers when they were infected.

"The immune system's ability to regulate inflammation predicts who will develop a cold, but more importantly it provides an explanation of how stress can promote disease," Cohen said. "When under stress, cells of the immune system are unable to respond to hormonal control, and consequently, produce levels of inflammation that promote disease. Because inflammation plays a role in many diseases such as cardiovascular, asthma and autoimmune disorders, this model suggests why stress impacts them as well."

He added, "Knowing this is important for identifying which diseases may be influenced by stress and for preventing disease in chronically stressed people."

More information: “Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk,” by Sheldon Cohen et al. PNAS, 2012.

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Researchers link neural variability to short-term memory and decision making

A team of University of Pittsburgh mathematicians is using computational models to better understand how the structure of neural variability relates to such functions as short-term memory and decision making. In a paper published online April 2 inProceedings of the National Academy of Sciences (PNAS), the Pitt team examines how fluctuations in brain activity can impact the dynamics of cognitive tasks.

Previous recordings of neural activity during simple cognitive tasks show a tremendous amount of trial-to-trial variability. For example, when a person was instructed to hold the same stimulus in working, or short-term, memory during two separate trials, the brain cells involved in the task showed very different activity during the two trials.

"A big challenge in neuroscience is translating variability expressed at the cellular and brain-circuit level with that in cognitive behaviors," said Brent Doiron, assistant professor of mathematics in Pitt's Kenneth P. Dietrich School of Arts and Sciences and the project's principal investigator. "It's a fact that short-term memory degrades over time. If you try to recall a stored memory, there likely will be errors, and these cognitive imperfections increase the longer that short-term memory is engaged."

Doiron explains that brain cells increase activity during short-term memory functions. But this activity randomly drifts over time as a result of stochastic (or chance) forces in the brain. This drifting is what Doiron's team is trying to better understand.

"As mathematicians, what we're really trying to do is relate the structure and dynamics of this stochastic variability of brain activity to the variability in cognitive performance," said Doiron. "Linking the variability at these two levels will give important clues about the neural mechanisms that support cognition."

Using a combination of statistical mechanics and nonlinear system theory, the Pitt team examined the responses of a model of a simplified memory network proposed to be operative in the prefrontal cortex. When sources of neural variability were distributed over the entire network, as opposed to only over subsections, the performance of the memory network was enhanced. This helped the Pitt team make the prediction published in PNAS, that brain wiring affects how neural networks contend with—and ultimately express—variability in memory and decision making.

Recently, experimental neurosciencists are getting a better understanding of how the brain is wired, and theories like those published in PNAS by Doiron's group give a context for their findings within a cognitive framework. The Doiron group plans to apply the general principle of linking brain circuitry to neural variability in a variety of sensory, motor, and memory/decision-making frameworks.

More information: For more information on Doiron's lab, visit http://www.math.pi … Welcome.html

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Death anxiety increases atheists' unconscious belief in God

New research suggests that when non-religious people think about their own death they become more consciously skeptical about religion, but unconsciously grow more receptive to religious belief.

The research, from the Department of Psychology at the University of Otago in New Zealand, also found that when religious people think about death, their religious beliefs appear to strengthen at both conscious and unconscious levels. The researchers believe the findings help explain why religion is such a durable feature of human society.

In three studies, which involved 265 university students in total, religious and non-religious participants were randomly assigned to "death priming" and control groups. Priming involved asking participants to write about their own death or, in the control condition, about watching TV.

In the first study, researchers found that death-primed religious participants consciously reported greater belief in religious entities than similar participants who had not been death-primed. Non-religious participants who had been primed showed the opposite effect: they reported greater disbelief than their fellow non-religious participants in the control condition.

Study co-author Associate Professor Jamin Halberstadt says these results fit with the theory that fear of death prompts people to defend their own worldview, regardless of whether it is a religious or non-religious one.

"However, when we studied people's unconscious beliefs in the two later experiments, a different picture emerged. While death-priming made religious participants more certain about the reality of religious entities, non-religious participants showed less confidence in their disbelief," Associate Professor Halberstadt says.

The techniques used to study unconscious beliefs include measuring the speed with which participants can affirm or deny the existence of God and other religious entities. After being primed by thoughts of death, religious participants were faster to press a button to affirm God's existence, but non-religious participants were slower to press a button denying God's existence.

"These findings may help solve part of the puzzle of why religion is such a persistent and pervasive feature of society. Fear of death is a near-universal human experience and religious beliefs are suspected to play an important psychological role in warding off this anxiety. As we now show, these beliefs operate at both a conscious and unconscious level, allowing even avowed atheists to unconsciously take advantage of them."

The paper co-authors also included Jonathan Jong, currently at the University of Oxford, who undertook the experiments as part of his PhD thesis, and Matthias Bluemke, currently at the University of Heidelberg. Associate Professor Halberstadt was Jong's supervisor.

The findings from the three experiments will be published in the Journal of Experimental Social Psychology.

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Molecular imaging links systemic inflammation with depression

New research published in the April issue of The Journal of Nuclear Medicine reveals that systemic inflammation causes an increase in depressive symptoms and metabolic changes in the parts of the brain responsible for mood and motivation. With this finding, researchers can begin to test potential treatments for depression for patients that experience symptoms that are related to inflammation in the body or within the brain.

Multiple studies in rodents have shown that inflammation in the body has effects on the brain. This has also been shown in a few human studies—both through measurements of behavioral changes and brain imaging—when subjects were engaged in various computer tasks. The study "Glucose Metabolism in the Insula and Cingulate Is Affected by Systemic Inflammation in Humans," however, for the first time measured brain activity when subjects were at rest.

"In the study we used F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET), which can accurately measure glucose metabolism in the brain, to determine which brain regions responded to systemic inflammation. Since the subjects were at rest, the changes we observed in the brain can only attributed to systemic inflammation," noted Jonas Hannestad, MD, PhD, lead author of the article.

In the study, nine healthy individuals received a double-blind endotoxin (which elicits systemic inflammation and mild depressive symptoms such as fatigue and reduced social interest) and placebo on different days. After administration, F-18 FDG PET was used to measure the differences in the cerebral metabolic rate of glucose in the insula, cingulate and amygdala regions of the brain. Behavior changes were also primarily assessed on the Montgomery-Asberg Depression Rating Scale (MADRS).

A statistical analysis of the results showed that endotoxin administration was associated with a higher normalized glucose metabolism (NMG) in the insula and lower NMG in the cingulate compared to the placebo; there was no significant difference in the NMG in the amygdala. Seven of nine subjects had an increase in NMG in the insula and a decrease in NMG in the cingulate, and all nine subjects had a decrease in NMG in the right anterior cingulate, suggesting that systemic inflammation induces fundamental physiologic changes in regional brain glucose metabolism. In addition, the MADRS increased for each subject after endotoxin administration, whereas no significant change was noted with the placebo.

Most researchers agree that depression is not a homogeneous disease, but rather that there are multiple mechanisms that can lead to similar symptoms. "If we can show that a subtype of depression is caused in part by inflammation," said Hannestad, "we can test the ability of treatments that reduce inflammation in only patients in whom we believe inflammation plays a role. In the future, I expect that researchers in this field will be able to develop more precise PET measures that can be used to distinguish between, for instance, a person with 'inflammatory depression' and a person with another kind of depression. PET could then be used as diagnostic biomarker to separate subtypes of depression and as a therapeutic biomarker to detect the response to treatment."

Nearly 17 percent of adults experience depression at some point over their lifetime, with 30.4 percent of cases classified as severe, according to the U.S. National Institute of Mental Health. Fifty-seven percent of adults with depression report receiving treatment in the past 12 months, although 37.8 percent receive minimally adequate treatment.

More information: "Glucose Metabolism in the Insula and Cingulate Is Affected by Systemic Inflammation in Humans" Journal of Nuclear Medicine.

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Scientists shed light on age-related memory loss and possible treatments

Scientists from the Florida campus of The Scripps Research Institute have shown in animal models that the loss of memory that comes with aging is not necessarily a permanent thing.

In a new study published this week in an advance, online edition of the journal Proceedings of the National Academy of Sciences, Ron Davis, chair of the Department of Neuroscience at Scripps Florida, and Ayako Tonoki-Yamaguchi, a research associate in Davis's lab, took a close look at memory and memory traces in the brains of both young and old fruit flies.

What they found is that like other organisms—from mice to humans—there is a defect that occurs in memory with aging. In the case of the fruit fly, the ability to form memories lasting a few hours (intermediate-term memory) is lost due to age-related impairment of the function of certain neurons. Intriguingly, the scientists found that stimulating those same neurons can reverse these age-related memory defects.

"This study shows that once the appropriate neurons are identified in people, in principle at least one could potentially develop drugs to hit those neurons and rescue those memories affected by the aging process," Davis said. "In addition, the biochemistry underlying memory formation in fruit flies is remarkably conserved with that in humans so that everything we learn about memory formation in flies is likely applicable to human memory and the disorders of human memory."

While no one really understands what is altered in the brain during the aging process, in the current study the scientists were able to use functional cellular imaging to monitor the changes in the fly's neuron activity before and after learning to view those changes.

"We are able to peer down into the fly brain and see changes in the brain," Davis said. "We found changes that appear to reflect how intermediate-term memory is encoded in these neurons."

Olfactory memory, which was used by the scientists, is the most widely studied form of memory in fruit flies—basically pairing an odor with a mild electric shock. These tactics produce short-term memories that persist for around half an hour, intermediate-term memory that lasts a few hours, and long-term memory that persists for days.

The team found that in aged animals, the signs of encoded memory were absent after a few hours. In that way, the scientists also learned exactly which neurons in the fly are altered by aging to produce intermediate-term memory impairment. This advance, Davis notes, should greatly help scientists understand how aging alters neuronal function.

Intriguingly, the scientists took the work a step further and stimulated these neurons to see if the memory could be rescued. To do this, the scientists placed either cold-activated or heat-activated ion channels in the neurons known to become defective with aging and then used cold, or heat, to stimulate them. In both cases, the intermediate-term memory was successfully rescued.

More information: "Aging Impairs Intermediate-Term Behavioral Memory by Disrupting the Neuron Memory Trace," Proceedings of the National Academy of Sciences.

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Study shows difficulty in ability to discern facial symmetry helps explain 'beer goggles' effect

(Medical Xpress) -- It's a part of modern lore that doesn’t reflect well on our species, the idea that as people consume alcoholic beverages, they see those around them as becoming more attractive. It’s known as the “beer goggles” effect and has been used by members of both genders to help explain sexual escapades with another person who under normal circumstances, would not be someone they would consider for such activities. Now, new research helps to explain how and why this happens. L.G Halsey, J.W Huber, and J.C Hardwick have published the results of their research on the topic in the journal Addiction and suggest that one reason people find others more attractive when drinking is because alcohol impairs a person’s ability to detect facial symmetry.

The team notes that prior research has shown that a part of what makes people attractive to other people is the degree to which both sides of their faces match. The more symmetry the thinking goes, the better the gene pool, hence the more desirable they are as a potential mate. This they say, is one of the major factors that cause someone to see another as someone they would consider bedding. But, the whole system begins to go off track when alcohol is introduced. The researchers found that the more a person consumes, the more trouble they have figuring out symmetry in the faces of those around them, causing them to see everyone as better looking than they were sober. This, they say, accounts for the “beer goggles” effect.

To come to these conclusions, the team enlisted over 100 male and female volunteers from Roehampton University who were tasked with looking at photographs and rating the degree of attractiveness of the person shown. They were also asked to rate the degree of symmetry. Some volunteers were given drinks containing alcohol, while others were given drinks with no alcohol in them at all. The faces in the photographs had been premeasured for degree of symmetry and indeed some of the photographs had been altered to force the faces to be perfectly symmetrical.

After compiling the results, the team found that those people who were consuming alcohol showed less ability to discern symmetry and that their abilities grew worse as more alcohol was consumed. They also found that women’s abilities were more strongly impacted than men.

While these results clearly show a correlation between alcohol consumption and an ability to discern facial symmetry, and perhaps degree of attractiveness, the team isn’t suggesting that their results fully explain the “beer goggles” effect, more that their research adds a piece to the overall puzzle that is the decision making process and ultimate behavior of people when consuming alcohol.

More information: Does alcohol consumption really affect asymmetry perception? A three-armed placebo-controlled experimental study,Addiction, Accepted Article, DOI:10.1111/j.1360-0443.2012.03807.x

Abstract 

Aims:  A possible explanation for increased levels of attractiveness of faces when under the influence of alcohol is reduced ability to perceive bilateral asymmetry. This study tested the degree of preference by alcohol-dosed and non-alcohol-dosed participants for symmetrical faces and their ability to detect facial symmetry while controlling for other explanations. 

Design:  Volunteers were recruited to a random allocation experiment with three conditions: alcoholic drink (alcohol dosed), non-alcoholic drink (placebo) and diluted orange cordial (control). Data on concentration, personality and demographics were collected. Dependent variables were symmetry preference and detection. 

Setting:  Laboratory, University of Roehampton. 

Participants:  101 participants, mainly students (41 alcohol-dosed, 40 placebo, 20 control). 

Measurements:  Participants provided verbal responses to images of faces which were presented on a computer screen for 5 seconds each; the first task required a preference judgement and the second task consisted of a forced-choice response of whether a face was symmetrical or not. Levels of concentration, weight and level of alcohol-dose were measured, and demographics plus additional psychological and health information were collected using a computer based questionnaire. 

Findings:  In contrast to a previous investigation, there was no difference in symmetry preference between conditions (p = 0.846). In agreement with previous findings, participants who had not drunk alcohol were better at detecting whether a face was symmetrical or asymmetrical (p = 0.043). Measures of concentration did not differ between conditions (p = 0.214 to 0.438). Gender did not affect ability to detect symmetry in placebo or alcohol-dosed participants (p = 0.984, 0.499); however alcohol-dosed females were shown to demonstrate greater symmetry preference than alcohol-dosed males (p = 0.004). 

Conclusion:  People who are alcohol-dosed are subtly less able to perceive vertical, bilateral asymmetry in faces, with gender being a possible moderating factor.

© 2012 PhysOrg.com

"Study shows difficulty in ability to discern facial symmetry helps explain 'beer goggles' effect." April 2nd, 2012.http://medicalxpress.com/news/2012-04-difficulty-ability-discern-facial-symmetry.html

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Accentuating the positive memories for sleep

Sleep plays a powerful role in preserving our memories. But while recent research shows that wakefulness may cloud memories of negative or traumatic events, a new study has found that wakefulness also degrades positive memories. Sleep, it seems, protects positive memories just as it does negative ones, and that has important implications for the treatment of post-traumatic stress disorder.

"The study of how sleep helps us remember and process emotional information is still young," says Alexis Chambers of the University of Notre Dame. Past work has focused on the role of negative memories for sleep, in particular how insomnia is a healthy biological response for people to reduce negative memories and emotions associated with a traumatic event.

Two new studies presented this week at a meeting of cognitive neuroscientists in Chicago are exploring the flip side: how sleep treats the positive. "Only if we investigate all the possibilities within this field will we ever fully understand the processes underlying our sleep, memory, and emotions," Chambers says.

Protecting the positive

To test how sleep affects positive memories, Rebecca Spencer of the University of Massachusetts, Amherst, and her colleagues split 70 young adults into two groups, one that got to sleep overnight and one that had to stay awake. Both groups viewed images of positive items, such as puppies and flowers, and neutral items, such as furniture or dinner plates. The researchers then tested the participants' memories of and emotional reactions to the images 12 hours later, after either the period of sleep or wake.

They found that "sleep enhances our emotionally positive memories while these memories decay over wake," Spencer says. "Positive memories may even be prioritized for processing during sleep." But while people remembered the positive images more than the neutral ones, their emotional response to the positive images did not change over sleep versus wake. "It doesn't matter if you went to sleep or stayed awake – what you thought was a '9' – really great – you still think is a '9'," she says.

The results, she says, could have significant implications for treating post-traumatic stress disorder, as using wakefulness could have the unintended effect of degrading of positive memories in addition to negative memories. "It suggests that insomnia should be treated at some point after a traumatic event – perhaps a few days/weeks depending on the level of trauma – so that these positive memories can be strengthened and eventually outweigh the negative," Spencer says.

The study also reinforces the idea that with the standard ups and downs of our days, we should sleep to enhance our memories. "For mildly negative memories, we can learn something from them and we should remember them,"she says. "Moreover, sleep enhances memories for the positive events that we are exposed to and want to remember."

From an evolutionary perspective, sleep's role in protecting both positive and negative memories helps us to analyze and predict future events, Spencer says. People need to remember both the people and events that gave them bad experiences, as well as those that helped them and gave them good experiences.

Make Them Laugh

In another study, Chambers of the University of Notre Dame and colleagues, working under her adviser Jessica Payne, wanted to test if they could enhance positive memories over sleep by adding the element of humor. Chambers' team took Farside cartoons and showed both the originals and altered non-humorous versions to 66 participants before and after a period of wake or sleep. While participants more easily recalled the humorous versions of the cartoons, sleep had no effect on the type of cartoon recalled.

The fact that sleep did not impact such memories suggests something important about humor as a memory aid, Chambers says. "Sleep may be thought of as a way of aiding most memories since a period of sleep after learning is typically better for subsequent memory than a period of wake," she says "Similarly, humor may serve as a different, but possibly equal, aid for subsequent memory. Both methods help us remember things better in the future, but it appears that they work in independent ways."

Because there was an overall enhancement of memory for humorous over non-humorous cartoons, Chambers says, "it does appear that there is something about positive experiences that is worth remembering." Echoing Spencer's comments: "It could be that preserving such memories is adaptive to us, similar to the suggested survival value of preserving memories of negative experiences, such as a deadly snake to be avoided in the future."

Both studies – "Effects of Sleep on Memory and Reactivity for Positive Emotional Pictures," by Rebecca Spencer et al., and "Laugh Yourself to Sleep: The Role of Humor in the Investigation of Sleep's effects on Positive Memory" by Alexis Chambers et al. – will be presented in posters at the 19th annual meeting of the Cognitive Neuroscience Society (CNS). More than 1400 scientists are in attendance at the meeting in Chicago, IL, from March 31 to April 4, 2012.

Provided by Cognitive Neuroscience Society

"Accentuating the positive memories for sleep." April 2nd, 2012. http://medicalxpress.com/news/2012-04-accentuating-positive-memories.html

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Scientists achieve breakthrough in understanding sense of touch

The journal Cell's cover story features research findings by University of Wyoming neurobiologist Jeff Woodbury. He was part of a research team that is providing a new understanding of the sense of touch.

(Medical Xpress) -- A research team including University of Wyoming neurobiologist Jeff Woodbury has discovered a new technique to determine how the touch sensory system is organized in hairy skin, providing a new understanding of the sense of touch.

Their findings were selected to appear as the feature and cover article in Cell, one of the pre-eminent international journals in the biological sciences.

The research provides the first picture of how nerve cells that carry signals from hair on the skin are organized. Unlike all other senses, the skin is least amenable to study and has remained the most poorly understood.

"We have described the system that is in place to help explain how sensory information is processed to perceive the sense of touch," says Woodbury, an associate professor in the UW Department of Zoology and Physiology. He was part of a multidisciplinary research team led by David Ginty from Johns Hopkins University. Colleen Cassidy, a doctoral student in Woodbury's lab, was a co-author of the study, which also included colleagues from the Howard Hughes Medical Institute at Rockefeller University, University of Pennsylvania and University of Pittsburgh.

"We have also been able to identify how combinations of nerve cells respond to fine-tactile stimuli, so we can now really begin to tease apart the circuitry of touch sensation," Woodbury adds. "One of the real breakthroughs is that, for the first time in more than 200 years of study, we now know the specific functions of some of the many different kinds of nerve endings in the skin. This is truly exciting and a major advance."

Mice have several different types of hair follicles in their coat, each of which is linked to the central nervous system by low-threshold wire-like nerve cells that stretch all the way to the spinal cord. There, the myriad signals carried from the skin are integrated, processed and sent to the brain.

This network of nerve endings in the skin of most hairy mammals, including humans, allows them to perceive fine tactile sensations, such as a drop of rain or an insect landing on their skin. The researchers now have a better understanding of how this complex system is organized. Before this discovery, Woodbury says there was no way to see how all of these different nerve cells were arranged -- both in the skin and at the top of the spinal cord, where they end up.

The study, Woodbury says, opens doors to understanding not only touch, but skin senses such as temperature detection and pain.

"Touch is ultimately felt in the brain; it alerts us that something is going on," he says. "We have identified the logic of how this system is organized. We now know that each individual hair is a distinct sensory organ, and each one will detect different forces. A broad spectrum of frequencies within a given stimulus are ultimately recombined and analyzed until we become aware that something has happened, like a drop of rain or a light breeze."

Once the different sensory neurons are identified, researchers could test hypotheses about the role of these cells in the process of sensation.

"For example, researchers could study the animal, in the presence or absence of each of the different types of sensory cells, to determine differences in the animal's behavior," Woodbury says. "It will be possible to shut them off, take them out of the picture, to see how the animal responds to different types of stimulation. The key to understanding any system is first to gain a marker to identify all the different components, and we have made a major step in that direction."

Provided by University of Wyoming

"Scientists achieve breakthrough in understanding sense of touch." April 2nd, 2012. http://medicalxpress.com/news/2012-04-scientists-breakthrough.html

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