30/04/2010 by admin.

A good post in Frontal Cortex (here) talked about enculturation and how that inhibits new ideas, how we just don’t notice what it would be uncomfortable to notice because it would break our rules.

….There was a squirt of blood to the anterior cingulate cortex, a collar of tissue located in the center of the brain. The ACC is typically associated with the perception of errors and contradictions — neuroscientists often refer to it as part of the “Oh shit!” circuit — so it makes sense that it would be turned on when we watch a video of something that seems wrong….But there’s another region of the brain that can be activated as we go about editing reality. It’s called the dorsolateral prefrontal cortex, or DLPFC. It’s located just behind the forehead and is one of the last brain areas to develop in young adults. It plays a crucial role in suppressing so-called unwanted representations, getting rid of those thoughts that don’t square with our preconceptions.

When physics students saw the Aristotelian video with the aberrant balls, their DLPFCs kicked into gear and they quickly deleted the image from their consciousness. In most contexts, this act of editing is an essential cognitive skill. (When the DLPFC is damaged, people often struggle to pay attention, since they can’t filter out irrelevant stimuli.) However, when it comes to noticing anomalies, an efficient prefrontal cortex can actually be a serious liability. The DLPFC is constantly censoring the world, erasing facts from our experience. If the ACC is the “Oh shit!” circuit, the DLPFC is the Delete key. When the ACC and DLPFC “turn on together, people aren’t just noticing that something doesn’t look right,” Dunbar says. “They’re also inhibiting that information.”

This is a top-down erasing of sensory data. We have to process the image to understand what it is, then conclude that it is ‘impossible’, then eliminate the offending part from the image, all before the image is rendered conscious and we are aware of it. No spam in the conscious in-box – it makes life easier.

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27/04/2010 by admin.

I have been avoiding to a certain extent the nature of consciousness in some disease conditions. This is because I feel unqualified to say much about medical treatments of conditions I do not have myself. Here is an exception to my rule of thumb.

It is becoming clear that a number of mental conditions are caused by abnormal connections between areas of the brain. Other conditions may be caused by chemical imbalance, cell death and so on but now conductivity has to be added to the consideration of a wide range of conditions.

ScienceDaily had an item on how the disruption in brain connection is linked to the genetic defect in schizophrenia. (here)

…researchers at Columbia University Medical Center have illuminated how a genetic variant may lead to schizophrenia by causing a disruption in communication between the hippocampus and prefrontal cortex regions of the brain, areas believed to be responsible for carrying out working memory. Findings are published in the current online edition of Nature.

…”We now know that one of the consequences of that deletion (genetic marker found in many schizophrenics) is to disrupt functional communication between these two brain regions, and we have evidence from the study that the disruption actually has an impact on a cognitive behavior that is disrupted in patients, so it gives us a really strong indication of how the deletion can contribute to the development of schizophrenia. “It is possible that similar abnormalities in functional connectivity may also account for other symptoms of the disease, and can be used to better assess treatment response, and, most importantly, to develop new medications.”

As working memory is part of consciousness or closely associated with it, we can expect this connectivity fault to produce some of the abnormal consciousness found in schizophrenia.

Other looks at connection abnormalities and mental conditions are available. In a recent New Scientist article about deep brain stimulation (here) there is mention of the treatment of a number of conditions: Parkinsons, bipolar disorder, Tourette’s, obsessive compulsive disorder, and depression. The researchers into DBS treatment of depression theorize that what is being treated by the stimulation is problems with connectivity in neural networks.

My struggle to overcome dyslexia felt (from the inside) like attempts to form links between speech and phonemes and letters. I thought of them as alternative paths for the ones that seemed blocked.

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24/04/2010 by admin.

A recent paper, Unconscious Activation of the Prefrontal No-Go Network, by S Van Gaal and others, has results that may mean that I will have to revise my thinking. Unfortunately only the abstract (here) is available to me and so I have not been able to judge what this should do to my ideas.

Cognitive control processes involving prefrontal cortex allow humans to overrule and inhibit habitual responses to optimize performance in new and challenging situations, and traditional views hold that cognitive control is tightly linked with consciousness. We used functional magnetic resonance imaging to investigate to what extent unconscious “no-go” stimuli are capable of reaching cortical areas involved in inhibitory control, particularly the inferior frontal cortex (IFC) and the pre-supplementary motor area (pre-SMA). Participants performed a go/no-go task that included conscious (weakly masked) no-go trials, unconscious (strongly masked) no-go trials, as well as go trials. Replicating typical neuroimaging findings, response inhibition on conscious no-go stimuli was associated with a (mostly right-lateralized) frontoparietal “inhibition network.” Here, we demonstrate, however, that an unconscious no-go stimulus also can activate prefrontal control networks, most prominently the IFC and the pre-SMA. Moreover, if it does so, it brings about a substantial slowdown in the speed of responding, as if participants attempted to inhibit their response but just failed to withhold it completely. Interestingly, overall activation in this “unconscious inhibition network” correlated positively with the amount of slowdown triggered by unconscious no-go stimuli. In addition, neural differences between conscious and unconscious control are revealed. These results expand our understanding of the limits and depths of unconscious information processing in the human brain and demonstrate that prefrontal cognitive control functions are not exclusively influenced by conscious information.

What the authors seem to be saying, to my understanding, is that there are two no-go systems: conscious and unconscious. The conscious one actually works to stop an action. The unconscious one only slows the action and does not actually stop it.

If by conscious control, the authors mean control that we are conscious of, I find nothing disturbing. If by conscious control, they mean control that relies on a prior conscious process to come into existence, I find that very disturbing. If they are saying that a signal that is strong enough to stop an action will also be strong enough to enter our conscious awareness, then great. But I am not sure that this is what they mean. If they are saying that there are two paths and a signal enters the one or the other (for some unknown reason) and so it can either be conscious and successful in controlling action along the one path or it can be unconscious and only slow the action down on the other path, then I find it completely unconvincing.

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21/04/2010 by admin.

In the kitchen, a burning hot but fragile dish is dropped and someone catches it and therefore suffers a burn. They did not have time to think about whether this was a smart thing to do; they did it by reflex. But if they knew ahead of time that it was likely that a burning hot dish might fall and that if they caught it they would be burnt, then they can think about whether they want to catch the dish. And reflex or no – if they do not want the burn, they will not catch the plate. We can override many reflex actions but only if we do it ahead of the event that would trigger the reflex.

There are go/no-go situations where you have to commit to an particular action knowing that a very late signal may require you to stop the action in mid flow. Again is can only be done with fair warning. In order to do this the no-go signal has to be part of the planned program for the action.

Why is it so hard to count calories? Every time we are faced with food we have to exercise restraint, do a vague calculation and then use willpower to resist temptation. But if we have a severe allergy to a range of foods, we think about the effects of eating them. Very soon the dangerous foods become non-foods in our minds and we do not bother with them; they are not appetizing and tempting; practically no willpower at all is required to avoid them. It is actually easier to avoid certain foods all together then to cut down on consuming them. Again the key is rational thought about the consequence of actions BEFOREHAND.

Suppose it is important to be on good terms with someone you do not know very well. It would be a good idea to think for a little while about the consequences of what you might regret saying if you lose your temper or what the result might be of an inappropriate joke. Forearmed you can keep anger and humour in check. You are not going to see the dangers if you are unprepared when you begin to feel angry or when a very funny remark jumps up in your mind.

If I want to do something a particular way then I should make it a plan or a habit; then I am unlikely to do it any other way. But the plan or the habit has to be a rational, thought out one that is convincing to me. This is not magic or a shortcut, this is making good decisions ahead of time when I have the time and when I can see things in perceptive. But it is work all the same. It is part of what I call mind maintenance. If you try to make a pretend decision and ‘fool yourself’, it will not work. Decisions made ahead of time must be honestly and rationally made to be ready and useful when required.

Now I could rely on my willpower and my ability to make quick decisions when they are needed. I have known people who resist mind maintenance. They are proud of their willpower and look for situations to test it. When their willpower fails, as it always occasionally does, they feel that they have failed, punish themselves, and look for another test to prove that they have regained their great willpower. Willpower is a limited resource and we should be looking for ways of conserving it for emergencies not squandering it on silly mind game with ourselves.

Also there are people who resist mind maintenance because they take pleasure in spare of the moment decisions. It seems to validate their feeling that consciously made, quick decisions are proof of their free will. This is false - a decision is a decision. It can either be made by the brain or by magic. We cannot tell the difference by introspection. We have to infer how decisions are made from evidence. We can attempt to make them carefully or sloppily. I find it odd that there are people who risk sloppy decisions in order to feel, erroneously, that their decisions break the rules of the physical world. And what happens when we make a really bad decision, what springs into our minds is not that ‘oh well - that is what happens with free decisions’, it is ‘oh my - how am I going to avoid doing that again’. All the ‘if only I had…’ thoughts crowd the mind. So even if someone wants to believe in magically free decisions, they still should use that magic in a careful, rational way and make good decisions if they can and AHEAD OF TIME if possible.

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18/04/2010 by admin.

The Frontal Cortex blog had a posting (here) on dreaming.

The narratives that seem so incomprehensible — why was I running through the airport in my underwear? — are actually careful distillations of experience, a regurgitation of all the new ideas and insights we encounter during the day.

So what did J. Lehrer find in the literature? Memory consolidation:

While we’re fast asleep, the mind is sifting through the helter-skelter of the day, trying to figure out what we need to remember and what we can afford to forget.

Learning from experience:

(Matthew) Wilson speculates that dreams are also an attempt to search for associations between seemingly unrelated experiences, which is why it’s so important for the controlling conscious self to disappear. …How can we use the lessons of today …? This suggests that the strangeness of our nighttime narratives is actually an essential feature, as our memories are remixed and reshuffled, a mash-up tape made by the mind.

And insightful creativity:

R.E.M. sleep isn’t just essential for the formation of long-term memories: it might also be an essential component of creativity… (Jan) Born argues that deep sleep and dreaming “set the stage for the emergence of insight” by allowing us to mentally represent old ideas in new ways… According to (Sara) Mednick, the dramatic improvement in creativity is due to the fact that R.E.M. “primes associative networks,” allowing us to integrate new information into our problem-solving approach.

Dreams are very useful indeed for ordinary everyday life – remembering, learning and creating.

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15/04/2010 by admin.

Given their press, you would think that mirror neurons solved some great big problems with understanding the brain. But the fuss seemed to me to be premature. We do not need more ‘magic’ ideas; we need explanatory ones. Now it appears that mirror neurons may be part of a useful system.

Research Digest has a posting on research by R. Mukamel and group that uses recording from single cells in humans (here).

Most of the 1177 cells that were recorded showed a response either to the execution of an action or the sight of that action, not both. However, there was a significant subset of ‘mirror’ neurons in the front of the brain, including the supplementary motor area, and in the temporal lobe, including the hippocampus, that responded to the sight and execution of the very same actions.

So it seems humans do have them.

Critics could argue that rather than having mirror properties, these cells were responding to a concept. For example, according to this argument, a cell that responded to the sight of a smile and the execution of a smile, was actually being activated by the smile concept. Mukamel’s group reject that argument. They had a control condition in which the words for actions appeared on a screen, rather than those actions being seen or performed. The postulated mirror neurons responded to the sight and execution of an action, but not the word.

This logic implies that there are no non-verbal concepts. It is just a semantic quibble. We could call them pseudo-concepts or motor-cepts or the like. There is no reason that mirror neurons could not be responding to a motor action as if it were a concept, in a concept-ish sort of way.

Another potential criticism is that the execution-related activity of a postulated mirror neuron is triggered by the sight of one’s own action, rather than by motor-output per se. However, this can’t explain the mirror neurons that responded both to the sight of a given facial expression and one’s own execution of that facial expression (although proprioceptive feedback could still be a potential confound).

So it is not just a simple sensory identification of a motor act.

Mirror neurons make functional sense in relation to empathy and imitative learning, but a drawback could be unwanted imitation and confusion regarding ownership over actions. The researchers uncovered another subset of cells that could help reduce these risks - these cells were activated by the execution of a given movement but inhibited by the sight of someone else performing that same movement (or vice versa).

There appears to be quite a separate system for identifying the ownership of actions that does not necessarily include these cells. We do not need to postulate that mirror neurons are involved in that and if they are not involved, why would they confuse ownership. Research would have to be done to show if they were actually tied to the ownership identification.

‘Taken together,’ the researchers concluded, ‘these findings suggest the existence of multiple systems in the brain endowed with neural mirroring mechanisms for flexible integration and differentiation of the perceptual and motor aspects of actions performed by self and others.’

‘flexible integration and differentiation of the perceptual and motor aspects..’ of something sounds like definition of a concept to me.

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12/04/2010 by admin.

The Scientific American site had an article by M. Shermer on sensed presence effects. (here) He puts forward a list of possible causes:

Whatever the immediate cause of the sensed-presence effect, the deeper cause is to be found in the brain. I suggest four explanations: 1) The hallucination may be an extension of the normal sensed presence we experience of real people around us, perhaps triggered by isolation. 2) During oxygen deprivation, sleep deprivation or exhaustion, the rational cortical control over emotions shuts down, as in the fight-or-flight response, enabling inner voices and imaginary companions to arise. 3) The body schema, or our physical sense of self—believed to be located primarily in the temporal lobe of the left hemisphere—is the image of the body that the brain has constructed. If for any reason your brain is tricked into thinking that there is another you, it constructs a plausible explanation that this other you is actually another person—a sensed presence—nearby. 4) The mind schema, or our psychological sense of self, coordinates the many independent neural networks that simultaneously work away at problems in daily living so that we feel like a single mind.

Neuroscientist Michael S. Gazzaniga of the University of California, Santa Barbara, calls this the left-hemisphere interpreter—the brain’s storyteller that pulls together countless inputs into a meaningful narrative story. In an experiment with a “split-brain” patient (whose brain hemispheres were surgically disconnected), Gazzaniga presented the word “walk” only to the right hemisphere. The patient got up and began walking. When he was asked why, his left-hemisphere interpreter made up a story to explain this behavior: “I wanted to go get a Coke.”

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09/04/2010 by admin.

A. Cashmore has published an article, The Lucretian swerve: The biological basis of human behavior and the criminal justice system (here). His conclusion is:

I noted earlier that belief in what I refer to as the magic of the soul and Cartesian dualism has ostensibly disappeared. The emphasis that I now give to “ostensibly” reflects my belief that, in the absence of any molecular model accommodating the concept of free will, I have to conclude that the dualism of Descartes is alive and well. That is, just like Descartes, we still believe (much as we pretend otherwise) that there is a magic component to human behavior. Here I argue that the way we use the concept of free will is nonsensical. The beauty of the mind of man has nothing to do with free will or any unique hold that biology has on select laws of physics or chemistry… The reality is, not only do we have no more free will than a fly or a bacterium, in actuality we have no more free will than a bowl of sugar. The laws of nature are uniform throughout, and these laws do not accommodate the concept of free will. Some will argue that once we understand better the mechanistic details that underlie consciousness, then we will understand free will. Whatever the complexities of the molecular details of consciousness are, they are unlikely to involve any new law in physics that would break the causal laws of nature in a non-stochastic way…. any search for some new “Lucretian” law of physics, or some startlingly novel emergent principle, will not be successful.

Many believe that the consequences of a society lacking free will would be disastrous. In contrast, I argue that we do not necessarily need to be pessimistic about confronting a world lacking free will… Certainly, crime is a problem that society has much difficulty dealing with… surely it is inexcusable that in addressing these problems we continue to entertain this fallacious assumption discarded well over 100 years ago! It is my concern, that this vitalistic way of thinking about human behavior—a style of thinking that is present throughout our scientific institutions—serves only to hinder…. It is almost with a sense of pride that the authors of (biology) texts may contrast this understanding with the alternative earlier belief in vitalism—the belief that there are forces governing the biological world that are distinct from those that determine the physical world. The irony here is that in reality, a belief in free will is nothing less than a continuing belief in vitalism.

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06/04/2010 by admin.

The blog i09 has a posting by an unknown author, The Science (Fiction) of Embodied Cognition. (here). He asks how the projection of a personality or mind into an alien body would work in reality as opposed to science fiction stories like Avatar?

That’s what the science of “embodied cognition” is all about. The basic idea in this new(ish) research area (which overlaps with cognitive psychology, neuroscience, artificial intelligence, robotics, and others) is this: Your mind is defined by your physical form. Not just in terms of “the mind is what the brain does”-we all are pretty down with that already. This takes it further to encompass the whole enchilada: your mind-your “I”-is a function of a cephalized, bipedal, plantigrade, bilaterally symmetrical body between 1.5 and 2 meters tall with two arms terminating in five-fingered hands with opposable thumbs, two lungs, a warm-blooded vascular system, mostly hairless skin, two front-focused eyes, etc. etc. Change any aspects of that physical configuration-in subtle or radical ways-and the mind will inevitably change too….Your perceptions, actions and thoughts all feel direct, integrated, and grounded. You don’t “drive” your body, you ARE it. So why do we still assume that we might take that “little man” out and plop him into a different body to “look out of”, without any consequences? …. it does point the way toward a much more interesting angle on Avatar’s “going native” plotline. If you spent most of your waking hours embodied as a Na’Vi, how could you NOT be increasingly at risk of going native? Your essential psychological human-ness would inevitably drift and deform ….

At least most aliens we imagine are sort of humanoid – maybe we can’t imagine otherwise.

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03/04/2010 by admin.

Science Daily reports (here) on a paper in Nature Neuroscience, A central role for the lateral prefrontal cortex in goal-directed and stimulus-driven attention, by C. Asplund and group. They investigated being made temporarily blind by surprises.

“The simple example of having your reading interrupted by a fire alarm illustrates a fundamental aspect of attention: what ultimately reaches our awareness and guides our behavior depends on the interaction between goal-directed and stimulus-driven attention. For coherent behavior to emerge, you need these two forms of attention to be coordinated… We found a brain area, the inferior frontal junction, that may play a primary role in coordinating these two forms of attention.”

… the research team asked individuals to detect the letter “X” in a stream of letters appearing on a screen while their brain activity was being monitored using functional magnetic resonance imaging, or fMRI. Occasionally, an image of a face would unexpectedly interrupt the stream. The surprise caused the subject to completely miss the “X” the first couple of times, despite the fact they were staring directly at the part of the screen on which it appeared. They were eventually able to identify it as successfully as when there was no surprise. …the inferior frontal junction, a region of the lateral prefrontal cortex, was involved in both the original task and in the reaction to the surprise.

“What we think might be happening is that this brain area is coordinating different attention systems — it has a response both when you are controlling your attention and when you feel as though your attention is jerked away.”

“What we show is the dark side or negative impact of the orienting response. We found it blinds you to other events that can occur soon after the presentation of the surprise stimulus.,” The researchers hypothesize that we may be temporarily blinded by surprise because the surprise stimulus and subsequent response occupies so much of our processing ability. “The idea is that we can’t attend to everything at once. It seems that the inferior frontal junction is involved in this limitation in attention.”

The new research supports previous work by Marois’ laboratory that found the interior frontal junction plays the role of an attentional bottleneck — limiting our ability to multitask and attend to many things at once.

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