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Mind: When Parents Are Too Toxic to Tolerate
By RICHARD A. FRIEDMAN, M.D., October 20, 2009
You can divorce an abusive spouse. You can call it quits if your lover mistreats you. But what can you do if the source of your misery is your own parent?
Granted, no parent is perfect. And whining about parental failure, real or not, is practically an American pastime that keeps the therapeutic community dutifully employed.
But just as there are ordinary good-enough parents who mysteriously produce a difficult child, there are some decent people who have the misfortune of having a truly toxic parent.
A patient of mine, a lovely woman in her 60s whom I treated for depression, recently asked my advice about how to deal with her aging mother.
“She’s always been extremely abusive of me and my siblings,” she said, as I recall. “Once, on my birthday, she left me a message wishing that I get a disease. Can you believe it?”
Over the years, she had tried to have a relationship with her mother, but the encounters were always painful and upsetting; her mother remained harshly critical and demeaning.
Whether her mother was mentally ill, just plain mean or both was unclear, but there was no question that my patient had decided long ago that the only way to deal with her mother was to avoid her at all costs.
Now that her mother was approaching death, she was torn about yet another effort at reconciliation. “I feel I should try,” my patient told me, “but I know she’ll be awful to me.”
Should she visit and perhaps forgive her mother, or protect herself and live with a sense of guilt, however unjustified? Tough call, and clearly not mine to make.
But it did make me wonder about how therapists deal with adult patients who have toxic parents.
The topic gets little, if any, attention in standard textbooks or in the psychiatric literature, perhaps reflecting the common and mistaken notion that adults, unlike children and the elderly, are not vulnerable to such emotional abuse.
All too often, I think, therapists have a bias to salvage relationships, even those that might be harmful to a patient. Instead, it is crucial to be open-minded and to consider whether maintaining the relationship is really healthy and desirable.
Likewise, the assumption that parents are predisposed to love their children unconditionally and protect them from harm is not universally true. I remember one patient, a man in his mid-20s, who came to me for depression and rock-bottom self-esteem.
It didn’t take long to find out why. He had recently come out as gay to his devoutly religious parents, who responded by disowning him. It gets worse: at a subsequent family dinner, his father took him aside and told him it would have been better if he, rather than his younger brother, had died in a car accident several years earlier.
Though terribly hurt and angry, this young man still hoped he could get his parents to accept his sexuality and asked me to meet with the three of them.
The session did not go well. The parents insisted that his “lifestyle” was a grave sin, incompatible with their deeply held religious beliefs. When I tried to explain that the scientific consensus was that he had no more choice about his sexual orientation than the color of his eyes, they were unmoved. They simply could not accept him as he was.
I was stunned by their implacable hostility and convinced that they were a psychological menace to my patient. As such, I had to do something I have never contemplated before in treatment.
At the next session I suggested that for his psychological well-being he might consider, at least for now, forgoing a relationship with his parents.
I felt this was a drastic measure, akin to amputating a gangrenous limb to save a patient’s life. My patient could not escape all the negative feelings and thoughts about himself that he had internalized from his parents. But at least I could protect him from even more psychological harm.
Easier said than done. He accepted my suggestion with sad resignation, though he did make a few efforts to contact them over the next year. They never responded.
Of course, relationships are rarely all good or bad; even the most abusive parents can sometimes be loving, which is why severing a bond should be a tough, and rare, decision.
Dr. Judith Lewis Herman, a trauma expert who is a clinical professor of psychiatry at Harvard Medical School, said she tried to empower patients to take action to protect themselves without giving direct advice.
“Sometimes we consider a paradoxical intervention and say to a patient, ‘I really admire your loyalty to your parents — even at the expense of failing to protect yourself in any way from harm,’ ” Dr. Herman told me in an interview.
The hope is that patients come to see the psychological cost of a harmful relationship and act to change it.
Eventually, my patient made a full recovery from his depression and started dating, though his parents’ absence in his life was never far from his thoughts.
No wonder. Research on early attachment, both in humans and in nonhuman primates, shows that we are hard-wired for bonding — even to those who aren’t very nice to us.
We also know that although prolonged childhood trauma can be toxic to the brain, adults retain the ability later in life to rewire their brains by new experience, including therapy and psychotropic medication.
For example, prolonged stress can kill cells in the hippocampus, a brain area critical for memory. The good news is that adults are able to grow new neurons in this area in the course of normal development. Also, antidepressants encourage the development of new cells in the hippocampus.
It is no stretch, then, to say that having a toxic parent may be harmful to a child’s brain, let alone his feelings. But that damage need not be written in stone.
Of course, we cannot undo history with therapy. But we can help mend brains and minds by removing or reducing stress.
Sometimes, as drastic as it sounds, that means letting go of a toxic parent.
Dr. Richard A. Friedman is a professor of psychiatry at Weill Cornell Medical College.
Remarkable Creatures: For Fish in Coral Reefs, It’s Useful to Be Smart
By SEAN B. CARROLL, October 20, 2009
I have long suspected that fish are smarter than we give them credit for.
As a child, I had an aquarium with several pet goldfish. They certainly knew it was feeding time when my hand appeared over their tank, and they excitedly awaited their delicious fish flakes.
They also exhibited a darker, disturbing behavior. Evidently, a safe life with abundant food was not fulfilling. From time to time, either sheer ennui or the long gray Toledo winter got to one of the fish and it ended its torment with a leap to my bedroom floor.
Maybe my anthropomorphizing is a bit over the top. But, really, just how smart are fish? Can they learn?
A 10-gallon tank with a plastic sunken pirate ship is certainly not the most stimulating habitat. But in the colorful, diverse and dangerous world of coral reefs, fish must be able to recognize not only food, but also to discriminate friends from foes, and mates from rivals, and to take the best action. In such a complex and dynamic environment, it would pay to be flexible and able to learn.
A series of studies has recently revealed that reef fish are surprisingly adaptable. Freshly caught wild fish quickly learn new tasks and can learn to discriminate among colors, patterns and shapes, including those they have never encountered. These studies suggest that learning and interpreting new stimuli play important roles in the lives of reef fish.
To test the ability of fish to learn to discriminate shapes, a research team led by Ulrike E. Siebeck at the University of Queensland in Brisbane, Australia, trained damselfish to feed from a feeding tube to which they attached a variety of visual stimuli. The latter included a three-dimensional latex disc, a two-dimensional blue disc painted on a plastic board, or black circles or propeller patterns on white boards. The fish were rewarded with food when they repeatedly tapped the stimulus — not the tube — with their snout or mouth.
The fish rapidly learned this task. The researchers then presented the fish with the original stimulus and one alternative distracting shape — bars versus discs, squares versus discs, or circles versus propellers, and the fish had to nose the shape they had been trained to tap in order to receive a reward. The fish tapped the correct shape about 70 percent of the time in the first trial; this improved to 80 percent to 90 percent in subsequent trials.
Remarkably, the fish also learned when the food reward was delayed and delivered far from the stimulus. The damselfish exhibited what is called anticipatory behavior, in that they would tap the image and then swim quickly to the other end of their tank in anticipation of their food reward. This response is much like Pavlov’s dogs who learned to anticipate food at the sound of a bell.
In another set of experiments, Dr. Siebeck trained damselfish on different color stimuli. She selected blue and yellow because these are highly contrasting colors that are found on many reef fish. After the fish quickly learned to repeatedly tap colored latex targets to gain a food reward, they were presented with a choice between the training target and the alternative color target. The fish were even better at color discrimination, tapping the correct target more than 90 percent of the time.
Perhaps it is less surprising that the fish learned to discriminate colors. After all, they live in a colorful environment. But the question of why reef fish are typically so colorful has challenged biologists for a very long time. It seems obvious that bright color patterns would be effective communication signals in the shallow, well-lighted water around coral reefs. But in that fish-eat-fish world, bright colors would also make fish conspicuous to predators. So how are these advantages and disadvantages balanced?
It turns out that some brightly colored fish make a living by providing a valuable service to what may otherwise be their predators: they clean them. In fact, cleaner fish like the cleaner wrasse form an important part of coral reef communities. They establish small territories as “cleaning stations,” which are visited by all sorts of “client” fish that have their parasites removed.
The cleaners’ work ethic is astounding. Alexandra Grutter of the University of Queensland found that individual cleaner wrasse inspected as many as 2,300 fish and consumed up to 1,200 parasites a day, which amounted to about 7 percent of their body weight. Furthermore, Dr. Grutter found that fish on reefs without cleaner fish had about five times the number of parasites compared with fish on reefs with cleaners.
It would seem, then, that it would benefit potential clients to visit cleaning stations, and for carnivorous clients not to eat their cleaners. So, how do clients find and recognize cleaners? It appears that certain body colors, particularly blue and yellow, signal cleaning behavior to potential clients.
To investigate the role of color in the cleaner-client relationship, another research team from the University of Queensland — including Dr. Grutter, Karen Cheney, Simon Blomberg and N. Justin Marshall — first looked at the distribution of body colors among cleaner and noncleaner fish from the same families. They found cleaner fish were significantly more likely to have a blue or yellow coloration.
Furthermore, they showed that these colors were the most contrasting ones on coral backgrounds to clients like barracuda or surgeonfish and that the contrast was enhanced against black backgrounds. In fact, all species they examined that make their living solely from cleaning also had a contrast-enhancing black lateral body stripe adjacent to these colors, whereas none of the 31 noncleaner species were so marked.
To test whether potential clients paid attention to these color schemes, the researchers painted models with various permutations of cleaner colors in which they omitted the blue pattern or replaced it with red, or altered the pattern, orientation and width of body stripes. They then placed these models around reefs fringing Lizard Island, at the northern end of the Great Barrier Reef, and observed the frequency with which client fish visited the models. They found that the model that most closely represented the natural blue-streak cleaner wrasse pattern was visited more frequently than any other model color scheme.
In a similar study performed off Sulawesi, Indonesia, the length of the model’s black body stripe also affected the frequency of client visits. On coral reefs, it pays to advertise, even when potential enemies abound.
With their attention to colors, patterns and shapes and their ability to learn about new forms, one wonders how much these creatures can learn and what limitations they might have. They couldn’t read Dr. Seuss, of course, but they might enjoy looking at the pictures.
Sean B. Carroll, a molecular biologist and geneticist, is the author of “Remarkable Creatures: Epic Adventures in the Search for the Origin of Species,” which has been nominated for a National Book Award.
Researchers Create Artificial Memories in the Brain of a Fruitfly
By NICHOLAS WADE, October 20, 2009
As part of a project to understand how the brain learns, biologists have written memories into the cells of a fruitfly’s brain, making it think it had a terrible experience.
The memory trace was written by shining light into the fly’s brain and activating a special class of cells involved in learning how to avoid an electric shock.
The goal of the research is not to give flies nightmares but rather to understand how learning in general works, from flies to people. “In the case of the fly, where we have a numerically rather simple nervous system that does something rather complex, I think we have a chance to break open the black box and understand it,” said Gero Miesenböck of the University of Oxford, leader of the team that has developed the new technique.
Psychologists study learning by running rats through mazes, but biologists want to learn the actual mechanics of how a memory trace is laid down in a nerve cell or neuron. So they need an organism whose genes can be easily manipulated.
In the early days of molecular biology, when others were working on DNA, the biologist Seymour Benzer decided to dissect behavior by studying the fruitfly. His student Chip Quinn discovered in the early 1970s that fruitflies, surprisingly, could learn. If exposed to a chemical odor and at the same time given an electric jolt big enough to kill a person, the fruitflies associated the two and would in the future avoid the odor.
Of the two chemicals that Mr. Quinn picked, one smelled like licorice and the other “a lot like tennis shoes in July,” according to Jonathan Weiner, author of “Time, Love, Memory,” an entrancing history of Benzer’s work. Biologists ever since have used the same system to train fruitflies. With the aid of the licorice and tennis shoe odors, Dr. Miesenböck’s team has now managed to peer deep inside the black box of the fly’s learning system.
His goal is to dissect the neural circuitry through which the fly associates a particular odor with electric shocks, so he began by looking at a class of neurons that generate the chemical messenger known as dopamine.
In the human brain, dopamine signals pleasure and reward but in flies it does the exact opposite: it is the messenger of fear and aversion. The fly has some 200 dopamine-producing neurons, and these must be involved to help the fly associate fragrance of tennis shoe with a really bad scene.
Dr. Miesenböck’s team was able to distinguish, by their genetics, different classes of the dopamine-making neurons. By tagging each class of neurons with a gene that makes a fluorescent protein, they could make the dopamine neurons light up and they could trace their circuitry. Only one class, consisting of just 12 neurons, made the right connections in the fly’s brain to function in learning shock avoidance, they report in the current issue of Cell.
These 12 neurons, which were receiving news of electric shocks and generating dopamine, converge on another group of neurons called Kenyon cells to which they seem to be passing on news of the shock, via dopamine. Since the Kenyon cells also receive messages about odors from receptors on the fly’s antennae, they seemed to be the place where the memory of the experience was laid down.
To test their understanding of the system, Dr. Miesenböck and his colleagues activated the Kenyon cells themselves instead of having the fly experience an electric shock. They genetically engineered a strain of flies whose Kenyon cells would respond to flashes of light. The light releases an injected chemical to which the cells have been made sensitive.
Instead of exposing the flies to an odor and an electric shock, the researchers applied the odor and a flash of light to activate the Kenyon cells. The light was just as good as the shock: by activating the Kenyon cells at the same time as the aroma was sensed, it wrote a message in the fly’s brain that eau de tennis shoe was something to eschew.
With this handle on the learning mechanism, Dr. Miesenböck hopes to trace the rest of the circuitry. He thinks the Kenyon cells may project onto others that control the fly’s movement. So when the fly senses the tennis shoe odor, the Kenyon cells will all send their messages to the motion cells, acting like voters in a ballot to influence the fly’s movement. The stronger the aversive connotation of the odor, the greater the number of Kenyon cells voting to leave in a hurry.
The learning system must also have some method for estimating how well the lesson has been learned, Dr. Miesenböck said in an interview. Once the association between odor and shock has been established, the fly’s model of the world is 100 percent correct and there is no need for further changes to the memory trace; it is not clear, however, how this is accomplished.
When the entire learning circuitry is mapped, will the fly, and other creatures with learning neurons, seem just like biological machines? “If one really sees what interacts with the gears and how the neural clockwork runs, that would be the level of explanation that satisfies me,” Dr. Miesenböck said.
Ralph Greenspan, an expert on fruitfly behavior at the Neurosciences Institute in San Diego, said, “This paper begins to pin down the detailed circuitry that underlies this associative condition pathway in the fruitfly.”
Asked if the technique might help to trace the whole nervous pathway from sensing the odor to flying away, Dr. Greenspan replied, “It would be a miracle at this point because the notion of where this process produces a motor output is as undefined as it could be,” meaning that the neural circuits that drive the fly’s motion are still unknown. The black box of the fruitfly’s brain still holds many dark corners.
Really? The Claim: Garlic Can Be Helpful in Warding Off a Cold
By ANAHAD O’CONNOR, October 20, 2009
THE FACTS For centuries, garlic has been extolled not just for its versatility in the kitchen but also for its medicinal powers.
Whatever the reason, studies seem to support an effect. In one double-blind study, published in 2001, British scientists followed 146 healthy adults over 12 weeks from November to February. Those who had been randomly selected to receive a daily garlic supplement came down with 24 colds during the study period, compared with 65 colds in the placebo group. The garlic group experienced 111 days of sickness, versus 366 for those given a placebo. They also recovered faster.
Besides the odor, studies have found minimal side effects, like nausea and rash.
One possible explanation for such benefits is that a compound called allicin, the main biologically active component of garlic, blocks enzymes that play a role in bacterial and viral infections. Or perhaps people who consume enough garlic simply repel others, and thus steer clear of their germs.
In a report this year in The Cochrane Database of Systematic Reviews, scientists who examined the science argued that while the evidence was good for garlic’s preventive powers, more studies were needed.
They pointed out that it was still unclear whether taking garlic at the very start of a cold, as opposed to weeks in advance, would make any difference.
THE BOTTOM LINE Research is limited, but it suggests that garlic may indeed help ward off colds.
By RICHARD A. FRIEDMAN, M.D., October 20, 2009
You can divorce an abusive spouse. You can call it quits if your lover mistreats you. But what can you do if the source of your misery is your own parent?
Granted, no parent is perfect. And whining about parental failure, real or not, is practically an American pastime that keeps the therapeutic community dutifully employed.
But just as there are ordinary good-enough parents who mysteriously produce a difficult child, there are some decent people who have the misfortune of having a truly toxic parent.
A patient of mine, a lovely woman in her 60s whom I treated for depression, recently asked my advice about how to deal with her aging mother.
“She’s always been extremely abusive of me and my siblings,” she said, as I recall. “Once, on my birthday, she left me a message wishing that I get a disease. Can you believe it?”
Over the years, she had tried to have a relationship with her mother, but the encounters were always painful and upsetting; her mother remained harshly critical and demeaning.
Whether her mother was mentally ill, just plain mean or both was unclear, but there was no question that my patient had decided long ago that the only way to deal with her mother was to avoid her at all costs.
Now that her mother was approaching death, she was torn about yet another effort at reconciliation. “I feel I should try,” my patient told me, “but I know she’ll be awful to me.”
Should she visit and perhaps forgive her mother, or protect herself and live with a sense of guilt, however unjustified? Tough call, and clearly not mine to make.
But it did make me wonder about how therapists deal with adult patients who have toxic parents.
The topic gets little, if any, attention in standard textbooks or in the psychiatric literature, perhaps reflecting the common and mistaken notion that adults, unlike children and the elderly, are not vulnerable to such emotional abuse.
All too often, I think, therapists have a bias to salvage relationships, even those that might be harmful to a patient. Instead, it is crucial to be open-minded and to consider whether maintaining the relationship is really healthy and desirable.
Likewise, the assumption that parents are predisposed to love their children unconditionally and protect them from harm is not universally true. I remember one patient, a man in his mid-20s, who came to me for depression and rock-bottom self-esteem.
It didn’t take long to find out why. He had recently come out as gay to his devoutly religious parents, who responded by disowning him. It gets worse: at a subsequent family dinner, his father took him aside and told him it would have been better if he, rather than his younger brother, had died in a car accident several years earlier.
Though terribly hurt and angry, this young man still hoped he could get his parents to accept his sexuality and asked me to meet with the three of them.
The session did not go well. The parents insisted that his “lifestyle” was a grave sin, incompatible with their deeply held religious beliefs. When I tried to explain that the scientific consensus was that he had no more choice about his sexual orientation than the color of his eyes, they were unmoved. They simply could not accept him as he was.
I was stunned by their implacable hostility and convinced that they were a psychological menace to my patient. As such, I had to do something I have never contemplated before in treatment.
At the next session I suggested that for his psychological well-being he might consider, at least for now, forgoing a relationship with his parents.
I felt this was a drastic measure, akin to amputating a gangrenous limb to save a patient’s life. My patient could not escape all the negative feelings and thoughts about himself that he had internalized from his parents. But at least I could protect him from even more psychological harm.
Easier said than done. He accepted my suggestion with sad resignation, though he did make a few efforts to contact them over the next year. They never responded.
Of course, relationships are rarely all good or bad; even the most abusive parents can sometimes be loving, which is why severing a bond should be a tough, and rare, decision.
Dr. Judith Lewis Herman, a trauma expert who is a clinical professor of psychiatry at Harvard Medical School, said she tried to empower patients to take action to protect themselves without giving direct advice.
“Sometimes we consider a paradoxical intervention and say to a patient, ‘I really admire your loyalty to your parents — even at the expense of failing to protect yourself in any way from harm,’ ” Dr. Herman told me in an interview.
The hope is that patients come to see the psychological cost of a harmful relationship and act to change it.
Eventually, my patient made a full recovery from his depression and started dating, though his parents’ absence in his life was never far from his thoughts.
No wonder. Research on early attachment, both in humans and in nonhuman primates, shows that we are hard-wired for bonding — even to those who aren’t very nice to us.
We also know that although prolonged childhood trauma can be toxic to the brain, adults retain the ability later in life to rewire their brains by new experience, including therapy and psychotropic medication.
For example, prolonged stress can kill cells in the hippocampus, a brain area critical for memory. The good news is that adults are able to grow new neurons in this area in the course of normal development. Also, antidepressants encourage the development of new cells in the hippocampus.
It is no stretch, then, to say that having a toxic parent may be harmful to a child’s brain, let alone his feelings. But that damage need not be written in stone.
Of course, we cannot undo history with therapy. But we can help mend brains and minds by removing or reducing stress.
Sometimes, as drastic as it sounds, that means letting go of a toxic parent.
Dr. Richard A. Friedman is a professor of psychiatry at Weill Cornell Medical College.
Remarkable Creatures: For Fish in Coral Reefs, It’s Useful to Be Smart
By SEAN B. CARROLL, October 20, 2009
I have long suspected that fish are smarter than we give them credit for.
As a child, I had an aquarium with several pet goldfish. They certainly knew it was feeding time when my hand appeared over their tank, and they excitedly awaited their delicious fish flakes.
They also exhibited a darker, disturbing behavior. Evidently, a safe life with abundant food was not fulfilling. From time to time, either sheer ennui or the long gray Toledo winter got to one of the fish and it ended its torment with a leap to my bedroom floor.
Maybe my anthropomorphizing is a bit over the top. But, really, just how smart are fish? Can they learn?
A 10-gallon tank with a plastic sunken pirate ship is certainly not the most stimulating habitat. But in the colorful, diverse and dangerous world of coral reefs, fish must be able to recognize not only food, but also to discriminate friends from foes, and mates from rivals, and to take the best action. In such a complex and dynamic environment, it would pay to be flexible and able to learn.
A series of studies has recently revealed that reef fish are surprisingly adaptable. Freshly caught wild fish quickly learn new tasks and can learn to discriminate among colors, patterns and shapes, including those they have never encountered. These studies suggest that learning and interpreting new stimuli play important roles in the lives of reef fish.
To test the ability of fish to learn to discriminate shapes, a research team led by Ulrike E. Siebeck at the University of Queensland in Brisbane, Australia, trained damselfish to feed from a feeding tube to which they attached a variety of visual stimuli. The latter included a three-dimensional latex disc, a two-dimensional blue disc painted on a plastic board, or black circles or propeller patterns on white boards. The fish were rewarded with food when they repeatedly tapped the stimulus — not the tube — with their snout or mouth.
The fish rapidly learned this task. The researchers then presented the fish with the original stimulus and one alternative distracting shape — bars versus discs, squares versus discs, or circles versus propellers, and the fish had to nose the shape they had been trained to tap in order to receive a reward. The fish tapped the correct shape about 70 percent of the time in the first trial; this improved to 80 percent to 90 percent in subsequent trials.
Remarkably, the fish also learned when the food reward was delayed and delivered far from the stimulus. The damselfish exhibited what is called anticipatory behavior, in that they would tap the image and then swim quickly to the other end of their tank in anticipation of their food reward. This response is much like Pavlov’s dogs who learned to anticipate food at the sound of a bell.
In another set of experiments, Dr. Siebeck trained damselfish on different color stimuli. She selected blue and yellow because these are highly contrasting colors that are found on many reef fish. After the fish quickly learned to repeatedly tap colored latex targets to gain a food reward, they were presented with a choice between the training target and the alternative color target. The fish were even better at color discrimination, tapping the correct target more than 90 percent of the time.
Perhaps it is less surprising that the fish learned to discriminate colors. After all, they live in a colorful environment. But the question of why reef fish are typically so colorful has challenged biologists for a very long time. It seems obvious that bright color patterns would be effective communication signals in the shallow, well-lighted water around coral reefs. But in that fish-eat-fish world, bright colors would also make fish conspicuous to predators. So how are these advantages and disadvantages balanced?
It turns out that some brightly colored fish make a living by providing a valuable service to what may otherwise be their predators: they clean them. In fact, cleaner fish like the cleaner wrasse form an important part of coral reef communities. They establish small territories as “cleaning stations,” which are visited by all sorts of “client” fish that have their parasites removed.
The cleaners’ work ethic is astounding. Alexandra Grutter of the University of Queensland found that individual cleaner wrasse inspected as many as 2,300 fish and consumed up to 1,200 parasites a day, which amounted to about 7 percent of their body weight. Furthermore, Dr. Grutter found that fish on reefs without cleaner fish had about five times the number of parasites compared with fish on reefs with cleaners.
It would seem, then, that it would benefit potential clients to visit cleaning stations, and for carnivorous clients not to eat their cleaners. So, how do clients find and recognize cleaners? It appears that certain body colors, particularly blue and yellow, signal cleaning behavior to potential clients.
To investigate the role of color in the cleaner-client relationship, another research team from the University of Queensland — including Dr. Grutter, Karen Cheney, Simon Blomberg and N. Justin Marshall — first looked at the distribution of body colors among cleaner and noncleaner fish from the same families. They found cleaner fish were significantly more likely to have a blue or yellow coloration.
Furthermore, they showed that these colors were the most contrasting ones on coral backgrounds to clients like barracuda or surgeonfish and that the contrast was enhanced against black backgrounds. In fact, all species they examined that make their living solely from cleaning also had a contrast-enhancing black lateral body stripe adjacent to these colors, whereas none of the 31 noncleaner species were so marked.
To test whether potential clients paid attention to these color schemes, the researchers painted models with various permutations of cleaner colors in which they omitted the blue pattern or replaced it with red, or altered the pattern, orientation and width of body stripes. They then placed these models around reefs fringing Lizard Island, at the northern end of the Great Barrier Reef, and observed the frequency with which client fish visited the models. They found that the model that most closely represented the natural blue-streak cleaner wrasse pattern was visited more frequently than any other model color scheme.
In a similar study performed off Sulawesi, Indonesia, the length of the model’s black body stripe also affected the frequency of client visits. On coral reefs, it pays to advertise, even when potential enemies abound.
With their attention to colors, patterns and shapes and their ability to learn about new forms, one wonders how much these creatures can learn and what limitations they might have. They couldn’t read Dr. Seuss, of course, but they might enjoy looking at the pictures.
Sean B. Carroll, a molecular biologist and geneticist, is the author of “Remarkable Creatures: Epic Adventures in the Search for the Origin of Species,” which has been nominated for a National Book Award.
Researchers Create Artificial Memories in the Brain of a Fruitfly
By NICHOLAS WADE, October 20, 2009
As part of a project to understand how the brain learns, biologists have written memories into the cells of a fruitfly’s brain, making it think it had a terrible experience.
The memory trace was written by shining light into the fly’s brain and activating a special class of cells involved in learning how to avoid an electric shock.
The goal of the research is not to give flies nightmares but rather to understand how learning in general works, from flies to people. “In the case of the fly, where we have a numerically rather simple nervous system that does something rather complex, I think we have a chance to break open the black box and understand it,” said Gero Miesenböck of the University of Oxford, leader of the team that has developed the new technique.
Psychologists study learning by running rats through mazes, but biologists want to learn the actual mechanics of how a memory trace is laid down in a nerve cell or neuron. So they need an organism whose genes can be easily manipulated.
In the early days of molecular biology, when others were working on DNA, the biologist Seymour Benzer decided to dissect behavior by studying the fruitfly. His student Chip Quinn discovered in the early 1970s that fruitflies, surprisingly, could learn. If exposed to a chemical odor and at the same time given an electric jolt big enough to kill a person, the fruitflies associated the two and would in the future avoid the odor.
Of the two chemicals that Mr. Quinn picked, one smelled like licorice and the other “a lot like tennis shoes in July,” according to Jonathan Weiner, author of “Time, Love, Memory,” an entrancing history of Benzer’s work. Biologists ever since have used the same system to train fruitflies. With the aid of the licorice and tennis shoe odors, Dr. Miesenböck’s team has now managed to peer deep inside the black box of the fly’s learning system.
His goal is to dissect the neural circuitry through which the fly associates a particular odor with electric shocks, so he began by looking at a class of neurons that generate the chemical messenger known as dopamine.
In the human brain, dopamine signals pleasure and reward but in flies it does the exact opposite: it is the messenger of fear and aversion. The fly has some 200 dopamine-producing neurons, and these must be involved to help the fly associate fragrance of tennis shoe with a really bad scene.
Dr. Miesenböck’s team was able to distinguish, by their genetics, different classes of the dopamine-making neurons. By tagging each class of neurons with a gene that makes a fluorescent protein, they could make the dopamine neurons light up and they could trace their circuitry. Only one class, consisting of just 12 neurons, made the right connections in the fly’s brain to function in learning shock avoidance, they report in the current issue of Cell.
These 12 neurons, which were receiving news of electric shocks and generating dopamine, converge on another group of neurons called Kenyon cells to which they seem to be passing on news of the shock, via dopamine. Since the Kenyon cells also receive messages about odors from receptors on the fly’s antennae, they seemed to be the place where the memory of the experience was laid down.
To test their understanding of the system, Dr. Miesenböck and his colleagues activated the Kenyon cells themselves instead of having the fly experience an electric shock. They genetically engineered a strain of flies whose Kenyon cells would respond to flashes of light. The light releases an injected chemical to which the cells have been made sensitive.
Instead of exposing the flies to an odor and an electric shock, the researchers applied the odor and a flash of light to activate the Kenyon cells. The light was just as good as the shock: by activating the Kenyon cells at the same time as the aroma was sensed, it wrote a message in the fly’s brain that eau de tennis shoe was something to eschew.
With this handle on the learning mechanism, Dr. Miesenböck hopes to trace the rest of the circuitry. He thinks the Kenyon cells may project onto others that control the fly’s movement. So when the fly senses the tennis shoe odor, the Kenyon cells will all send their messages to the motion cells, acting like voters in a ballot to influence the fly’s movement. The stronger the aversive connotation of the odor, the greater the number of Kenyon cells voting to leave in a hurry.
The learning system must also have some method for estimating how well the lesson has been learned, Dr. Miesenböck said in an interview. Once the association between odor and shock has been established, the fly’s model of the world is 100 percent correct and there is no need for further changes to the memory trace; it is not clear, however, how this is accomplished.
When the entire learning circuitry is mapped, will the fly, and other creatures with learning neurons, seem just like biological machines? “If one really sees what interacts with the gears and how the neural clockwork runs, that would be the level of explanation that satisfies me,” Dr. Miesenböck said.
Ralph Greenspan, an expert on fruitfly behavior at the Neurosciences Institute in San Diego, said, “This paper begins to pin down the detailed circuitry that underlies this associative condition pathway in the fruitfly.”
Asked if the technique might help to trace the whole nervous pathway from sensing the odor to flying away, Dr. Greenspan replied, “It would be a miracle at this point because the notion of where this process produces a motor output is as undefined as it could be,” meaning that the neural circuits that drive the fly’s motion are still unknown. The black box of the fruitfly’s brain still holds many dark corners.
Really? The Claim: Garlic Can Be Helpful in Warding Off a Cold
By ANAHAD O’CONNOR, October 20, 2009
THE FACTS For centuries, garlic has been extolled not just for its versatility in the kitchen but also for its medicinal powers.
Whatever the reason, studies seem to support an effect. In one double-blind study, published in 2001, British scientists followed 146 healthy adults over 12 weeks from November to February. Those who had been randomly selected to receive a daily garlic supplement came down with 24 colds during the study period, compared with 65 colds in the placebo group. The garlic group experienced 111 days of sickness, versus 366 for those given a placebo. They also recovered faster.
Besides the odor, studies have found minimal side effects, like nausea and rash.
One possible explanation for such benefits is that a compound called allicin, the main biologically active component of garlic, blocks enzymes that play a role in bacterial and viral infections. Or perhaps people who consume enough garlic simply repel others, and thus steer clear of their germs.
In a report this year in The Cochrane Database of Systematic Reviews, scientists who examined the science argued that while the evidence was good for garlic’s preventive powers, more studies were needed.
They pointed out that it was still unclear whether taking garlic at the very start of a cold, as opposed to weeks in advance, would make any difference.
THE BOTTOM LINE Research is limited, but it suggests that garlic may indeed help ward off colds.
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Date: 2009-10-20 05:53 pm (UTC)no subject
Date: 2009-10-21 03:46 pm (UTC)no subject
Date: 2009-10-20 06:20 pm (UTC)no subject
Date: 2009-10-21 03:46 pm (UTC)no subject
Date: 2009-10-21 10:20 pm (UTC)I wish more people I care about who have abusive parents would have been given the advice or taken that action earlier (straight and gay, btw).
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Date: 2009-10-21 03:39 am (UTC)And I always eat raw garlic when I feel a cold coming on. I just chop up a clove into manageable pieces and swallow them in the morning for a few days until my symptoms go away. Always wondered if really worked or it was just in my head, but it seems to fight the colds off so I keep doing it. Glad to see there is some science Tuesday behind it. :)
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Date: 2009-10-21 03:48 pm (UTC)