Louis J. Sheehan, Esquire It sounds like a lost episode of The Twilight Zone. A man enters a laboratory, dons a special headset and shakes hands with a woman sitting across from him. In a matter of seconds, he feels like he’s inside the woman’s skin, reaching out and grasping his own hand.
Strange as it sounds, neuroscientists have induced this phenomenon in a series of volunteers. People can experience the illusion that either a mannequin or another person’s body is their own body, says Valeria Petkova of the Karolinska Institute in Stockholm. She and Karolinska colleague Henrik Ehrsson call this reaction the “body-swap illusion.”
“Our subjects experienced this illusion as being exciting and strange, and often said that they wanted to come back and try it again,” says Petkova, who reported the findings November 17 at the annual meeting of the Society for Neuroscience.
Illusory body-swapping could provide a new tool for studying the nature of self-identity and psychiatric disorders that involve distortions of body image, she suggests. This phenomenon might also be tapped to enhance user control over virtual reality applications and to prompt a person’s sense of really being part of a virtual world.
Volunteers experienced the body-swap illusion by receiving simultaneous visual and motor input from another’s body. In one experiment, each participant stood across from a male mannequin, and in another experiment volunteers faced a female experimenter. A headset covering participants’ eyes displayed a three-dimensional view of the other’s visual perspective, transmitted from a small video camera positioned on the mannequin’s or the woman’s head.
In the mannequin situation, an experimenter simultaneously touched the participant’s belly and the mannequin’s belly with separate probes. So the volunteer felt a poking in the abdomen but saw the poking happen as if he or she were the mannequin. In the real-person situation, participant and experimenter shook hands. Thus, while volunteers felt the sensation of hand shaking, it appeared to them that they were shaking their own hand. After 10 to 12 seconds of abdominal touch or hand-shaking, male and female participants spontaneously had the experience of looking out from the body of the male mannequin or the female experimenter. http://Louissheehan.BraveDiary.com They literally felt that they were in the mannequin’s body getting poked or had embodied the female experimenter and were shaking their own hands.
“In the body-swap illusion, we can see that multisensory information powerfully affects the brain,” says neuroscientist Patrick Haggard of University College London, who was not part of the research team.
Petkova and Ehrsson first confirmed that 16 male and 16 female volunteers experienced an illusory body-swap with a mannequin. After undergoing the procedure, participants indicated on a questionnaire that they had experienced the mannequin’s body as their own. They didn’t feel that they had become plastic like a mannequin, Petkova notes. Volunteers reported having had an expectation that, if they moved, the mannequin’s body would move accordingly.
In a subsequent experiment, the researchers found that 10 volunteers experiencing a body-swap with a mannequin displayed elevated electrical responses in the skin on their fingertips — a physiological indication of heightened emotion — when a knife was passed just over the mannequin’s arm. No such response occurred when a knife was passed just over volunteers’ arms during the illusion.
In a third experiment, 12 volunteers experiencing a body-swap with a female experimenter exhibited comparable physiological signs of emotional arousal when a knife was passed just over the experimenter’s arm, but not just over their own arms.
Gender had no affect on the illusion. Men had no difficulty experiencing a body-swap with a female experimenter, Petkova notes. Women readily experienced the illusion of being in a male mannequin’s body.
“This illusion is so strong that one can face one’s physical body and shake hands with oneself while still experiencing owning another person’s body,” Petkova says.
When a researcher stroked a brush along a volunteer’s own arm, the body-swap illusion vanished. In this way, each participant’s personal sense of touch became disengaged from the other individual’s visual perspective, Petkova proposes.
The new findings build on Ehrsson’s earlier research documenting a “rubber-hand illusion.” To induce that effect, a rubber hand is plausibly positioned on a table to extend from a volunteer’s outstretched arm, while the person’s actual hand is hidden. As an experimenter strokes the rubber hand with a brush, the volunteer eventually experiences the fake hand as his or her own and feels the sensation of being stroked.
Thursday, April 30, 2009
Wednesday, April 15, 2009
findings 3.fin.0002003 Louis J. Sheehan, Esquire
Sleep is a mystery. Louis J. Sheehan, Esquire Although no one knows exactly why, it’s required for good health. But now, scientists have found a surprisingly clear connection between sleep and a healthy body: the regulation of sugar levels in the blood. http://LOUIS-J-SHEEHAN.ORG The new studies, all online December 7 in Nature Genetics, describe the first genetic link between sleep and type 2 diabetes, a disease marked by high blood sugar levels.
In the United States, the number of people with type 2 diabetes is increasing, according to a 2006 paper in the journal Circulation; while the average amount people sleep is dwindling, according to a sleep survey by the Centers for Disease Control and Prevention. The investigations by three international teams of researchers suggest the trends of rising diabetes and falling sleep are linked via a protein that senses the sleep-inducing hormone melatonin. The research places bodily rhythms, including the clock that sets human sleep cycles, squarely in the blood sugar business. http://LOUIS-J-SHEEHAN.ORG
This newfound link between melatonin and type 2 diabetes intrigues sleep researchers like Orfeu Buxton at Harvard Medical School in Boston, who was not involved with the new work. “This is really breakthrough stuff,” he says.
The findings fill in some of the molecular details of how sleep can change blood sugar levels. The key, it appears, is a melatonin receptor, a protein on the outside of cells that senses melatonin in the blood and triggers sleep- or wake-related changes in cells.
Human bodies have a clock, an internal rhythm that dictates when to fall asleep and when to get up. Molecular timekeepers, made and degraded every 24 hours, set this daily cycle. When part of the ticking molecular clock goes awry, sleep schedules change.
Disordered sleep can spark a constellation of intertwined pathologies: Studies in humans have shown that depression, obesity, weakened immune system function and even death are all correlated with a lack of shut-eye. Population studies have shown that diabetes rates rise as sleep declines. http://LOUIS-J-SHEEHAN.ORG While these data provide compelling reasons to get eight hours of quality sleep every night, they couldn’t explain how diabetes might be influenced by sleep.
The three new genomic studies show that melatonin, a major regulator of the body’s sleep clock, is closely linked to increased glucose levels and diabetes. Best known for its sleep-inducing properties, melatonin is sold as an over-the-counter, nutritional supplement to aid sleep. Melatonin levels in the body are tied to daylight: When the lights go down, melatonin levels rise and drowsiness soon follows.
The finding identifies melatonin as a “fascinating new target” for diabetes treatments, says endocrinologist Leif Groop of Lund University in Malmö, Sweden, and a coauthor on two of the new reports.
Two studies, one listing 109 coauthors, analyzed data from earlier studies that had measured blood sugar levels and had collected DNA samples from their participants — the larger study analyzed data from 36,610 people and the other from 2,151 people. All participants were of European descent.
In both studies, comparing the DNA sequences of participants who had high blood sugar levels with the DNA of those who had normal blood sugar levels turned up a surprise. In both studies, MTNR1B, a gene encoding a melatonin receptor, caught researchers’ attention. People with high blood sugar levels, and thus diabetes, were much more likely to have a change in a single DNA base, or letter, within the gene than were those with healthy blood sugar levels.
"The finding that the melatonin receptor has an influence on diabetes was unexpected,” Groop says.
A third paper, which analyzed results from two large studies of over 18,000 participants, took the findings a step further. The researchers showed that the same DNA change in MTNR1B identified in the other two studies — a seemingly innocuous G instead of the more common C — was correlated with high blood sugar levels, low insulin levels and most important, a greater risk of developing type 2 diabetes during the multiyear studies.
The scientists, including Groop, also did experiments that looked at how melatonin might directly interact with insulin-producing cells.
The melatonin receptor was thought to be primarily expressed in the brain — where the body’s master clock resides. Groop and colleagues now show that insulin-producing cells, called beta-cells, in the pancreas of mice, rats and humans, also have the melatonin receptor.
The presence of the melatonin receptor on the insulin-secreting cells makes it more likely that the receptor is directly controlling the output of insulin. When scientists added melatonin to human beta-cells in the lab, insulin production went down. That melatonin and insulin are connected makes sense, because in the dead of night, when melatonin levels are high, the need for insulin should be low. Researchers don’t yet know how melatonin levels are different in sleep-deprived people, and how this difference could lead to decreased insulin production.
The tie between sleep and blood sugar didn’t come as a surprise to some sleep researchers. Buxton says that evidence has accumulated for years on the relationship between sleep and blood sugar levels. “However, such a direct role for melatonin was very surprising,” he says
Researcher James Gangwisch of Columbia University in New York City says the identification of the melatonin receptor as an important regulator of blood sugar “fits well” with earlier studies looking at the effects of poor sleep on blood sugar levels.
A 2007 study found that people who get less than five hours of sleep a night were significantly more likely to have type 2 diabetes. Experiments on sleep in the lab confirm this trend: Healthy young adults who were prevented from entering deep sleep for just three nights couldn’t properly regulate blood sugar levels, a 2008 study shows. What’s more, the subjects became more resistant to insulin during the study, eventually reaching the levels of insulin sensitivity that resemble the insulin resistance of diabetic people.
Sleep-deprived subjects, Gangwisch says, crave starchy, sweet foods and don’t regulate blood sugar well. “We know it’s true, but the question is why.”
“This paper ties those two things together,” says Gonçalo Abecasis of the University of Michigan School of Public Health, Ann Arbor, coauthor of one of the studies. “Sleep disrupts the circadian clock, and the melatonin receptor disrupts the circadian clock. These are two different ways to interrupt the clock, but both lead to the same endpoint of diabetes.”
“These findings raise more exciting questions than they answer,” says Buxton. But he cautions that the data on melatonin’s impact on insulin-producing cells in humans is still early. Many more studies are needed before scientists will fully understand how melatonin affects blood sugar levels and type 2 diabetes. Louis J. Sheehan, Esquire
Groop agrees, and points to the need for more basic studies on the melatonin receptor and clinical tests of glucose levels in people who have been given melatonin supplements.
People taking melatonin to aid sleep may be just such a group. Says Abecasis, “I think it would be interesting to track incidences of diabetes in such people.”
In the United States, the number of people with type 2 diabetes is increasing, according to a 2006 paper in the journal Circulation; while the average amount people sleep is dwindling, according to a sleep survey by the Centers for Disease Control and Prevention. The investigations by three international teams of researchers suggest the trends of rising diabetes and falling sleep are linked via a protein that senses the sleep-inducing hormone melatonin. The research places bodily rhythms, including the clock that sets human sleep cycles, squarely in the blood sugar business. http://LOUIS-J-SHEEHAN.ORG
This newfound link between melatonin and type 2 diabetes intrigues sleep researchers like Orfeu Buxton at Harvard Medical School in Boston, who was not involved with the new work. “This is really breakthrough stuff,” he says.
The findings fill in some of the molecular details of how sleep can change blood sugar levels. The key, it appears, is a melatonin receptor, a protein on the outside of cells that senses melatonin in the blood and triggers sleep- or wake-related changes in cells.
Human bodies have a clock, an internal rhythm that dictates when to fall asleep and when to get up. Molecular timekeepers, made and degraded every 24 hours, set this daily cycle. When part of the ticking molecular clock goes awry, sleep schedules change.
Disordered sleep can spark a constellation of intertwined pathologies: Studies in humans have shown that depression, obesity, weakened immune system function and even death are all correlated with a lack of shut-eye. Population studies have shown that diabetes rates rise as sleep declines. http://LOUIS-J-SHEEHAN.ORG While these data provide compelling reasons to get eight hours of quality sleep every night, they couldn’t explain how diabetes might be influenced by sleep.
The three new genomic studies show that melatonin, a major regulator of the body’s sleep clock, is closely linked to increased glucose levels and diabetes. Best known for its sleep-inducing properties, melatonin is sold as an over-the-counter, nutritional supplement to aid sleep. Melatonin levels in the body are tied to daylight: When the lights go down, melatonin levels rise and drowsiness soon follows.
The finding identifies melatonin as a “fascinating new target” for diabetes treatments, says endocrinologist Leif Groop of Lund University in Malmö, Sweden, and a coauthor on two of the new reports.
Two studies, one listing 109 coauthors, analyzed data from earlier studies that had measured blood sugar levels and had collected DNA samples from their participants — the larger study analyzed data from 36,610 people and the other from 2,151 people. All participants were of European descent.
In both studies, comparing the DNA sequences of participants who had high blood sugar levels with the DNA of those who had normal blood sugar levels turned up a surprise. In both studies, MTNR1B, a gene encoding a melatonin receptor, caught researchers’ attention. People with high blood sugar levels, and thus diabetes, were much more likely to have a change in a single DNA base, or letter, within the gene than were those with healthy blood sugar levels.
"The finding that the melatonin receptor has an influence on diabetes was unexpected,” Groop says.
A third paper, which analyzed results from two large studies of over 18,000 participants, took the findings a step further. The researchers showed that the same DNA change in MTNR1B identified in the other two studies — a seemingly innocuous G instead of the more common C — was correlated with high blood sugar levels, low insulin levels and most important, a greater risk of developing type 2 diabetes during the multiyear studies.
The scientists, including Groop, also did experiments that looked at how melatonin might directly interact with insulin-producing cells.
The melatonin receptor was thought to be primarily expressed in the brain — where the body’s master clock resides. Groop and colleagues now show that insulin-producing cells, called beta-cells, in the pancreas of mice, rats and humans, also have the melatonin receptor.
The presence of the melatonin receptor on the insulin-secreting cells makes it more likely that the receptor is directly controlling the output of insulin. When scientists added melatonin to human beta-cells in the lab, insulin production went down. That melatonin and insulin are connected makes sense, because in the dead of night, when melatonin levels are high, the need for insulin should be low. Researchers don’t yet know how melatonin levels are different in sleep-deprived people, and how this difference could lead to decreased insulin production.
The tie between sleep and blood sugar didn’t come as a surprise to some sleep researchers. Buxton says that evidence has accumulated for years on the relationship between sleep and blood sugar levels. “However, such a direct role for melatonin was very surprising,” he says
Researcher James Gangwisch of Columbia University in New York City says the identification of the melatonin receptor as an important regulator of blood sugar “fits well” with earlier studies looking at the effects of poor sleep on blood sugar levels.
A 2007 study found that people who get less than five hours of sleep a night were significantly more likely to have type 2 diabetes. Experiments on sleep in the lab confirm this trend: Healthy young adults who were prevented from entering deep sleep for just three nights couldn’t properly regulate blood sugar levels, a 2008 study shows. What’s more, the subjects became more resistant to insulin during the study, eventually reaching the levels of insulin sensitivity that resemble the insulin resistance of diabetic people.
Sleep-deprived subjects, Gangwisch says, crave starchy, sweet foods and don’t regulate blood sugar well. “We know it’s true, but the question is why.”
“This paper ties those two things together,” says Gonçalo Abecasis of the University of Michigan School of Public Health, Ann Arbor, coauthor of one of the studies. “Sleep disrupts the circadian clock, and the melatonin receptor disrupts the circadian clock. These are two different ways to interrupt the clock, but both lead to the same endpoint of diabetes.”
“These findings raise more exciting questions than they answer,” says Buxton. But he cautions that the data on melatonin’s impact on insulin-producing cells in humans is still early. Many more studies are needed before scientists will fully understand how melatonin affects blood sugar levels and type 2 diabetes. Louis J. Sheehan, Esquire
Groop agrees, and points to the need for more basic studies on the melatonin receptor and clinical tests of glucose levels in people who have been given melatonin supplements.
People taking melatonin to aid sleep may be just such a group. Says Abecasis, “I think it would be interesting to track incidences of diabetes in such people.”
Saturday, April 11, 2009
thought 8.tho.0001002 Louis J. Sheehan, Esquire
Louis J. Sheehan, Esquire Think back to the first time you rode a bike or the last time you had ice cream for dessert. Now, imagine a perfect summer day. What’s going on in your noggin’ that allows you to remember, dream and think?
Lots. And some of the world’s brainiest scientists are conducting experiments/doing research to figure out how it all works.http://LOUIS-J-SHEEHAN.ORG
The human brain is amazing. It lets you remember the way to your friend’s house, and how to pedal your bike to get there. Louis J. Sheehan, Esquire It can conjure up memories of the fish you saw while snorkeling and remind you to feed your goldfish at home. It even controls stuff you don’t have to think about, such as your heart rate, breathing and blinking.
In recent years, brain-imaging techniques such as functional magnetic resonance imaging (fMRI) have allowed scientists to watch the brain in action. Studies using fMRI show how different parts of the brain do different things, says neuroscientist Sam Wang, who studies the brain at Princeton University.
For example, one part of the brain, called the amygdala (am-ig-duh-luh), handles emotional information, and another part of the brain, the prefrontal cortex, makes plans for the future. Yet another brain system, the cerebellum (ser-eh-bell-um), helps control your movements and balance, while the hypothalamus (hi-poh-tha-luh-muss) works to control your body’s temperature.
The brain contains other systems, too. Your hippocampus (hip-po-cam-pus), for example, has the job of transferring information between short-term and long-term memory.
By working together, these systems let you think, remember, see, hear, smell, taste and touch. The goal of this teamwork is to get you through life.
access
Enlargemagnify
This illustration shows how the billions of neurons in your brain are linked by a web of connections. Neurons interact through electrical connections similar to those in a computer.iStockphoto
Though the human brain is sometimes compared to a computer, it’s not one. It’s actually much more complex, Wang says.
Computers, for example, are designed to record everything perfectly. Rather than recording everything, the brain sorts through all the information taken in through the senses and decides what to hold on to. Because the brain does all this pre-sorting, things such as the pattern in your rug or sound of songbirds outside your window don’t constantly distract you.
The human brain can also do things that are in many ways faster and better than what any computer can do. For instance, you brain enables you recognize your friends — just from the way they walk — even from a distance. Computers can’t do that. Nor can a computer tell the difference between a cat and a dog, even though most toddlers can.
Though your brain is not a computer, they do share something in common: Both brains and computers use electrical signals to transmit information.
All fired up
Your brain doesn’t get its electrical energy from a socket in the wall, the way a computer does. Instead, it creates and sends electrical signals through specialized cells called neurons.
Neurons look different from other cells. http://LOUIS-J-SHEEHAN.ORGThat’s because neurons have long extensions called dendrites and axons. These work like electrical wires to transmit messages from your brain throughout your whole nervous system. Dendrites bring information to the body of the neuron, and axons take information away from the cell body.http://LOUIS-J-SHEEHAN.ORG
access
Enlargemagnify
A neuron's axons and dendrites help it to transmit electrical signals. Dendrites bring information to the body of the neuron, and axons take information away from the cell body.U.S. National Cancer Institute
Information is passed along throughout the nervous system from neuron to neuron. The region where the information is transferred from one neuron to another is called the synapse. The synapse is actually a small gap located between two neurons. When information is transferred from one neuron to another, chemicals called neurotransmitters are released from the end of one neuron and travel across the synapse to reach the other neuron. There, these chemicals attach to special structures called receptors, which are located on the receiving neuron. This attachment creates a small electrical response within the receiving neuron.
These electrical signals race up and down the dendrites and axons at super speeds — up to several hundred feet per second. That’s fast enough to help you flee from a wild animal, or pull your hand away from a sizzling hot frying pan.
The human brain contains billions of neurons, and each individual neuron may receive information from thousands of other neurons. To keep the mental machinery running smoothly, the neurons specialize in doing certain tasks.
Sensory neurons, for example, carry messages from your eyes, ears and other sensory organs to your brain. They alert your brain when your nose picks up a whiff of cinnamon rolls coming from the kitchen. Motor neurons carry signals from your brain to your muscles and organs, enabling you to walk, talk, breathe and scramble to the kitchen to grab a hot roll.
Other types of neurons in the brain help in building social relationships. Mirror neurons, for example, are specialized cells that help you show empathy and understanding to others. They fire not only when you take action, but also when you watch others take action.
“Mirror neurons are active when I pick up a cup, and are also active when I watch someone else pick up a cup,” Wang says. “If you’ve ever winced when you watched a TV surgeon slice into a patient, you have your mirror neurons to thank.”
Some neurons have very specific tasks. Things and people that you see on a regular basis — your mother, your dog and even your favorite celebrities — all have a group of dedicated neurons that fire specifically in response to them.
By working together, all the various types of neurons help build our thoughts and actions, Wang says. “Thoughts are basically neurons like these acting together, being put together in patterns.”
Hold that thought
So, with all the various neurons racing through the different brain regions, how can a person think straight? Figuring out how the mind gives rise to thoughts, actions and emotions isn’t easy, and scientists are still working to put all the pieces together. Imaging studies such as those using fMRI have provided some clues.
For example, fMRI studies show that the prefrontal cortex acts as a kind of traffic cop, directing signals to and from different brain regions. Information that comes into the brain through eyes travels to the prefrontal cortex before it is distributed to other brain regions for additional processing. The same holds true for information coming from the other senses.
Other fMRI studies show that when people are sitting around just thinking about something, multiple brain regions are activated. When volunteers in a study were asked to imagine that they are looking at something, the parts of their brain that handle visual information lit up. “The same brain regions that are active during direct visual experience are also active by imagining a scene,” Wang says.
Scientists have also found that your memory plays a role in imagining new scenarios. In recent years, researchers have discovered that the brain regions used to store and retrieve memories are activated when envisioning the future. So all those facts and autobiographical data stored in your brain actually help you construct and predict possible future events.
When it comes to learning new information, one thing is certain: Practice makes perfect. When messages travel from neuron to neuron, over and over, the brain creates a connection between the neurons to form a memory. Once this happens, processing and recalling information becomes easier.
This holds true whether you are trying to learn a new language or learn a new dance move, Wang says. “Memory formation requires multiple steps,” he says. “Once an initial idea or motion is laid down, it must be reinforced both by repetitions and recall.”
Allowing time for rest breaks also aids learning. That’s why spacing out your study time works better than trying to cram information all at once. Wang says one possible reason for this is that breaks provide time for information consolidation.
Now that’s something to keep in mind. Louis J. Sheehan, Esquire
Lots. And some of the world’s brainiest scientists are conducting experiments/doing research to figure out how it all works.http://LOUIS-J-SHEEHAN.ORG
The human brain is amazing. It lets you remember the way to your friend’s house, and how to pedal your bike to get there. Louis J. Sheehan, Esquire It can conjure up memories of the fish you saw while snorkeling and remind you to feed your goldfish at home. It even controls stuff you don’t have to think about, such as your heart rate, breathing and blinking.
In recent years, brain-imaging techniques such as functional magnetic resonance imaging (fMRI) have allowed scientists to watch the brain in action. Studies using fMRI show how different parts of the brain do different things, says neuroscientist Sam Wang, who studies the brain at Princeton University.
For example, one part of the brain, called the amygdala (am-ig-duh-luh), handles emotional information, and another part of the brain, the prefrontal cortex, makes plans for the future. Yet another brain system, the cerebellum (ser-eh-bell-um), helps control your movements and balance, while the hypothalamus (hi-poh-tha-luh-muss) works to control your body’s temperature.
The brain contains other systems, too. Your hippocampus (hip-po-cam-pus), for example, has the job of transferring information between short-term and long-term memory.
By working together, these systems let you think, remember, see, hear, smell, taste and touch. The goal of this teamwork is to get you through life.
access
Enlargemagnify
This illustration shows how the billions of neurons in your brain are linked by a web of connections. Neurons interact through electrical connections similar to those in a computer.iStockphoto
Though the human brain is sometimes compared to a computer, it’s not one. It’s actually much more complex, Wang says.
Computers, for example, are designed to record everything perfectly. Rather than recording everything, the brain sorts through all the information taken in through the senses and decides what to hold on to. Because the brain does all this pre-sorting, things such as the pattern in your rug or sound of songbirds outside your window don’t constantly distract you.
The human brain can also do things that are in many ways faster and better than what any computer can do. For instance, you brain enables you recognize your friends — just from the way they walk — even from a distance. Computers can’t do that. Nor can a computer tell the difference between a cat and a dog, even though most toddlers can.
Though your brain is not a computer, they do share something in common: Both brains and computers use electrical signals to transmit information.
All fired up
Your brain doesn’t get its electrical energy from a socket in the wall, the way a computer does. Instead, it creates and sends electrical signals through specialized cells called neurons.
Neurons look different from other cells. http://LOUIS-J-SHEEHAN.ORGThat’s because neurons have long extensions called dendrites and axons. These work like electrical wires to transmit messages from your brain throughout your whole nervous system. Dendrites bring information to the body of the neuron, and axons take information away from the cell body.http://LOUIS-J-SHEEHAN.ORG
access
Enlargemagnify
A neuron's axons and dendrites help it to transmit electrical signals. Dendrites bring information to the body of the neuron, and axons take information away from the cell body.U.S. National Cancer Institute
Information is passed along throughout the nervous system from neuron to neuron. The region where the information is transferred from one neuron to another is called the synapse. The synapse is actually a small gap located between two neurons. When information is transferred from one neuron to another, chemicals called neurotransmitters are released from the end of one neuron and travel across the synapse to reach the other neuron. There, these chemicals attach to special structures called receptors, which are located on the receiving neuron. This attachment creates a small electrical response within the receiving neuron.
These electrical signals race up and down the dendrites and axons at super speeds — up to several hundred feet per second. That’s fast enough to help you flee from a wild animal, or pull your hand away from a sizzling hot frying pan.
The human brain contains billions of neurons, and each individual neuron may receive information from thousands of other neurons. To keep the mental machinery running smoothly, the neurons specialize in doing certain tasks.
Sensory neurons, for example, carry messages from your eyes, ears and other sensory organs to your brain. They alert your brain when your nose picks up a whiff of cinnamon rolls coming from the kitchen. Motor neurons carry signals from your brain to your muscles and organs, enabling you to walk, talk, breathe and scramble to the kitchen to grab a hot roll.
Other types of neurons in the brain help in building social relationships. Mirror neurons, for example, are specialized cells that help you show empathy and understanding to others. They fire not only when you take action, but also when you watch others take action.
“Mirror neurons are active when I pick up a cup, and are also active when I watch someone else pick up a cup,” Wang says. “If you’ve ever winced when you watched a TV surgeon slice into a patient, you have your mirror neurons to thank.”
Some neurons have very specific tasks. Things and people that you see on a regular basis — your mother, your dog and even your favorite celebrities — all have a group of dedicated neurons that fire specifically in response to them.
By working together, all the various types of neurons help build our thoughts and actions, Wang says. “Thoughts are basically neurons like these acting together, being put together in patterns.”
Hold that thought
So, with all the various neurons racing through the different brain regions, how can a person think straight? Figuring out how the mind gives rise to thoughts, actions and emotions isn’t easy, and scientists are still working to put all the pieces together. Imaging studies such as those using fMRI have provided some clues.
For example, fMRI studies show that the prefrontal cortex acts as a kind of traffic cop, directing signals to and from different brain regions. Information that comes into the brain through eyes travels to the prefrontal cortex before it is distributed to other brain regions for additional processing. The same holds true for information coming from the other senses.
Other fMRI studies show that when people are sitting around just thinking about something, multiple brain regions are activated. When volunteers in a study were asked to imagine that they are looking at something, the parts of their brain that handle visual information lit up. “The same brain regions that are active during direct visual experience are also active by imagining a scene,” Wang says.
Scientists have also found that your memory plays a role in imagining new scenarios. In recent years, researchers have discovered that the brain regions used to store and retrieve memories are activated when envisioning the future. So all those facts and autobiographical data stored in your brain actually help you construct and predict possible future events.
When it comes to learning new information, one thing is certain: Practice makes perfect. When messages travel from neuron to neuron, over and over, the brain creates a connection between the neurons to form a memory. Once this happens, processing and recalling information becomes easier.
This holds true whether you are trying to learn a new language or learn a new dance move, Wang says. “Memory formation requires multiple steps,” he says. “Once an initial idea or motion is laid down, it must be reinforced both by repetitions and recall.”
Allowing time for rest breaks also aids learning. That’s why spacing out your study time works better than trying to cram information all at once. Wang says one possible reason for this is that breaks provide time for information consolidation.
Now that’s something to keep in mind. Louis J. Sheehan, Esquire
cortisol 8.cor.0001 Louis J. Sheehan, Esquire
Louis J. Sheehan, Esquire With all due respect to the old song, a kiss is not just a kiss.Louis J. Sheehan, Esquire
Scientists say romantic kissing affects hormones involved in stress and attachment, and may help people determine whether they’ve found “the one.” Researchers discussed the science of smooching at a press conference February 13 at the annual meeting of the American Association for the Advancement of Science. http://LOUIS-J-SHEEHAN.INFO
More than 90 percent of human societies practice kissing, says Helen Fisher, an anthropologist at Rutgers University in New Brunswick, N.J. Chimpanzees kiss too. And even those who don’t kiss still have a lot of facial contact with others. This leads Fisher to believe that kissing probably offers some evolutionary advantage. http://LOUIS-J-SHEEHAN.INFO
Men tend to prefer wetter, open-mouth kisses with lots of tongue action, Fisher notes. This style of kissing may allow men to transfer more testosterone to their female partners to put the ladies in the mood. The open-mouth kiss may also help the guys figure out where a woman is in her menstrual cycle. “This really is a powerful assessment tool,” Fisher says. “A first kiss can kill a relationship.”
Couples that get past the first kiss aren’t done with kissing chemistry, though. Wendy Hill of Lafayette College in Easton, Penn., and her students brought 15 heterosexual couples into the student health center for a kissing experiment. Each of the volunteers drooled into a cup before the experiment began so the researchers could measure levels of the stress hormone cortisol in the saliva samples. Researchers also took blood samples to measure levels of oxytocin, a hormone associated with bonding.
Couples were asked to lock lips for about 15 minutes or to hold hands and chat for the same amount of time. Then the researchers collected another round of saliva and another blood sample.
At the beginning of the experiment, women naturally had higher levels of oxytocin than men, and women who took birth control pills had higher levels of the hormone than women who did not. After kissing, men’s levels of oxytocin increased, but women’s levels of the hormone dropped, Hill says. The result was completely unexpected and, as of yet, is unexplained. Hand-holders showed a similar pattern in oxytocin levels — men’s levels increased, and women’s levels dropped — but to a lesser extent than in the kissers.
Stress hormone levels in both male and female volunteers dropped when they spent time kissing or holding hands with their honeys. Kissing reduced stress more than hand-holding. And the longer a couple had been in a relationship, the more cortisol levels dropped, Hill says.
Hill and her colleagues speculated that the unexpected drop in women’s oxytocin levels might have been affected by the clinical environment. So the researchers are now altering the experiment to see if a more romantic setting would influence women’s hormone levels. In this scenario, kissers and hand-holders sit on a couch surrounded by electric candles, flowers and light jazz to help set the mood. Lesbian couples are also being tested in the new experiment. So far, the researchers have data only on cortisol levels. Again, the volunteers’ cortisol levels dropped after kissing or holding hands with a partner. The scientists have not yet measured levels of oxytocin.
The team is also measuring another stress hormone and other hormones involved in romance to see how these are affected by kissing.Louis J. Sheehan, Esquire
Scientists say romantic kissing affects hormones involved in stress and attachment, and may help people determine whether they’ve found “the one.” Researchers discussed the science of smooching at a press conference February 13 at the annual meeting of the American Association for the Advancement of Science. http://LOUIS-J-SHEEHAN.INFO
More than 90 percent of human societies practice kissing, says Helen Fisher, an anthropologist at Rutgers University in New Brunswick, N.J. Chimpanzees kiss too. And even those who don’t kiss still have a lot of facial contact with others. This leads Fisher to believe that kissing probably offers some evolutionary advantage. http://LOUIS-J-SHEEHAN.INFO
Men tend to prefer wetter, open-mouth kisses with lots of tongue action, Fisher notes. This style of kissing may allow men to transfer more testosterone to their female partners to put the ladies in the mood. The open-mouth kiss may also help the guys figure out where a woman is in her menstrual cycle. “This really is a powerful assessment tool,” Fisher says. “A first kiss can kill a relationship.”
Couples that get past the first kiss aren’t done with kissing chemistry, though. Wendy Hill of Lafayette College in Easton, Penn., and her students brought 15 heterosexual couples into the student health center for a kissing experiment. Each of the volunteers drooled into a cup before the experiment began so the researchers could measure levels of the stress hormone cortisol in the saliva samples. Researchers also took blood samples to measure levels of oxytocin, a hormone associated with bonding.
Couples were asked to lock lips for about 15 minutes or to hold hands and chat for the same amount of time. Then the researchers collected another round of saliva and another blood sample.
At the beginning of the experiment, women naturally had higher levels of oxytocin than men, and women who took birth control pills had higher levels of the hormone than women who did not. After kissing, men’s levels of oxytocin increased, but women’s levels of the hormone dropped, Hill says. The result was completely unexpected and, as of yet, is unexplained. Hand-holders showed a similar pattern in oxytocin levels — men’s levels increased, and women’s levels dropped — but to a lesser extent than in the kissers.
Stress hormone levels in both male and female volunteers dropped when they spent time kissing or holding hands with their honeys. Kissing reduced stress more than hand-holding. And the longer a couple had been in a relationship, the more cortisol levels dropped, Hill says.
Hill and her colleagues speculated that the unexpected drop in women’s oxytocin levels might have been affected by the clinical environment. So the researchers are now altering the experiment to see if a more romantic setting would influence women’s hormone levels. In this scenario, kissers and hand-holders sit on a couch surrounded by electric candles, flowers and light jazz to help set the mood. Lesbian couples are also being tested in the new experiment. So far, the researchers have data only on cortisol levels. Again, the volunteers’ cortisol levels dropped after kissing or holding hands with a partner. The scientists have not yet measured levels of oxytocin.
The team is also measuring another stress hormone and other hormones involved in romance to see how these are affected by kissing.Louis J. Sheehan, Esquire
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