Immune system subjugation of the brain

Research on links between brain, behavior, and the immune system is expanding rapidly. It has long been known that depression lowers immunity, and Dantzer et al. offer a review of causality in the opposite direction: release of cytokines by the innate immune system during infection which in the short term triggers sickness behaviors in the long term can cause depression. Here is their abstract and a PDF.

In response to a peripheral infection, innate immune cells produce pro-inflammatory cytokines that act on the brain to cause sickness behaviour. When activation of the peripheral immune system continues unabated, such as during systemic infections, cancer or autoimmune diseases, the ensuing immune signalling to the brain can lead to an exacerbation of sickness and the development of symptoms of depression in vulnerable individuals. These phenomena might account for the increased prevalence of clinical depression in physically ill people. Inflammation is therefore an important biological event that might increase the risk of major depressive episodes, much like the more traditional psychosocial factors.

Does the internet liberate or enslave us?

A book by Lee Siegel "Against the Machine," reviewed by Janet Maslin in the NY Times, and an essay by Nicholas Carr raise a related set of arguments that challenge the assumption that the internet is a liberating force, a force for freedom, diffusing power and information among the many, rather than the few. At the same time web traffic in increasing, it is becoming more centralized. Carr notes:

-During the five years from 2002 through 2006, the number of Internet sites nearly doubled, yet the concentration of traffic at the ten most popular sites nonetheless grew substantially, from 31% to 40% of all page views
-Google continues to expand its hegemony...In March 2006, the company's search engine was used to process a whopping 58% of all searches in the United States, according to Hitwise. By November 2007, the figure had increased yet again, to 65%. The results of searches are also becoming more, not less, homogeneous. Do a search for any common subject, and you're almost guaranteed to find Wikipedia at or near the top of the list of results.
-Executives of Yahoo and Sun Microsystems have recently predicted that control over the net's computing infrastructure will ultimately lie in the hands of five or six organizations.
-To what end will the web giants deploy their power? They will, of course, seek to further their own commercial or political interests by monitoring, analyzing, and manipulating the behavior of "users." ...What's different, in comparison to the physical world, is that acts of control are more difficult to detect.

Graphical depiction of the Internet as consisting of a dense core of 80 or so critical nodes surrounded by an outer shell of 5,000 sparsely connected, isolated nodes that are very much dependent upon this core. (Shai Carmi, Bar Ilan University)

Siegel deals with socially toxic effects of the internet. From Maslin's review, describing Siegle's account of Starbucks, as one is:

...surrounded by Internet zombies, laptop-addicted creatures who have so grievously lost their capacity for human interaction “that social space has been contracted into isolated points of wanting, all locked into separate phases of inwardness.”...the semblance of a shared Starbucks experience masks endemic computer-generated isolation, a condition that has prompted psychic and ethical breakdowns that go well beyond the collapse of community....why we are living so gullibly through what would have been the plot of a science-fiction movie 15 years ago. Why does the freedom promised by the Internet feel so regimented and constricting? Why do its forms of democracy have their totalitarian side? What happens to popular culture when its sole emphasis is on popularity? How have we gone “from ‘I love that thing he does!’ to ‘Look at all those page views!’ in just a few years”?

Remember Disco??

I saw this video (So Many Men, So Little Time - Miquel Brown) during happy hour at the local bar (Georgie's Alibi) several evenings ago and was totally transported back to my days of disco dancing in the late 1970's, early 1980's, getting hot and sweaty, tearing off the shirt, etc. The same moves at my current age would probably be life-threatening. I'll bet a number of you remember this kind of energy...

The myth of the mid-life crisis.

Here is an engaging article by Richard Freedman on the supposed crisis around age 50 (mainly in men) when the first signs of physical decline and the questions and doubts about one’s personal and professional accomplishments emerge.

..some find themselves seized by a seemingly irresistible impulse to do something dramatic, even foolish. Everything, it appears, is fair game for a midlife crisis: one’s job, spouse, lover — you name it.

Freedman outlines:

a garden-variety case of a middle-aged narcissist grappling with the biggest insult he had ever faced: getting older...But you have to admit that “I’m having a midlife crisis” sounds a lot better than “I’m a narcissistic jerk having a meltdown.”

Another source of the midlife 'crisis' :

...reaching a situation...of having to seriously take account of someone else’s needs, such as those of children, for the first time.

Further clips:

Why do we have to label a common reaction of the male species to one of life’s challenges — the boredom of the routine — as a crisis? True, men are generally more novelty-seeking than women, but they certainly can decide what they do with their impulses.

The main culprit, I think, is our youth-obsessed culture, which makes a virtue of the relentless pursuit of self-renewal. The news media abound with stories of people who seek to recapture their youth simply by shedding their spouses, quitting their jobs or leaving their families. Who can resist?..Most middle-aged people, it turns out, if we are to believe the definitive survey...Except, of course, for the few — mainly men, it seems — who find the midlife crisis a socially acceptable shorthand for what you do when you suddenly wake up and discover that you’re not 20 anymore.

Terror alerts kill more people than terrorists in the US?

I have long held the opinion, reinforced by this article in the NYTimes, that the absurd terror alert system devised by the department of "homeland security" kills more people than the potential terrorist threat, given that "the chances of the average person dying in America at the hands of international terrorists to be comparable to the risk of dying from eating peanuts, being struck by an asteroid or drowning in a toilet." The article describes studies on a cohort of 2,700 people studied before and after the Sept. 11 attack which indicate a correlation (which is not a cause) between expressed anxiety over a terrorist attack and subsequent cardiovascular ailments.

The Impressionable Brain

I want to pass on this essay by Marcel Kinsbourne, which is an interesting exegesis of the implication of mirror neuron systems in our brain, especially with respect to possibly making moot the issue of brain versus environmental effects:

When the phenomenon of "mirror neurons" that fire both when a specific action is perceived and when it is intended was first reported, I was impressed by the research but skeptical about its significance...I have come to realize that mirror neurons are not only less than meets the eye but also more. Instead of being a specific specialization, they play their role as part of a fundamental design characteristic of the brain; that is, when percepts are activated, relevant intentions, memories and feelings automatically fall into place.

That an individual is likely to act in the same ways that others act is seen in the documented benefit for sports training of watching experts perform. "Emotional contagion" occurs when someone witnesses the emotional expressions of another person and therefore experiences that mood state oneself. People's viewpoints can subtly and unconsciously converge when their patterns of neural activation match, in the total absence of argument or attempts at persuasion. When people entrain with each other in gatherings, crowds, assemblies and mobs, diverse individual views reduce into a unified group viewpoint.

People's views are surreptitiously shaped by their experiences, and rationality comes limping after, downgraded to rationalization. Once opinions are established, they engender corresponding anticipations. People actively seek those experiences that corroborate their own self-serving expectations. This may be why as we grow older, we become ever more like ourselves. Insights become consolidated and biases reinforced when one only pays attention to confirming evidence. Diverse mutually contradictory "firm convictions" are the result.

If I am correct in my changed views as to what mirror neurons stand for and how representation routinely merges perception, action, memory and affect into dynamic reciprocal interaction, these views would have a bearing on currently disputed issues. Whether an effect is due to the brain or the environment would be moot if environmental causes indeed become brain causes, as the impressionable brain resonates with changing circumstances. What we experience contributes mightily to what we are and what we become.

What people experience indeed changes their brain, for better and for worse. In turn, the changed brain changes what is experienced. Regardless of its apparent stability over time, the brain is in constant flux, and constantly remodels. Heraclitus was right: "You shall not go down twice to the same river". The river will not be the same, but for that matter, neither will you. We are never the same person twice. The past is etched into the neural network, biasing what the brain is and does in the present. William Faulkner recognized this: "The past is never dead. In fact, it's not even past".

Antidepressant effects of exercise - a mechanism

Here is an interesting bit from Hunsberger et al. in Nature Medicine, which suggests that a nerve growth factor pathway might be a target for antidepressant drug development (exercise might do the same thing, but depressed people usually aren't that keen on working out):

Exercise has many health benefits, including antidepressant actions in depressed human subjects, but the mechanisms underlying these effects have not been elucidated. We used a custom microarray to identify a previously undescribed profile of exercise-regulated genes in the mouse hippocampus, a brain region implicated in mood and antidepressant response. Pathway analysis of the regulated genes shows that exercise upregulates a neurotrophic factor signaling cascade that has been implicated in the actions of antidepressants. One of the most highly regulated target genes of exercise and of the growth factor pathway is the gene encoding the VGF nerve growth factor, a peptide precursor previously shown to influence synaptic plasticity and metabolism. We show that administration of a synthetic VGF-derived peptide produces a robust antidepressant response in mice and, conversely, that mutation of VGF in mice produces the opposite effects. The results suggest a new role for VGF and identify VGF signaling as a potential therapeutic target for antidepressant drug development.

GENES R US

This clip from the Jan. 20 issue of Science:

Personal genomics revved into high gear last year thanks to DNA chips that make it possible to cheaply scan the entire genome (Science, 21 December 2007, p. 1842). You can track the flood of new discoveries at SNPedia (www.snpedia.com), a Web site run by two biotech veterans in Bethesda, Maryland, that catalogs SNPs culled from the literature.

SNPs are single-nucleotide polymorphisms: single-base variations in DNA that researchers are tying to traits and disease risks. Browse by medical conditions (77 so far) and discover, for example, that carrying two copies of the T version of a SNP called rs2273535 raises your risk of colon cancer by 50%; another SNP, rs6152, is associated with baldness. Visitors can also search by genetically influenced drug reactions (48) and genes (128). There are links to relevant papers and sites (including James Watson's and J. Craig Venter's respective genomes) and to blogs by people who are sending their DNA to a lab to be "SNP chipped." The site is also a wiki, which means anyone can contribute.

The site "could be a very valuable research tool," says computational biologist Mark Daly of the Broad Institute in Cambridge, Massachusetts. "It will be great to see how this develops."

A Debussy Ballade - music for the start of the week

The only downside of being in Ft. Lauderdale FL. (sunny, 81 degress on Saturday) versus Madison, WI. (-7 degress, cloudy) is that my Steinway B grand piano stays in Madison. I have now installed a credible Steinway upright in the Ft. Lauderdale condo and have decided to continue on it the sort of video recordings I had been doing in Madison. I may re-record this piece on the better piano when I get back to Madison in the spring.

The bouncer in the brain...

In the January issue of Nature Neuroscience a review with the title of this post by Awh & Vogel discusses experiments by McNab & Klingberg that may explain why there are significant differences between individuals in working memory, which is known to be limited to about three or four items. Individual differences in this memory capacity correlate robustly with measures of fluid intelligence and scholastic aptitude. The experiments explore the idea that variations in the efficiency with which information is selected to fill this limited workspace are involved. From Awh and Vogel:

One perspective on individual differences in memory capacity views variation in terms of the number of 'slots' that are available for short-term storage. However, apparent capacity differences might also be explained by variations in the efficiency with which information is selected to fill this limited workspace. A useful analogy for understanding the difference between these two ideas is the difference between the space that is available in an exclusive nightclub and the effectiveness of the bouncer who grants admission. From this perspective, high-capacity individuals may have a better bouncer rather than a larger nightclub...brain imaging evidence from McNab and Klingberg implicates a specific neural region that may serve as the bouncer for the mind.

This hypothesis is consistent with a growing body of evidence that shows tight links between attention and working memory. Some theorists have even suggested that they are essentially the same mechanism. This viewpoint is supported by the strong overlap in the cortical areas that are active during attention and working-memory tasks, as well as evidence that directly implicates attention in the active maintenance of information in working memory. Furthermore, an individual's working-memory capacity is highly predictive of his or her performance on a wide range of attention tasks

Here is the abstract from McNab and Klingberg:

Our capacity to store information in working memory might be determined by the degree to which only relevant information is remembered. The question remains as to how this selection of relevant items to be remembered is accomplished. Here we show that activity in the prefrontal cortex and basal ganglia preceded the filtering of irrelevant information and that activity, particularly in the globus pallidus, predicted the extent to which only relevant information is stored. The preceding frontal and basal ganglia activity were also associated with inter-individual differences in working memory capacity. These findings reveal a mechanism by which frontal and basal ganglia activity exerts attentional control over access to working memory storage in the parietal cortex in humans, and makes an important contribution to inter-individual differences in working memory capacity.

Meditation Research

The Mind and Life Institute offers a quarterly bibliography with short descriptions of research work done of the effects of mindfulness-based cognitive therapy.

Pinker on the 'moral instinct'

It would have been nice to put a discussion of Pinker's NY Times Magazine article alongside the post on Metzinger's essay "There are no moral facts" but I didn't get around to it in time. Pinker is an exceptionally bright and clear writer. Even so, a bit of nit-picking can't be resisted, a few of his sentences have hidden land mines. Take for example:

...dissecting moral intuitions is no small matter. If morality is a mere trick of the brain, some may fear, our very grounds for being moral could be eroded. Yet as we shall see, the science of the moral sense can instead be seen as a way to strengthen those grounds, by clarifying what morality is and how it should steer our actions.

A continuous drumbeat throughout this blog has been to make the point that even our sense of having a purposeful "I" is a 'mere trick of the brain' (See also The "I" Illusion). A damned useful one, to be sure, that has resulted in a our dominance as a species on this planet. Seen in the light of evolution, an evolved moral sense can also be viewed as a yet more refined way of passing on or genes, and influencing the competition between groups of humans that has driven recent human evolution. Pinker's "how morality should steer our actions" flirts with the "naturalistic fallacy" (because this is what our biology gives us, it is the way things should be.) That "should" is relevant to passing on our genes, not to any ultimate criteria for morality. Metzinger's essay nails it:

...all we have to go by are the contingent moral intuitions evolution has hard-wired into our emotional self-model. If we choose to simply go by what feels good, then our future is easy to predict: It will be primitive hedonism and organized religion.

Or, take this gem from Pinker's article:

Though no one has identified genes for morality, there is circumstantial evidence they exist. The character traits called “conscientiousness” and “agreeableness” are far more correlated in identical twins separated at birth (who share their genes but not their environment) than in adoptive siblings raised together (who share their environment but not their genes). People given diagnoses of “antisocial personality disorder” or “psychopathy” show signs of morality blindness from the time they are children.

The villain here is the phrase "genes for morality". By now, most popularizers have left behind phrases like this, because it implies a causality that does not exist. Genes are not for anything by themselves, but have an unfolding expression that requires vastly complex interactions with other genes and the environment. They can be "permissive of..." or "increase the probability of..." a particular outcome, but they don't run the show. This why the phrase "genes for X" (where X is any complex behavior) should not be used.

Pinker proceeds through of very elegant and structured review of moralization switches, reasoning and rationalizing (including examples such as the well known "Trolley Problem" - for other examples see MindBlog's 'morality' category in the left column of the web page your are viewing.)

One of his best lines is: "When psychologists say “most people” they usually mean “most of the two dozen sophomores who filled out a questionnaire for beer money.”

Further topics include the idea of a universal morality, varieties of moral experience, and the genealogy of morals. He does a nice discussion of the five spheres of moral behavior that are shared by humans and many animals living in groups, suggesting ancient evolutionary origins of the behaviors (doing harm, fairness, community, authority, purity).

My favorite section in the esay is "Is morality a figment", where Pinker partially, but not completely addresses the first issue I raised above. Here is a clip, on where moral reasons might come from:

They certainly aren’t in the physical world like wavelength or mass. The only other option is that moral truths exist in some abstract Platonic realm, there for us to discover, perhaps in the same way that mathematical truths (according to most mathematicians) are there for us to discover. On this analogy, we are born with a rudimentary concept of number, but as soon as we build on it with formal mathematical reasoning, the nature of mathematical reality forces us to discover some truths and not others. (No one who understands the concept of two, the concept of four and the concept of addition can come to any conclusion but that 2 + 2 = 4.) Perhaps we are born with a rudimentary moral sense, and as soon as we build on it with moral reasoning, the nature of moral reality forces us to some conclusions but not others.

Moral realism, as this idea is called, is too rich for many philosophers’ blood. Yet a diluted version of the idea — if not a list of cosmically inscribed Thou-Shalts, then at least a few If-Thens — is not crazy. Two features of reality point any rational, self-preserving social agent in a moral direction. And they could provide a benchmark for determining when the judgments of our moral sense are aligned with morality itself.

One is the prevalence of nonzero-sum games. In many arenas of life, two parties are objectively better off if they both act in a nonselfish way than if each of them acts selfishly. ... Any neutral observer, and you and I if we could talk it over rationally, would have to conclude that the state we should aim for is the one in which we both are unselfish. These spreadsheet projections are not quirks of brain wiring, nor are they dictated by a supernatural power; they are in the nature of things.

The other external support for morality is a feature of rationality itself: that it cannot depend on the egocentric vantage point of the reasoner. If I appeal to you to do anything that affects me — to get off my foot, or tell me the time or not run me over with your car — then I can’t do it in a way that privileges my interests over yours (say, retaining my right to run you over with my car) if I want you to take me seriously. Unless I am Galactic Overlord, I have to state my case in a way that would force me to treat you in kind. I can’t act as if my interests are special just because I’m me and you’re not, any more than I can persuade you that the spot I am standing on is a special place in the universe just because I happen to be standing on it.

Not coincidentally, the core of this idea — the interchangeability of perspectives — keeps reappearing in history’s best-thought-through moral philosophies, including the Golden Rule (itself discovered many times); Spinoza’s Viewpoint of Eternity; the Social Contract of Hobbes, Rousseau and Locke; Kant’s Categorical Imperative; and Rawls’s Veil of Ignorance. It also underlies Peter Singer’s theory of the Expanding Circle — the optimistic proposal that our moral sense, though shaped by evolution to overvalue self, kin and clan, can propel us on a path of moral progress, as our reasoning forces us to generalize it to larger and larger circles of sentient beings.

Exercise effects on brain and cognition

Hillman et al., provide an interesting review article (PDF here) that examines the positive effects of aerobic physical activity on cognition and brain function, at the molecular, cellular, systems and behavioral levels.

The results of a meta-analysis of the effects of fitness training on cognition showed that the benefits of fitness training on four different cognitive tasks were significant. As illustrated in the figure, fitness training has both broad and specific effects. The effects are broad in the sense that individuals in aerobic fitness training groups (represented by the red bars) showed larger fitness training effects across the different categories of cognitive processes illustrated on the x-axis. They are specific in the sense that fitness training effects were larger for some cognitive processes, in particular executive control processes, than for other cognitive processes.

Physical activity has been found to enhance cognition, with a selectively larger effect on executive control functions compared with other cognitive processes. Accordingly, brain structures that mediate executive functions would be expected to show disproportionate changes as a result of participation in physical activity. One such structure is the anterior cingulate cortex (ACC), which is part of the brain's limbic system and has connections with multiple brain structures that process sensory, motor, emotional and cognitive information. Two convergent lines of research indicate that physical activity exerts a substantial influence on the ACC and the concomitant executive processes that it mediates.

Permanent Reincarnation

Here are some clips from an interesting essay by science writer Tor Norretranders:

My body is not like a typical material object, a stable thing. It is more like a flame, a river or an eddie. Matter is flowing through it all the time. The constituents are being replaced over and over again...98 percent of the atoms in the body are replaced every year. 98 percent! Water molecules stays in your body for two weeks (and for an even shorter time in a hot climate), the atoms in your bones stays there for a few months. Some atoms stay for years. But almost not one single atom stay with you in your body from cradle to grave...What is constant in you is not material. An average person takes in 1.5 ton of matter every year as food, drinks and oxygen. All this matter has to learn to be you. Every year. New atoms will have to learn to remember your childhood.

These numbers has been known for half a century or more, mostly from studies of radioactive isotopes. Physicist Richard Feynman said in 1955: "Last week's potatoes! They now can remember what was going on in your mind a year ago."

But digital media now makes it possible to think of all this in a simple way. The music I danced to as a teenager has been moved from vinyl-LPs to magnetic audio tapes to CDs to Pods and whatnot. The physical representation can change and is not important — as long as it is there. The music can jump from medium to medium, but it is lost if it does not have a representation. This physics of information was sorted out by Rolf Landauer in the 1960'ies. Likewise, out memories can move from potato-atoms to burger-atoms to banana-atoms. But the moment they are on their own, they are lost.

We reincarnate ourselves all the time. We constantly give our personality new flesh. I keep my mental life alive by making it jump from atom to atom. A constant flow. Never the same atoms, always the same river. No flow, no river. No flow, no me...This is what I call permanent reincarnation: Software replacing its hardware all the time. Atoms replacing atoms all the time. Life. This is very different from religious reincarnation with souls jumping from body to body (and souls sitting out there waiting for a body to take home in).

Coevolution of choosiness and cooperation

An interesting modeling article by McNamara et al. suggests a novel evolutionary mechanism based on a positive coevolutionary feedback between cooperativeness and choosiness. If individuals vary in their degree of cooperativeness, and if they can decide whether or not to continue interacting with each other on the basis of their respective levels of cooperativeness, then cooperation can gradually evolve from an uncooperative state. When an individual's cooperativeness is used by other individuals as a choice criterion, there can be competition to be more generous than others (competetive altruism). The evolution of cooperation between non-relatives can then be driven by a positive feedback between increasing levels of cooperativeness and choosiness. In this model, individual behavioural differences are the key to the evolution of cooperation. Because the model does not invoke complex mechanisms such as negotiation behaviour, it can be applied to a wide range of species.

The model calculations use an infinite population where, in each of a discrete series of time steps (rounds), pairs of individuals engage in a game that can be described as a social dilemma. Each individual is characterized by two traits: a cooperativeness trait x, which specifies the amount of effort that the individual devotes to generating benefits available (at least in part) to its co-player; and a choosiness trait y, which specifies the minimum degree of cooperativeness that the focal individual is prepared to accept from its co-player. The traits x and y are genetically determined and are not adjusted in response to the co-player's behaviour. Thus, unlike in many models in which flexible effort adjustment is a key ingredient1, individuals in their model are consistent in their degree of cooperativeness.

Planned Obsolescence? The Four-Year Itch

Helen Fisher, author of "Why We Love" and an anthropology professor at Rutgers, has written a brief essay with the title of this post. She did a cross cultural survey of when divorces occur and found that divorces regularly peaked during and around the fourth year after wedding (no evidence for the commonly assumed seven year itch indicated in the graphic). Divorces peaked among couples in their late twenties. And the more children a couple had, the less likely they were to divorce: some 39% of worldwide divorces occurred among couples with no dependent children; 26% occurred among those with one child; 19% occurred among couples with two children; and 7% of divorces occurred among couples with three young. In trying to figure out so many men and women divorce during and around the 4-year mark; at the height of their reproductive years; and often with a single child, she had an "a ha" moment:

Women in hunting and gathering societies breastfeed around the clock, eat a low-fat diet and get a lot of exercise — habits that tend to inhibit ovulation. As a result, they regularly space their children about four years apart. Thus, the modern duration of many marriages—about four years—conforms to the traditional period of human birth spacing, four years.

Perhaps human parental bonds originally evolved to last only long enough to raise a single child through infancy, about four years, unless a second infant was conceived. By age five, a youngster could be reared by mother and a host of relatives. Equally important, both parents could choose a new partner and bear more varied young.

Her theory fits with data on other species:

Only about three percent of mammals form a pairbond to rear their young. Take foxes. The vixen's milk is low in fat and protein; she must feed her kits constantly; and she will starve unless the dog fox brings her food. So foxes pair in February and rear their young together. But when the kits leave the den in mid summer, the pairbond breaks up. Among foxes, the partnership lasts only through the breeding season. This pattern is common in birds. Among the more than 8,000 avian species, some 90% form a pairbond to rear their young. But most do not pair for life. A male and female robin, for example, form a bond in the early spring and rear one or more broods together. But when the last of the fledgling fly away, the pairbond breaks up... Like pair-bonding in many other creatures, humans have probably inherited a tendency to love and love again—to create more genetic variety in our young.

The neural control of vigor

An interesting article from Dolan's laboratory on the neural substrates of the motivation and vigor with which we perform actions. Their abstract lays it out clearly:

The vigor with which a participant performs actions that produce valuable outcomes is subject to a complex set of motivational influences. Many of these are believed to involve the amygdala and the nucleus accumbens, which act as an interface between limbic and motor systems. One prominent class of influences is called pavlovian–instrumental transfer (PIT), in which the motivational characteristics of a predictor influence the vigor of an action with respect to which it is formally completely independent. We provide a demonstration of behavioral PIT in humans, with an audiovisual predictor of the noncontingent delivery of money inducing participants to perform more avidly an action involving squeezing a handgrip to earn money. Furthermore, using functional magnetic resonance imaging, we show that this enhanced motivation was associated with a trial-by-trial correlation with the blood oxygenation level-dependent (BOLD) signal in the nucleus accumbens and a subject-by-subject correlation with the BOLD signal in the amygdala. Our data dovetails well with the animal literature and sheds light on the neural control of vigor.

Figure - The PIT paradigm used. Stage 1, In the pavlovian conditioning stage, participants are exposed to repeated pairings of the CS+ (a visual background and a sound) and a US (monetary reward of 20 pence), as well as presentations of a CS– that is not associated with reward. Here participants pressed a key to remove a patch that hid either a coin (CS+) or a coin with a superimposed red X (CS–). During the baseline CS, no patches were present; thus, there was no opportunity for reward. Each CS block lasted 12 s. Stage 2, During instrumental learning, participants were trained to squeeze a handgrip to obtain the same reward. Each block lasted 12 s. Stage 3, The critical PIT test took place under extinction and included presentation of the three CSs in a random order (here only the CS+ block is depicted). The participant was allowed to continue responding instrumentally.

Figure - Amygdala activity associated with PIT. Participants who showed a larger global PIT expressed enhanced bilateral amygdala activation. The bar graph shows, for the right amygdala and NAcc, mean parameter estimates for the correlation, across participants, of global PIT with the parameter estimate in each CS condition. Error bars represent the 90% confidence interval. *p <>

There are No Moral Facts - Metzinger

Here is a brief essay from one of my heroes, Thomas Metzinger, that I completely agree with - spiced up by an unrelated and gratuitous graphic on morality.

I have become convinced that it would be of fundamental importance to know what a good state of consciousness is. Are there forms of subjective experience which — in a strictly normative sense — are better than others? Or worse? What states of consciousness should be illegal? What states of consciousness do we want to foster and cultivate and integrate into our societies? What states of consciousness can we force upon animals — for instance, in consciousness research itself? What states of consciousness do we want to show our children? And what state of consciousness do we eventually die in ourselves?

2007 has seen the rise of an important new discipline: "neuroethics". This is not simply a new branch of applied ethics for neuroscience — it raises deeper issues about selfhood, society and the image of man. Neuroscience is now quickly transformed into neurotechnology. I predict that parts of neurotechnology will turn into consciousness technology. In 2002, out-of-body experiences were, for the first time, induced with an electrode in the brain of an epileptic patient. In 2007 we saw the first two studies, published in Science, demonstrating how the conscious self can be transposed to a location outside of the physical body as experienced, non-invasively and in healthy subjects. Cognitive enhancers are on the rise. The conscious experience of will has been experimentally constructed and manipulated in a number of ways. Acute episodes of depression can be caused by direct interventions in the brain, and they have also been successfully blocked in previously treatment-resistant patients. And so on.

Whenever we understand the specific neural dynamics underlying a specific form of conscious content, we can in principle delete, amplify or modulate this content in our minds. So shouldn’t we have a new ethics of consciousness — one that does not ask what a good action is, but that goes directly to the heart of the matter, asks what we want to do with all this new knowledge and what the moral value of states of subjective experience is?

Here is where I have changed my mind. There are no moral facts. Moral sentences have no truth-values. The world itself is silent, it just doesn’t speak to us in normative affairs — nothing in the physical universe tells us what makes an action a good action or a specific brain-state a desirable one. Sure, we all would like to know what a good neurophenomenological configuration really is, and how we should optimize our conscious minds in the future. But it looks like, in a more rigorous and serious sense, there is just no ethical knowledge to be had. We are alone. And if that is true, all we have to go by are the contingent moral intuitions evolution has hard-wired into our emotional self-model. If we choose to simply go by what feels good, then our future is easy to predict: It will be primitive hedonism and organized religion.

Listening with your visual cortex.

We experience our environment through simultaneous stimulation of several sensory channels. Watching a movie is usually a visual and auditory experience. This integration from different sensory modalities helps with stimulus detection and discrimination in noisy environments. A traditional views of brain organization has postulated strict parceling into unisensory and and then multisensory cortical levels. Romei et al. have now shown in humans that auditory information goes directly to the primary visual cortex, before higher levels of integration.

When subjects are instructed to detect simple stimuli (a briefly presented pure tone, a small white disk, or a combination of the two), and their reaction times (RTs) are measured, reaction RTs are significantly better for the audio-visual (AV) condition than for both unimodal conditions, indicating a behavioral facilitation effect for stimuli presented simultaneously in both modalities. Romei et al. gave brief trans-cranial magnetic stimultion (TMS) to occipital poles of the subjects' heads. TMS effects over visual cortex in a timeframe from 60 to 75 ms after sensory stimulus onset would suggest an interaction with feedforward processes, whereas later effects might be caused by feedback from higher cortical regions. Thus, varying the delay from 30 to 150 ms between TMS and the preceding sensory stimulation in different sensory modalities enabled them to determine the processing type (feedforward or feedback), as well as the critical timeframe of visual cortex involvement in stimulus processing.

Relative to TMS over a control site, reactions times (RTs) to unisensory visual stimuli were prolonged by TMS at 60–75 ms poststimulus onset (visual suppression effect), confirming stimulation of functional visual cortex. Conversely, RTs to unisensory auditory stimuli were significantly shortened when visual cortex was stimulated by TMS at the same delays (beneficial interaction effect of auditory stimulation and occipital TMS). No TMS-effect on RTs was observed for AV stimulation. A follow-up experiment showed that auditory input enhances excitability within visual cortex itself over a similarly early time-window (75–120 ms).

Face perception after no experience of faces

This work really nails down the fact that face processing is a special perceptual process and is organized as such at birth, as contrasted with having its origin in a more general-purpose perceptual system that becomes specialized after frequent visual experiences. Sugita has studied face perception in monkeys reared with no exposure to faces. Here is his abstract, and one figure from the paper:

Infant monkeys were reared with no exposure to any faces for 6–24 months. Before being allowed to see a face, the monkeys showed a preference for human and monkey faces in photographs, and they discriminated human faces as well as monkey faces. After the deprivation period, the monkeys were exposed first to either human or monkey faces for a month. Soon after, the monkeys selectively discriminated the exposed species of face and showed a marked difficulty in regaining the ability to discriminate the other nonexposed species of face. These results indicate the existence of an experience-independent ability for face processing as well as an apparent sensitive period during which a broad but flexible face prototype develops into a concrete one for efficient processing of familiar faces.

Figure: An infant monkey and her living circumstance. An infant monkey and a caregiver with (A) and without (B) a facemask. Both photos were taken after the face-deprivation period. (C) Toys placed in the monkey's home cage. (D) Decorations provided around the home cage.