WASHINGTON - Beauty is in the brain of the beholder. Go to any museum and there will be men and women admiring paintings and sculpture. But it turns out they are thinking about the sight differently. Men process beauty on the right side of their brains, while women use their whole brain to do the job, researchers report in Tuesday's electronic edition of Proceedings of the National Academy of Science.
They even explain it differently.
Novelist Margaret Wolfe Hungerford: "Beauty is in the eye of the beholder."
Essayist David Hume: "Beauty in things exists merely in the mind which contemplates them."
Researchers were surprised by the finding.
"It is well known that there are differences between brain activity in women and men in cognitive tasks," said researcher Camilo J. Cela-Conde of the University of Baleares in Palma de Mallorca, Spain. "However, why should this kind of difference appear in the case of appreciation of beauty?"
The answer seems to be that when women consider a visual object they link it to language while men concentrate on the spatial aspects of the object, Cela-Conde said in an interview by e-mail.
He noted, however, that this doesn't explain why - and how - the human capacity to appreciate beauty evolved.
"The differences that we have found might relate to the different social roles that, hypothetically, men and women had during human evolution." he said.
The researchers tested 10 men and 10 women, showing them paintings and photos of urban scenes and landscapes, asking them to rate each scene as either "beautiful" or "not beautiful."
At the same time the scientists looked at images of the magnetic fields produced by electrical currents in the brains of the men and women.
For the first 300 milliseconds, there was no difference between male and female brains, and from 300 to 700 milliseconds activity was greater for objects that were rated as beautiful than for those that were not beautiful.
For both sexes the most active region was the parietal lobe that deals with visual perception, spatial orientation and information processing, but it was focused on the right side of the brain in men while both sides participated in women.
While there are differences between people as to what is beautiful and what isn't, Cela-Conde said they did not find identifiable differences related to sex.
"Any person can find beautiful a landscape, a building or a canvas that some others will find awful. But sex has little to do with those differences. Perhaps they relate with other variables, such as age or education." he said.
"It is curious that, using different neural networks, the final result is very similar in women and men. But this seems to be the case," Cela-Conde said.
He added: "Human nature is complex and difficult to study and understand. Nevertheless, thanks to scientific tools we are starting to know a bit more about some very important aspects of our nature."
Showing posts with label Biology. Show all posts
Showing posts with label Biology. Show all posts
Feb 19, 2009
Loneliness Affects How The Brain Operates
ScienceDaily (Feb. 17, 2009) — Social isolation affects how people behave as well as how their brains operate, a study at the University of Chicago shows.
The research, presented February 15 at a symposium, "Social Emotion and the Brain," at the annual meeting of the American Association for the Advancement of Science, is the first to use fMRI scans to study the connections between perceived social isolation (or loneliness) and activity in the brain. Combining fMRI scans with data relevant to social behavior is part of an emerging field examining brain mechanisms—an approach to psychology being pioneered at the University of Chicago.
Researchers found that the ventral striatum—a region of the brain associated with rewards—is much more activated in non-lonely people than in the lonely when they view pictures of people in pleasant settings. In contrast, the temporoparietal junction—a region associated with taking the perspective of another person—is much less activated among lonely than in the non-lonely when viewing pictures of people in unpleasant settings.
"Given their feelings of social isolation, lonely individuals may be left to find relative comfort in nonsocial rewards," said John Cacioppo, the Tiffany and Margaret Blake Professor in Psychology at the University. He spoke at the briefing along with Jean Decety, the Irving B. Harris Professor in Psychology and Psychiatry at the University.
The ventral striatum, which is critical to learning, is a key portion of the brain and is activated through primary rewards such as food and secondary rewards such as money. Social rewards and feelings of love also may activate the region.
Cacioppo, one of the nation's leading scholars on loneliness, has shown that loneliness undermines health and can be as detrimental as smoking. About one in five Americans experience loneliness, he said. Decety is one of the nation's leading researchers to use fMRI scans to explore empathy.
They were among five co-authors of a paper, "In the Eye of the Beholder: Individual Differences in Perceived Social Isolation Predict Regional Brain Activation to Social Stimuli," published in the current issue of the Journal of Cognitive Neuroscience.
In the study, 23 female undergraduates were tested to determine their level of loneliness. While in an fMRI scanner, the subjects were shown unpleasant pictures and human conflict as well as pleasant things such as money and happy people.
The subjects who rated as lonely were least likely to have strong activity in their ventral striata when shown pictures of people enjoying themselves.
Although loneliness may be influence brain activity, the research also suggests that activity in the ventral striatum may prompt feelings of loneliness, Decety said. "The study raises the intriguing possibility that loneliness may result from reduced reward-related activity in the ventral striatum in response to social rewards."
In addition to differing responses in the ventral striatum, the subjects also recorded differing responses in parts of the brain that indicated loneliness played a role in how their brain operates.
Joining Decety and Cacioppo in writing the Journal of Cognitive Science paper were Catherine Norris, Assistant Professor of Psychology at Dartmouth College; George Monteleone, a graduate student at the University of Chicago; and Howard Nusbaum, Chair of Psychology at the University of Chicago.
Decety and Cacioppo discussed the new field of brain mechanism in a paper in the current issue of Perspectives on Psychological Science. The new field extends the work of Charles Darwin, who "regarded the brain as a product of evolution and the science of psychology as concerned with these foundations," they wrote.
By studying brain mechanisms, researchers hope to gain new insights by examining mental activities surrounding consciousness, perception and thought through an understanding of how columns of neurons stacked next to each other form elementary circuits to function as a unit, they wrote.
New visualization tools such as three-dimensional imaging will help scholars develop a new way of studying psychology, they said.
"Psychological science in the 21st century can, and should, become not only the science of overt behavior, and not only the science of the mind, but also the science of the brain," they concluded.
The research, presented February 15 at a symposium, "Social Emotion and the Brain," at the annual meeting of the American Association for the Advancement of Science, is the first to use fMRI scans to study the connections between perceived social isolation (or loneliness) and activity in the brain. Combining fMRI scans with data relevant to social behavior is part of an emerging field examining brain mechanisms—an approach to psychology being pioneered at the University of Chicago.
Researchers found that the ventral striatum—a region of the brain associated with rewards—is much more activated in non-lonely people than in the lonely when they view pictures of people in pleasant settings. In contrast, the temporoparietal junction—a region associated with taking the perspective of another person—is much less activated among lonely than in the non-lonely when viewing pictures of people in unpleasant settings.
"Given their feelings of social isolation, lonely individuals may be left to find relative comfort in nonsocial rewards," said John Cacioppo, the Tiffany and Margaret Blake Professor in Psychology at the University. He spoke at the briefing along with Jean Decety, the Irving B. Harris Professor in Psychology and Psychiatry at the University.
The ventral striatum, which is critical to learning, is a key portion of the brain and is activated through primary rewards such as food and secondary rewards such as money. Social rewards and feelings of love also may activate the region.
Cacioppo, one of the nation's leading scholars on loneliness, has shown that loneliness undermines health and can be as detrimental as smoking. About one in five Americans experience loneliness, he said. Decety is one of the nation's leading researchers to use fMRI scans to explore empathy.
They were among five co-authors of a paper, "In the Eye of the Beholder: Individual Differences in Perceived Social Isolation Predict Regional Brain Activation to Social Stimuli," published in the current issue of the Journal of Cognitive Neuroscience.
In the study, 23 female undergraduates were tested to determine their level of loneliness. While in an fMRI scanner, the subjects were shown unpleasant pictures and human conflict as well as pleasant things such as money and happy people.
The subjects who rated as lonely were least likely to have strong activity in their ventral striata when shown pictures of people enjoying themselves.
Although loneliness may be influence brain activity, the research also suggests that activity in the ventral striatum may prompt feelings of loneliness, Decety said. "The study raises the intriguing possibility that loneliness may result from reduced reward-related activity in the ventral striatum in response to social rewards."
In addition to differing responses in the ventral striatum, the subjects also recorded differing responses in parts of the brain that indicated loneliness played a role in how their brain operates.
Joining Decety and Cacioppo in writing the Journal of Cognitive Science paper were Catherine Norris, Assistant Professor of Psychology at Dartmouth College; George Monteleone, a graduate student at the University of Chicago; and Howard Nusbaum, Chair of Psychology at the University of Chicago.
Decety and Cacioppo discussed the new field of brain mechanism in a paper in the current issue of Perspectives on Psychological Science. The new field extends the work of Charles Darwin, who "regarded the brain as a product of evolution and the science of psychology as concerned with these foundations," they wrote.
By studying brain mechanisms, researchers hope to gain new insights by examining mental activities surrounding consciousness, perception and thought through an understanding of how columns of neurons stacked next to each other form elementary circuits to function as a unit, they wrote.
New visualization tools such as three-dimensional imaging will help scholars develop a new way of studying psychology, they said.
"Psychological science in the 21st century can, and should, become not only the science of overt behavior, and not only the science of the mind, but also the science of the brain," they concluded.
Feb 18, 2009
Varying Sweat Scents Are Noted by Women
By NICHOLAS BAKALAR
Published: February 16, 2009
Men’s sweat smells different when they are sexually aroused, and women can tell the difference, a new study finds — even though they are not conscious of it.
The sexual activity of animals is affected by odor, but little is known about the phenomenon in humans. Although all three types of sweat glands respond to emotion and sexual arousal, no one has ever convincingly established that body odor plays a significant role in human sexual relations or reproduction.
“In surveys, people say that body odors are important in selecting a mate,” said Denise Chen, the lead author of the study. “But we don’t really know exactly what role body odors play in human sexuality.”
The report, published in the January issue of The Journal of Neuroscience, suggests that women distinguish the odor of sexual sweat from neutral sweat by processing the odors in different parts of the brain.
The researchers had 20 heterosexual male volunteers hold absorbent pads in their armpits while they watched 20 minutes of an erotic film, and then again while they watched a 20-minute film with neutral content. Then they had 19 heterosexual women smell the sexual sweat and neutral sweat pads from the three men who reported the highest level of sexual arousal.
The women also sniffed two additional pads, one moistened with androstadienone, a hormone produced naturally in sweat that some believe is a sex pheromone, and the other a control pad with a slight neutral odor. The pads were presented randomly, and the women were asked to rate the pleasantness and intensity of the odors. While the women sniffed, researchers monitored their brain activity with functional magnetic resonance imaging.
Adam K. Anderson, an assistant professor of psychology at the University of Toronto who was not involved in the study, called the methodology impressive.
“What’s being taken as a stimulus is not some chemical created in a lab — it’s real sweat from people who are sexually aroused,” said Dr. Anderson, who does research in human olfaction. “What a scientist would normally do is try to distill the active component of that very complex perfume. They didn’t do that. They compared the complex sweat to the sex pheromone and found that the brain was much more responsive.”
In their verbal responses, all but two subjects denied smelling any sweat, or anything human, and none verbally distinguished the sexual from the neutral sweat. But their brain activity told a different story.
Two regions of the brain, the right orbitofrontal cortex and the right fusiform region, responded significantly more to the sexual sweat of men than to any of the other smells.
Dr. Chen, an assistant professor of psychology at Rice University, said that only one brain area, the hypothalamus, is known to be important in sexual motivation and behavior, and that region did not respond to the odors. But the researchers did find that the brain somehow recognizes social or emotional information contained in sexual sweat, treating it differently from other odors. In this sense, they conclude, humans communicate with smell.
No man should imagine that based on these conclusions he can improve his sex life by refraining from bathing.
“Our findings do not convey the suggestion that human sweat is an aphrodisiac,” Dr. Chen wrote in an e-mail message.
So what does the scent of a man mean to a woman? Dr. Anderson suggested there was no reason to conclude that men now know what women want. “They didn’t find activations of typical reward centers or regions associated with pleasure,” he said. “It’s just as likely that their brains are picking up a man in heat that they are not particularly attracted to.”
Published: February 16, 2009
Men’s sweat smells different when they are sexually aroused, and women can tell the difference, a new study finds — even though they are not conscious of it.
The sexual activity of animals is affected by odor, but little is known about the phenomenon in humans. Although all three types of sweat glands respond to emotion and sexual arousal, no one has ever convincingly established that body odor plays a significant role in human sexual relations or reproduction.
“In surveys, people say that body odors are important in selecting a mate,” said Denise Chen, the lead author of the study. “But we don’t really know exactly what role body odors play in human sexuality.”
The report, published in the January issue of The Journal of Neuroscience, suggests that women distinguish the odor of sexual sweat from neutral sweat by processing the odors in different parts of the brain.
The researchers had 20 heterosexual male volunteers hold absorbent pads in their armpits while they watched 20 minutes of an erotic film, and then again while they watched a 20-minute film with neutral content. Then they had 19 heterosexual women smell the sexual sweat and neutral sweat pads from the three men who reported the highest level of sexual arousal.
The women also sniffed two additional pads, one moistened with androstadienone, a hormone produced naturally in sweat that some believe is a sex pheromone, and the other a control pad with a slight neutral odor. The pads were presented randomly, and the women were asked to rate the pleasantness and intensity of the odors. While the women sniffed, researchers monitored their brain activity with functional magnetic resonance imaging.
Adam K. Anderson, an assistant professor of psychology at the University of Toronto who was not involved in the study, called the methodology impressive.
“What’s being taken as a stimulus is not some chemical created in a lab — it’s real sweat from people who are sexually aroused,” said Dr. Anderson, who does research in human olfaction. “What a scientist would normally do is try to distill the active component of that very complex perfume. They didn’t do that. They compared the complex sweat to the sex pheromone and found that the brain was much more responsive.”
In their verbal responses, all but two subjects denied smelling any sweat, or anything human, and none verbally distinguished the sexual from the neutral sweat. But their brain activity told a different story.
Two regions of the brain, the right orbitofrontal cortex and the right fusiform region, responded significantly more to the sexual sweat of men than to any of the other smells.
Dr. Chen, an assistant professor of psychology at Rice University, said that only one brain area, the hypothalamus, is known to be important in sexual motivation and behavior, and that region did not respond to the odors. But the researchers did find that the brain somehow recognizes social or emotional information contained in sexual sweat, treating it differently from other odors. In this sense, they conclude, humans communicate with smell.
No man should imagine that based on these conclusions he can improve his sex life by refraining from bathing.
“Our findings do not convey the suggestion that human sweat is an aphrodisiac,” Dr. Chen wrote in an e-mail message.
So what does the scent of a man mean to a woman? Dr. Anderson suggested there was no reason to conclude that men now know what women want. “They didn’t find activations of typical reward centers or regions associated with pleasure,” he said. “It’s just as likely that their brains are picking up a man in heat that they are not particularly attracted to.”
Feb 2, 2009
Conference: The Evolution Of Human Aggression, Feb. 25-27
As scientists celebrate 2009 as the bicentennial of Charles Darwin's birth, experts in anthropology, biology, psychology and other fields will gather at the University of Utah Feb. 25-27 to debate how evolution has shaped human aggression and violence, from war to domestic abuse and homicide.
"What evolutionary forces underlie human violence, and how can we use this knowledge to promote a more peaceful society?" asks Elizabeth Cashdan, a conference organizer and professor and chair of anthropology at the University of Utah.
The conference - titled "The Evolution of Human Aggression: Lessons for Today's Conflicts" - is presented by the university's Barbara L. and Norman C. Tanner Center for Nonviolent Human Rights Advocacy.
It will be held at various locations - mostly at Fort Douglas on the University of Utah campus - from Wednesday evening, Feb. 25 through Friday afternoon, Feb. 27.
The public and news media are invited to attend the free conference.
Conference highlights include keynote lectures on the evolution of peacemaking among primates and the relationship between homicide and economic competition; panel discussions on conflict and reconciliation among great apes, violence and warfare, hormones and human aggression, and domestic violence; a scientific poster session; and a community forum on violence.
"This conference helps to bring science fully into the conversation about violence, conflict management and peacemaking," says communication Professor George Cheney, director of the Tanner Center for Nonviolent Human Rights Advocacy. "This gathering, which is the third in our annual series, will include provocative presentations, lively debate and a roundtable discussion of how current research might be used to reduce violence in our own and other communities."
200 Years after Darwin's Birth, Evolution has Lessons for Modern Conflicts
"Curbing human violence is one of the great challenges humanity faces in the 21st century," says David Carrier, a conference organizer and professor of biology at the University of Utah. "Many aspects of human aggression will be addressed at this conference: warfare, homicide, child abuse and domestic violence. We encourage public attendance because an increased understanding of the evolutionary basis of human aggression may help individuals prevent violence in their own lives and the lives of their friends and family members."
"Every adult on the planet has experienced anger," says Stephen Downes, a University of Utah philosophy professor and a conference organizer. "Some of us have committed violent acts against others out of anger. Why we feel this way and why some of us act in the way we do is a question that has consumed students of human nature for thousands of years."
"Evolutionary theory gives some of the most revealing insights into this issue," he adds. "Bringing together a group of the world's leading experts on evolution and aggression is an appropriate tribute to Darwin in this 'Darwin year'" - the 200th anniversary of Darwin's birth and 150th anniversary of his "On the Origin of Species."
While the modern view has grown more complex, Cashdan says that for decades, "there has been a lot of unproductive debate between people who argue that 'humans are naturally aggressive' and others who contend that 'humans are naturally peaceful.' There is plenty of evidence to support both claims: violence, reconciliation and cooperation are all part of human nature."
Cashdan adds: "We begin with the working assumption that natural selection has shaped human nature to be both violent and peaceful, and ask how evolutionary arguments can help us to understand the factors that lead to both violent and peaceful outcomes. This can help show which policy changes are likely to be successful, and where we can most usefully intervene to allow the better angels of our nature to prevail."
"What evolutionary forces underlie human violence, and how can we use this knowledge to promote a more peaceful society?" asks Elizabeth Cashdan, a conference organizer and professor and chair of anthropology at the University of Utah.
The conference - titled "The Evolution of Human Aggression: Lessons for Today's Conflicts" - is presented by the university's Barbara L. and Norman C. Tanner Center for Nonviolent Human Rights Advocacy.
It will be held at various locations - mostly at Fort Douglas on the University of Utah campus - from Wednesday evening, Feb. 25 through Friday afternoon, Feb. 27.
The public and news media are invited to attend the free conference.
Conference highlights include keynote lectures on the evolution of peacemaking among primates and the relationship between homicide and economic competition; panel discussions on conflict and reconciliation among great apes, violence and warfare, hormones and human aggression, and domestic violence; a scientific poster session; and a community forum on violence.
"This conference helps to bring science fully into the conversation about violence, conflict management and peacemaking," says communication Professor George Cheney, director of the Tanner Center for Nonviolent Human Rights Advocacy. "This gathering, which is the third in our annual series, will include provocative presentations, lively debate and a roundtable discussion of how current research might be used to reduce violence in our own and other communities."
200 Years after Darwin's Birth, Evolution has Lessons for Modern Conflicts
"Curbing human violence is one of the great challenges humanity faces in the 21st century," says David Carrier, a conference organizer and professor of biology at the University of Utah. "Many aspects of human aggression will be addressed at this conference: warfare, homicide, child abuse and domestic violence. We encourage public attendance because an increased understanding of the evolutionary basis of human aggression may help individuals prevent violence in their own lives and the lives of their friends and family members."
"Every adult on the planet has experienced anger," says Stephen Downes, a University of Utah philosophy professor and a conference organizer. "Some of us have committed violent acts against others out of anger. Why we feel this way and why some of us act in the way we do is a question that has consumed students of human nature for thousands of years."
"Evolutionary theory gives some of the most revealing insights into this issue," he adds. "Bringing together a group of the world's leading experts on evolution and aggression is an appropriate tribute to Darwin in this 'Darwin year'" - the 200th anniversary of Darwin's birth and 150th anniversary of his "On the Origin of Species."
While the modern view has grown more complex, Cashdan says that for decades, "there has been a lot of unproductive debate between people who argue that 'humans are naturally aggressive' and others who contend that 'humans are naturally peaceful.' There is plenty of evidence to support both claims: violence, reconciliation and cooperation are all part of human nature."
Cashdan adds: "We begin with the working assumption that natural selection has shaped human nature to be both violent and peaceful, and ask how evolutionary arguments can help us to understand the factors that lead to both violent and peaceful outcomes. This can help show which policy changes are likely to be successful, and where we can most usefully intervene to allow the better angels of our nature to prevail."
Discovery Of Brain's Memory 'Buffer' In Single Cells
Individual nerve cells in the front part of the brain can hold traces of memories on their own for as long as a minute and possibly longer, researchers at UT Southwestern Medical Center have found.
The study, available online and appearing in the February issue of Nature Neuroscience, is the first to identify the specific signal that establishes nonpermanent cellular memory and reveals how the brain holds temporary information. It has implications for addiction, attention disorders and stress-related memory loss, said Dr. Don Cooper, assistant professor of psychiatry at UT Southwestern and senior author of the study conducted in mice.
Researchers have known that permanent memories are stored when the excitatory amino acid glutamate activates ion channels on nerve cells in the brain to reorganize and strengthen the cells' connections with one another. But this process takes minutes to hours to turn on and off and is too slow to buffer, or temporarily hold, rapidly incoming information.
The researchers found that rapid-fire inputs less than a second long initiate a cellular memory process in single cells lasting as long as minute, a process called metabotropic glutamate transmission. This transmission in the most highly evolved brain region holds moment-to-moment information.
These cellular findings have implications for how the human brain stores rapidly changing information, like the temporary memory a card shark uses when counting cards in a game of Black Jack and, as casinos have figured out, it is the memory that is most sensitive to the disruptive effects of alcohol and noisy distractions, Dr. Cooper said.
"It's more like RAM [random access memory] on a computer than memory stored on a disk," Dr. Cooper said. "The memory on the disk is more permanent and you can go back and access the same information repeatedly. RAM memory is rewritable temporary storage that allows multitasking."
The researchers identified in mice a specific metabotropic glutamate receptor called mGluR5 that, when turned on, starts a signaling cascade using calcium to hold a memory trace. This fast, short-term memory process happens inside individual cells; with long-term memory, additional proteins cause slow reorganization between cells in a network to establish a permanent memory.
Researchers examined brain cells from mice using nanoscale electrodes to measure the memory formation process.
To further understand how this short-term memory process relates to addiction, researchers applied the neurochemical dopamine to the memory buffer nerve cells. Dopamine is normally needed at an optimal level for an individual to focus attention and engage in fast decision-making memory, but drugs of abuse overload the brain with a surge of dopamine. In the study, researchers found that an experimental drug that activates a specific type of dopamine receptor "focused" the nerve cells, making the memory trace less susceptible to distraction.
When researchers employed an animal model of drug addiction using cocaine, they also found that repeated exposure to addictive levels of cocaine reduced memory trace activation in the memory buffer cells. When researchers then activated dopamine signaling in the "addicted" animals, essentially adding more dopamine to their systems, no focusing effect was observed.
"This makes sense because we know from human and animal models of addiction, when a decision using working memory has to be made, brain imaging shows a deficit in the same area of the brain we looked at," Dr. Cooper said. "It all fits together."
Researchers next plan to identify the ion channel responsible for holding and regenerating a memory trace. Their goal is to develop new pharmacological and genetic tools that will allow them to manipulate and possibly expand decision-making memory capacity.
"If we can identify and manipulate the molecular components of memory, we can develop drugs that boost the ability to maintain this memory trace to hopefully allow a person to complete tasks without being distracted," Dr. Cooper said. "For the person addicted to drugs, we could strengthen this part of the brain involved with decision-making, allowing them to ignore impulses and weigh negative consequences of their behavior before they abuse drugs."
Other researchers from UT Southwestern involved in the study in Dr. Cooper's laboratory were Dr. Fang-Min Lu, assistant instructor of psychiatry; Melissa Fowler, a graduate student in psychiatry; Christopher Phillips, a medical student; and Emin Ozkan, student research assistant in physiology. Lead author Kyriaki Sidiropoulou from Rosalind Franklin University of Medicine and Science's Chicago Medical School and researchers from Ohio State University also participated in the study.
The study was funded by the National Institute on Drug Abuse; National Alliance for Research on Schizophrenia and Depression; the Alexander S. Onassis Public Benefit Foundation; and the Department of Veterans Affairs.
----------------------------
Article adapted by Medical News Today from original press release.
The study, available online and appearing in the February issue of Nature Neuroscience, is the first to identify the specific signal that establishes nonpermanent cellular memory and reveals how the brain holds temporary information. It has implications for addiction, attention disorders and stress-related memory loss, said Dr. Don Cooper, assistant professor of psychiatry at UT Southwestern and senior author of the study conducted in mice.
Researchers have known that permanent memories are stored when the excitatory amino acid glutamate activates ion channels on nerve cells in the brain to reorganize and strengthen the cells' connections with one another. But this process takes minutes to hours to turn on and off and is too slow to buffer, or temporarily hold, rapidly incoming information.
The researchers found that rapid-fire inputs less than a second long initiate a cellular memory process in single cells lasting as long as minute, a process called metabotropic glutamate transmission. This transmission in the most highly evolved brain region holds moment-to-moment information.
These cellular findings have implications for how the human brain stores rapidly changing information, like the temporary memory a card shark uses when counting cards in a game of Black Jack and, as casinos have figured out, it is the memory that is most sensitive to the disruptive effects of alcohol and noisy distractions, Dr. Cooper said.
"It's more like RAM [random access memory] on a computer than memory stored on a disk," Dr. Cooper said. "The memory on the disk is more permanent and you can go back and access the same information repeatedly. RAM memory is rewritable temporary storage that allows multitasking."
The researchers identified in mice a specific metabotropic glutamate receptor called mGluR5 that, when turned on, starts a signaling cascade using calcium to hold a memory trace. This fast, short-term memory process happens inside individual cells; with long-term memory, additional proteins cause slow reorganization between cells in a network to establish a permanent memory.
Researchers examined brain cells from mice using nanoscale electrodes to measure the memory formation process.
To further understand how this short-term memory process relates to addiction, researchers applied the neurochemical dopamine to the memory buffer nerve cells. Dopamine is normally needed at an optimal level for an individual to focus attention and engage in fast decision-making memory, but drugs of abuse overload the brain with a surge of dopamine. In the study, researchers found that an experimental drug that activates a specific type of dopamine receptor "focused" the nerve cells, making the memory trace less susceptible to distraction.
When researchers employed an animal model of drug addiction using cocaine, they also found that repeated exposure to addictive levels of cocaine reduced memory trace activation in the memory buffer cells. When researchers then activated dopamine signaling in the "addicted" animals, essentially adding more dopamine to their systems, no focusing effect was observed.
"This makes sense because we know from human and animal models of addiction, when a decision using working memory has to be made, brain imaging shows a deficit in the same area of the brain we looked at," Dr. Cooper said. "It all fits together."
Researchers next plan to identify the ion channel responsible for holding and regenerating a memory trace. Their goal is to develop new pharmacological and genetic tools that will allow them to manipulate and possibly expand decision-making memory capacity.
"If we can identify and manipulate the molecular components of memory, we can develop drugs that boost the ability to maintain this memory trace to hopefully allow a person to complete tasks without being distracted," Dr. Cooper said. "For the person addicted to drugs, we could strengthen this part of the brain involved with decision-making, allowing them to ignore impulses and weigh negative consequences of their behavior before they abuse drugs."
Other researchers from UT Southwestern involved in the study in Dr. Cooper's laboratory were Dr. Fang-Min Lu, assistant instructor of psychiatry; Melissa Fowler, a graduate student in psychiatry; Christopher Phillips, a medical student; and Emin Ozkan, student research assistant in physiology. Lead author Kyriaki Sidiropoulou from Rosalind Franklin University of Medicine and Science's Chicago Medical School and researchers from Ohio State University also participated in the study.
The study was funded by the National Institute on Drug Abuse; National Alliance for Research on Schizophrenia and Depression; the Alexander S. Onassis Public Benefit Foundation; and the Department of Veterans Affairs.
----------------------------
Article adapted by Medical News Today from original press release.
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