Geoffrey Carr notes: "...the demographic shift that all populations (so far) have undergone as they have enriched themselves. For the negative exponent is starting to show up, and its cause is not lack of space or resources, nor yet is it conflict or disease (even AIDS, malaria and tuberculosis make only a small difference in global terms). Instead, it is the thing that the doomsters feared most after population growth — economic growth."
"Perhaps the answer lies in the old idea of r and K selection. Indeed, the terms r and K come from variables in two-term logistic equation that describes real population dynamics. K-selected species, people may remember from their college ecology classes, have few offspring but nurture them lovingly. Those that are r-selected have lots, but display a Devil-take-the-hindmost attitude to their issue's survival. The crucial point is that K-selected species live in safe, predictable environments, while r-selected ones live in unsafe, unpredictable ones. If the individuals of a species were able to shift opportunistically between r and K strategies in response to shifts in the environment, then something like the demographic transition in response to wealth might be the result."
Wednesday, February 14, 2007
Tuesday, February 13, 2007
The end of ISMs
Marc D. Hauser:
"Racism, Sexism, Species-ism, Age-ism, Elitism, Fundamentalism, Atheism. These –isms, and others, have fueled hatred, inspired war, justified torture, divided countries, prevented education, increased disparities in wealth, and destroyed civilizations...there is a single underlying cause: a brain that evolved an unconscious capacity to seek differences between self and other, and once identified, seek to demote the other in the service of selfish gains... The good news is that science is uncovering some of the details of this destructive capacity, and may hold the key to an applied solution. My optimism: if we play our cards correctly, we may see the day when our instinctive prejudice toward the other will dissolve, gaining greater respect for differences, expanding our moral circle."
Among the items Hauser suggests in a possible playbook:
"Recognize the universality of our moral intuitions...Remove the doctrinal rules and our intuitive moral psychology propels us to decide what is morally right or wrong based on general principles concerning the welfare of others and our own virtues. If the Protestant and Catholic Irish can see past their religious beliefs, empathize with the other, recognize their shared underlying humanity and settle into peaceful co-existence, why not other warring factions?"
"Be vigilant of disgust...Although disgust was born out of an adaptive response to potential disease vectors, things that are normally inside but are now outside such as vomit, blood, and feces, it is a mischievous emotion, sneaking into other problems, alighting, wreaking havoc on group structure, and then spreading. Throughout the history of warfare, every warring group has tagged their enemy with qualities that are reminiscent of disease, filth, and parasites."
"Racism, Sexism, Species-ism, Age-ism, Elitism, Fundamentalism, Atheism. These –isms, and others, have fueled hatred, inspired war, justified torture, divided countries, prevented education, increased disparities in wealth, and destroyed civilizations...there is a single underlying cause: a brain that evolved an unconscious capacity to seek differences between self and other, and once identified, seek to demote the other in the service of selfish gains... The good news is that science is uncovering some of the details of this destructive capacity, and may hold the key to an applied solution. My optimism: if we play our cards correctly, we may see the day when our instinctive prejudice toward the other will dissolve, gaining greater respect for differences, expanding our moral circle."
Among the items Hauser suggests in a possible playbook:
"Recognize the universality of our moral intuitions...Remove the doctrinal rules and our intuitive moral psychology propels us to decide what is morally right or wrong based on general principles concerning the welfare of others and our own virtues. If the Protestant and Catholic Irish can see past their religious beliefs, empathize with the other, recognize their shared underlying humanity and settle into peaceful co-existence, why not other warring factions?"
"Be vigilant of disgust...Although disgust was born out of an adaptive response to potential disease vectors, things that are normally inside but are now outside such as vomit, blood, and feces, it is a mischievous emotion, sneaking into other problems, alighting, wreaking havoc on group structure, and then spreading. Throughout the history of warfare, every warring group has tagged their enemy with qualities that are reminiscent of disease, filth, and parasites."
Smell of male sweat raises cortisol levels in women.
The use of chemosignals in other mammals has been well documented, especially in rats. Wyart et al. have now found that if women simply smell pure androstadienone (4,16-androstadien-3-one), which is present in the sweat of men, they maintain higher levels of the stress hormone cortisol.
Distortions of world view
Chris Anderson notes how "Certain types of news — for example dramatic disasters and terrorist actions — are massively over-reported, others — such as scientific progress and meaningful statistical surveys of the state of the world — massively under-reported." This derives from: "a deep human psychological response. We're wired to react more strongly to dramatic stories than to abstract facts. There are obvious historical and Darwinian reasons why this should be so. The news that an invader has just set fire to a hut in your village demands immediate response. The genes for equanimity in such circumstances got burned up long ago...Although our village is now global, we still instinctively react the same way. Spectacle, death and gore."
"Percentage of males estimated to have died in violence in hunter gatherer societies? Approximately 30%. Percentage of males who died in violence in the 20th century complete with two world wars and a couple of nukes? Approximately 1%. ...a carefully researched Human Security Report concluded that the numbers of armed conflicts in the world had fallen 40% in little over a decade." (Steven Pinker's essay in the "What are you optimistic about" series also notes the decline of force over the centuries and hopes that it is a real phenomenon, the product of systematic forces that will continue to operate, and that we can identify those forces and perhaps concentrate and bottle them.)
"In fact, most meta-level reporting of trends show a world that is getting better. We live longer, in cleaner environments, are healthier, and have access to goods and experiences that kings of old could never have dreamed of. If that doesn't make us happier, we really have no one to blame except ourselves. Oh, and the media lackeys who continue to feed us the litany of woes that we subconsciously crave."
"Percentage of males estimated to have died in violence in hunter gatherer societies? Approximately 30%. Percentage of males who died in violence in the 20th century complete with two world wars and a couple of nukes? Approximately 1%. ...a carefully researched Human Security Report concluded that the numbers of armed conflicts in the world had fallen 40% in little over a decade." (Steven Pinker's essay in the "What are you optimistic about" series also notes the decline of force over the centuries and hopes that it is a real phenomenon, the product of systematic forces that will continue to operate, and that we can identify those forces and perhaps concentrate and bottle them.)
"In fact, most meta-level reporting of trends show a world that is getting better. We live longer, in cleaner environments, are healthier, and have access to goods and experiences that kings of old could never have dreamed of. If that doesn't make us happier, we really have no one to blame except ourselves. Oh, and the media lackeys who continue to feed us the litany of woes that we subconsciously crave."
Monday, February 12, 2007
Evaporation of the Mystique of Religion
Dennett suggests that as young people are exposed to the worldwide spread of information technology, they quietly walk away from the faith of their parents and grandparents. (Side note: I thought I would show you, as an example of shifting fundamental attitudes, a figure from this Andrew Sullilvan post on the increase in the percentage of people who consider homosexuality acceptable, by year and by age group).
A brain correlate of subjective well-being.
Carlen et al. in Richard Davidson's laboratory at Wisconsin have used functional magnetic resonance imaging to examine: "whether individual differences in amygdala activation in response to negative relative to neutral information are related to differences in the speed with which such information is evaluated, the extent to which such differences are associated with medial prefrontal cortex function, and their relationship with measures of trait anxiety and psychological well-being (PWB)...faster judgments of negative relative to neutral information were associated with increased left and right amygdala activation. In the prefrontal cortex, faster judgment time was associated with relative decreased activation in a cluster in the ventral anterior cingulate cortex (ACC, Brodman Area 24). Furthermore, people who were slower to evaluate negative versus neutral information reported higher PWB. Importantly, higher PWB was strongly associated with increased activation in the ventral ACC for negative relative to neutral information.
Figure: Activity in the Ventral Anterior Cingulate predicts judgement time.
Figure: Activity in the ventral ACC in response to negative versus neutral images is positively associated with total PWB.
These findings suggest that people high in PWB effectively recruit the ventral ACC when confronted with potentially aversive stimuli, manifest reduced activity in subcortical regions such as the amygdala, and appraise such information as less salient as reflected in slower evaluative speed.
Figure: Activity in the Ventral Anterior Cingulate predicts judgement time.
Figure: Activity in the ventral ACC in response to negative versus neutral images is positively associated with total PWB.
These findings suggest that people high in PWB effectively recruit the ventral ACC when confronted with potentially aversive stimuli, manifest reduced activity in subcortical regions such as the amygdala, and appraise such information as less salient as reflected in slower evaluative speed.
Friday, February 09, 2007
The Insula is having its ten minutes of fame...
Those interested in how the brain's parts work to put it all together find their focus shifting as recordings and data begin to appear for previously neglected or inaccessible areas. There have been periods of focus, for example, on the hippocampus (learning and memory) and amygdala (fear and other emotions). Now the insula, on the interior of the cortex, is being found central to our feeling experience. (If you enter insula in the search box to the left of this posting you will find it the subject of several previous posts, one here.) Blakeslee draws together an interesting summary in this week's science section of the New York Times.
Here are some clips from that article:
"... the insula “lights up” in brain scans when people crave drugs, feel pain, anticipate pain, empathize with others, listen to jokes, see disgust on someone’s face, are shunned in a social settings, listen to music, decide not to buy an item, see someone cheat and decide to punish them, and determine degrees of preference while eating chocolate. Damage to the insula can lead to apathy, loss of libido and an inability to tell fresh food from rotten."
credit: New York Times
"The insula itself is a sort of receiving zone that reads the physiological state of the entire body and then generates subjective feelings that can bring about actions, like eating, that keep the body in a state of internal balance. Information from the insula is relayed to other brain structures that appear to be involved in decision making, especially the anterior cingulate and prefrontal cortices...The insula was long ignored for two reasons, researchers said. First, because it is folded and tucked deep within the brain, scientists could not probe it with shallow electrodes. It took the invention of brain imaging techniques, such as functional magnetic resonance imaging, or fMRI, to watch it in action."
" ...the insula receives information from receptors in the skin and internal organs. Such receptors are nerve cells that specialize in different senses. Thus there are receptors that detect heat, cold, itch, pain, taste, hunger, thirst, muscle ache, visceral sensations and so-called air hunger, the need to breathe. The sense of touch and the sense of the body’s position in space are routed to different brain regions."
"All mammals have insulas that read their body condition... Information about the status of the body’s tissues and organs is carried from the receptors along distinct spinal pathways, into the brain stem and up to the posterior insula in the higher brain or cortex...Humans, and to a lesser degree the great apes, have evolved two innovations to their insulas that take this system of reading body states to a new level...One involves circuitry, the other a brand new type of brain cell...In humans, information about the body’s state takes a slightly different route inside the brain, picking up even more signals from the gut, the heart, the lungs and other internal organs. Then the human brain takes an extra step, Dr. Craig said. The information on bodily sensations is further routed to the front part of the insula, especially on the right side, which has undergone a huge expansion in humans and apes...The second major modification to the insula is a type of cell found in only humans, great apes, whales and possibly elephants... Humans have by far the greatest number of these cells, which are called VENs, short for Von Economo neurons, named for the scientist who first described them in 1925. VENs are large cigar-shaped cells tapered at each end, and they are found exclusively in the frontal insula and anterior cingulate cortex...Exactly what VENs are doing within this critical circuit is not yet known...but they are in the catbird seat for turning feelings and emotions into actions and intentions."
Here are some clips from that article:
"... the insula “lights up” in brain scans when people crave drugs, feel pain, anticipate pain, empathize with others, listen to jokes, see disgust on someone’s face, are shunned in a social settings, listen to music, decide not to buy an item, see someone cheat and decide to punish them, and determine degrees of preference while eating chocolate. Damage to the insula can lead to apathy, loss of libido and an inability to tell fresh food from rotten."
credit: New York Times"The insula itself is a sort of receiving zone that reads the physiological state of the entire body and then generates subjective feelings that can bring about actions, like eating, that keep the body in a state of internal balance. Information from the insula is relayed to other brain structures that appear to be involved in decision making, especially the anterior cingulate and prefrontal cortices...The insula was long ignored for two reasons, researchers said. First, because it is folded and tucked deep within the brain, scientists could not probe it with shallow electrodes. It took the invention of brain imaging techniques, such as functional magnetic resonance imaging, or fMRI, to watch it in action."
" ...the insula receives information from receptors in the skin and internal organs. Such receptors are nerve cells that specialize in different senses. Thus there are receptors that detect heat, cold, itch, pain, taste, hunger, thirst, muscle ache, visceral sensations and so-called air hunger, the need to breathe. The sense of touch and the sense of the body’s position in space are routed to different brain regions."
"All mammals have insulas that read their body condition... Information about the status of the body’s tissues and organs is carried from the receptors along distinct spinal pathways, into the brain stem and up to the posterior insula in the higher brain or cortex...Humans, and to a lesser degree the great apes, have evolved two innovations to their insulas that take this system of reading body states to a new level...One involves circuitry, the other a brand new type of brain cell...In humans, information about the body’s state takes a slightly different route inside the brain, picking up even more signals from the gut, the heart, the lungs and other internal organs. Then the human brain takes an extra step, Dr. Craig said. The information on bodily sensations is further routed to the front part of the insula, especially on the right side, which has undergone a huge expansion in humans and apes...The second major modification to the insula is a type of cell found in only humans, great apes, whales and possibly elephants... Humans have by far the greatest number of these cells, which are called VENs, short for Von Economo neurons, named for the scientist who first described them in 1925. VENs are large cigar-shaped cells tapered at each end, and they are found exclusively in the frontal insula and anterior cingulate cortex...Exactly what VENs are doing within this critical circuit is not yet known...but they are in the catbird seat for turning feelings and emotions into actions and intentions."
What kinds of things have minds?
Grey et al report that in a Web-based survey, people conclude that anything that has feelings (such as hunger or pride) and the ability to act (such as communicating or showing self-restraint) possesses a mind.
Thursday, February 08, 2007
MindBlog's 1st Anniversary - Dangerous Ideas
Here is the Feb. 8 2006 post ("Dangerous Ideas") with which I started this blog, no less relevant now than a year ago.
Edge.org is a website sponsored by the "Reality Club" (i.e. John Brockman, literary agent/impressario/socialite). Brockman has assembled a stable of scientists and other thinkers that he defines as a "third culture" that takes the place of traditional intellectuals in redefining who and what we are.... Each year a question is formulated for all to write on... In 2004 it was "What do you believe is true even though you cannot prove it?" The question for 2005 was "What is your dangerous idea?"
The responses organize themselves into several areas. Here are selected thumbnail summaries most directly relevant to human minds. I've not included cosmology and physics. Go to edge.org to read the essays
I. Nature of the human self or mind (by the way see my "I-Illusion" essay on my website):
Paulos - The self is a conceptual chimera
Shirky - Free will is going away
Nisbett - We are ignorant of our thinking processes
Horgan - We have no souls
Bloom - There are no souls, mind has a material basis.
Provine - This is all there is.
Anderson - Brains cannot become minds without bodies
Metzinger - Is being intellectually honest about the issue of free will compatible with preserving one's mental health?
Clark - Much of our behavior is determined by non-conscious, automatic uptake of cues and information
Turkle - Simulation will replace authenticity as computer simulation becomes fully naturalized.
Dawkins - A faulty person is no different from a faulty car. There is a mechanism determining behavior that needs to be fixed. The idea of responsibility is nonsense.
Smith - What we know may not change us. We will continue to conceive ourselves as centres of experience, self-knowing and free willing agents.
II. Natural explanations of culture
Sperber - Culture is natural.
Taylor - The human brain is a cultural artifact.
Hauser- There is a universal grammar of mental life.
Pinker - People differ genetically in their average talents and temperaments.
Goodwin - Similar coordinating patterns underlie biological and cultural evolution.
Venter - Revealing the genetic basis of personality and behavior will create societal conflicts.
III. Fundamental changes in political, economic, social order
O'donnell - The state will disappear.
Ridley - Government is the problem not the solution.
Shermer - Where goods cross frontiers armies won't.
Harari -Democracy is on its way out.
Csikszentmihalyi- The free market myth is destroying culture.
Goleman - The internet undermines the quality of human interaction.
Harris - Science must destroy religion.
Porco - Confrontation between science and religion might end when role played by science in lives of people is the same played by religion today.
Bering - Science will never silence God
Fisher - Drugs such as antidepressants jeopardize feelings of attachment and love
Iacoboni - Media Violence Induces Imitative Violence - the Problem with Mirrors
Morton - Our planet is not in peril, just humans are.
Edge.org is a website sponsored by the "Reality Club" (i.e. John Brockman, literary agent/impressario/socialite). Brockman has assembled a stable of scientists and other thinkers that he defines as a "third culture" that takes the place of traditional intellectuals in redefining who and what we are.... Each year a question is formulated for all to write on... In 2004 it was "What do you believe is true even though you cannot prove it?" The question for 2005 was "What is your dangerous idea?"
The responses organize themselves into several areas. Here are selected thumbnail summaries most directly relevant to human minds. I've not included cosmology and physics. Go to edge.org to read the essays
I. Nature of the human self or mind (by the way see my "I-Illusion" essay on my website):
Paulos - The self is a conceptual chimera
Shirky - Free will is going away
Nisbett - We are ignorant of our thinking processes
Horgan - We have no souls
Bloom - There are no souls, mind has a material basis.
Provine - This is all there is.
Anderson - Brains cannot become minds without bodies
Metzinger - Is being intellectually honest about the issue of free will compatible with preserving one's mental health?
Clark - Much of our behavior is determined by non-conscious, automatic uptake of cues and information
Turkle - Simulation will replace authenticity as computer simulation becomes fully naturalized.
Dawkins - A faulty person is no different from a faulty car. There is a mechanism determining behavior that needs to be fixed. The idea of responsibility is nonsense.
Smith - What we know may not change us. We will continue to conceive ourselves as centres of experience, self-knowing and free willing agents.
II. Natural explanations of culture
Sperber - Culture is natural.
Taylor - The human brain is a cultural artifact.
Hauser- There is a universal grammar of mental life.
Pinker - People differ genetically in their average talents and temperaments.
Goodwin - Similar coordinating patterns underlie biological and cultural evolution.
Venter - Revealing the genetic basis of personality and behavior will create societal conflicts.
III. Fundamental changes in political, economic, social order
O'donnell - The state will disappear.
Ridley - Government is the problem not the solution.
Shermer - Where goods cross frontiers armies won't.
Harari -Democracy is on its way out.
Csikszentmihalyi- The free market myth is destroying culture.
Goleman - The internet undermines the quality of human interaction.
Harris - Science must destroy religion.
Porco - Confrontation between science and religion might end when role played by science in lives of people is the same played by religion today.
Bering - Science will never silence God
Fisher - Drugs such as antidepressants jeopardize feelings of attachment and love
Iacoboni - Media Violence Induces Imitative Violence - the Problem with Mirrors
Morton - Our planet is not in peril, just humans are.
Wednesday, February 07, 2007
Objective measurement of awareness.
Studying consciousness is difficult because asking subjects to report their awareness of a stimulus perturbs that awareness. A new paper by Persaud and Cowey shows that asking subjects to wager on whether their response is correct can solve this problem.
From their paper: "The performance of any cognitive task, from recognizing a face to running a business, is an amalgam of many decisions. Some are made consciously and some are not. There is no agreed-upon way of determining which decisions are conscious. Simply asking people might seem a straightforward method, but they may deny awareness if the question asked does not relate to the method they think they used to reach the decision. Numerical confidence ratings have been suggested as an alternative to verbal report but participants may underrate their confidence or withhold conscious knowledge, as they are given no motivation to reveal it. Here we demonstrate that a newly created measure, post-decision wagering, in which people are offered cash rewards for revealing conscious knowledge, can be used to determine which decisions are made without awareness. We asked participants performing three very different tasks—visual discrimination in blindsight, string selection in an artificial grammar task and pack selection in the Iowa gambling task—to place wagers on the outcomes of their decisions. We found above chance performance in the tasks, but the wagers indicated a lack of awareness that the decisions were correct. By making it clear when awareness is absent, this method may help to answer one of the central questions of contemporary neuroscience: how does neural activity give rise to conscious experience?"
From their paper: "The performance of any cognitive task, from recognizing a face to running a business, is an amalgam of many decisions. Some are made consciously and some are not. There is no agreed-upon way of determining which decisions are conscious. Simply asking people might seem a straightforward method, but they may deny awareness if the question asked does not relate to the method they think they used to reach the decision. Numerical confidence ratings have been suggested as an alternative to verbal report but participants may underrate their confidence or withhold conscious knowledge, as they are given no motivation to reveal it. Here we demonstrate that a newly created measure, post-decision wagering, in which people are offered cash rewards for revealing conscious knowledge, can be used to determine which decisions are made without awareness. We asked participants performing three very different tasks—visual discrimination in blindsight, string selection in an artificial grammar task and pack selection in the Iowa gambling task—to place wagers on the outcomes of their decisions. We found above chance performance in the tasks, but the wagers indicated a lack of awareness that the decisions were correct. By making it clear when awareness is absent, this method may help to answer one of the central questions of contemporary neuroscience: how does neural activity give rise to conscious experience?"
Innate motion perception in 4-day old human babies
A single point of light can be moved about in a biological or non-biological manner. Meary et al. report that 4-day old human neonates look longer at the non-biological motions, suggesting violation of an expectation. This indicates that neonates' motion perception — like adults'—is attuned to biological kinematics.
Tuesday, February 06, 2007
Watching a computer "be nice" activates our brain's agency and goal detectors
A review by Montague and Chiu and article by Tankersley et al. describe studies showing that watching a computer perform an altruistic act, earning monitary points for charity (in contrast with human subjects playing the game themselves), activates the posterior superior temporal sulcus (pSTS). This brain region is important for considering the goals and intentions of other beings and specifically for understanding the behavior of social agents as they relate to the goals of a social interaction. An important point differentiates this work from other studies: the computer is an agent only in that the human player has been instructed that it is generating a purposeful act (earning money for a cause). Without these instructions, the human participant is simply viewing a series of flashing symbols, and the experiment might as well assess questions about visual perception. The pSTS may thus be implicated in generic computations about agency, regardless of whether a social interaction is involved.
Figure: Increased right pSTC activation to action perception compared with action performance.
Figure: Increased right pSTC activation to action perception compared with action performance.
Fish brains can perform transitive analysis
Yesterday's post on fish brains switching their sexuality reminds me of another bit of work on fish that I have been meaning to mention:
Transitive inference involves using known relationships to deduce unknown ones (for example, using A > B and B > C to infer A > C), and is thus essential to logical reasoning. First described as a developmental milestone in children, Transitive inference has since been reported in nonhuman primates, rats, and birds.
In many social species (whether they are teleost fish or mammals) a behavioral hierarchy establishes itself which regulates who gets first access to food and mates. A reason that transitive behavior would evolve is that it saves a lot of energy if you don't have to go into head on competition with every other male you meet to determine who is on top. If you can see competitions between other males and learn who wins over who, you learn who is safer to hang out with. This rationale should be true for both territorial and non-territorial species that maintain social hierarchies, so you might not be surprised to find it wherever such hierarchies are established.
Experiments in Fernald's lab at Stanford now show that male fish (Astatotilapia burtoni) can successfully make inferences on a hierarchy implied by pairwise fights between rival males. These fish learned the implied hierarchy vicariously (as 'bystanders'), by watching fights between rivals arranged around them in separate tank units.
What this says about fish brains is that they can perform a transitive analysis, just as they can do many other quite amazing feats of analysis. It does not say anything about the kind of experienced awareness or consciousness they have. It could a process as automatic and rote as the operant conditioning which trains them to avoid stimuli in the past have resulted in dangerous or unpleasant experiences.
Transitive inference involves using known relationships to deduce unknown ones (for example, using A > B and B > C to infer A > C), and is thus essential to logical reasoning. First described as a developmental milestone in children, Transitive inference has since been reported in nonhuman primates, rats, and birds.
In many social species (whether they are teleost fish or mammals) a behavioral hierarchy establishes itself which regulates who gets first access to food and mates. A reason that transitive behavior would evolve is that it saves a lot of energy if you don't have to go into head on competition with every other male you meet to determine who is on top. If you can see competitions between other males and learn who wins over who, you learn who is safer to hang out with. This rationale should be true for both territorial and non-territorial species that maintain social hierarchies, so you might not be surprised to find it wherever such hierarchies are established.
Experiments in Fernald's lab at Stanford now show that male fish (Astatotilapia burtoni) can successfully make inferences on a hierarchy implied by pairwise fights between rival males. These fish learned the implied hierarchy vicariously (as 'bystanders'), by watching fights between rivals arranged around them in separate tank units.
What this says about fish brains is that they can perform a transitive analysis, just as they can do many other quite amazing feats of analysis. It does not say anything about the kind of experienced awareness or consciousness they have. It could a process as automatic and rote as the operant conditioning which trains them to avoid stimuli in the past have resulted in dangerous or unpleasant experiences.
Monday, February 05, 2007
Switch brain sexuality with steroid hormones!
OK, so it is actually a fish doing it. But, Remage-Healey and Bass suggest that their findings may help explain the widespread distribution of rapidly induced intrasexual behavioral phenotypes among vertebrates in general. They observe that the male acoustic sexual behavior of the teleost type I male midshipman can be rapidly (~ 5 min) induced in type II males (that normally show female like behaviors) by the action of the androgen 11-ketotestosterone on receptors in the brain's vocal pattern generator. (11-ketotestosterone is the dominant circulating androgen in type I males, and testosterone is the dominant androgen in type II males and females). This suggests that steroid-dependent expression of "maleness" and "femaleness" may now include rapid steroid actions on the neurophysiological patterning of behavior, uncoupled from gonadal phenotype.
Friday, February 02, 2007
Body Hot Spots
I just came across a complete web version of this book by R. Dale Guthrie which I enjoyed reading in the 1970s. Its perspective on the mixes of behavior and anatomy that comprise our social organs continues to be an original one.
Paradise-engineering
Another curious site, with futuristic essays on abolishing pain and unhappiness.
Thursday, February 01, 2007
More on faces....
Check out this site that invites you to sign up for experiments on face and voice preferences.
Expressing learned, but not innate, fear requires the prefrontal cortex.
Corcoran and Quirk have blocked nerve signals (using the sodium channel blocker tetradotoxin) in the prelimbic subregion of the medial prefrontal cortex (PL) of rats during fear learning and expression. Inactivation of PL reduced freezing to both a tone and a context that had been previously paired with footshock (learned fear) but had no effect on freezing to a cat (innate fear). Inactivation of PL before conditioning, however, did not prevent the formation of auditory or contextual fear memories. Thus, activity in PL is critical for the expression, but not the acquisition, of learned fears. They suggest that PL integrates information from auditory and contextual inputs and regulates expression of fear memories via projections to the basal nucleus of the amygdala.
Neural Basis of Loss Aversion
Tom et al show that activity in the ventral striatum and ventromedial prefrontal cortex appears to correlate with judgments of potential loses versus gains in monetary choices. Activity in brain structures thought to mediate negative emotions in decision-making (such as the amygdala or anterior insula) does not change.
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