23/05/2012 by admin.

That fringe feeling we get that we should be wary, suspicion, rises into consciousness from time to time – but where does it come from?

A recent item in ScienceDaily (here) reports on a paper by Bhatt, Lohrenz, Camerer and Montague, Distinct contributions of the amygdala and parahippocampal gyrus to suspicion in a repeated bargaining game. They separate two types of suspicion.

“We found a strong correlation between the amygdala and a baseline level of distrust, which may be based on a person’s beliefs about the trustworthiness of other people in general, his or her emotional state, and the situation at hand. What surprised us, though, is that when other people’s behavior aroused suspicion, the parahippocampal gyrus lit up, acting like an inborn lie detector.”

One way to think of this is that there is a default level of wariness set by the amygdala. It is on a spectrum from being trusting as a default to being suspicious as a default for each individual and would also change with the danger of the situation and the day to day level of confidence of the individual. The parahippocampal gyrus on the other hand reacts to the probability that a particular person is untrustworthy.

So, the fringe feeling of wariness comes from the amygdala but the attribute of untrustworthiness associated with a specific individual comes from the parahippocampal gyrus.

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20/05/2012 by admin.

A method called fMRI-adaptation has been used to show a neural population that is activated by whole individuals rather than just faces or bodies. The fMRI-A effect depends on the adaptation or attenuation of the BOLD signal because of the repetition of a specific stimulus in a neural population that is sensitive to that particular stimulus.

So far fMRI-A has been used to characterize the representations underlying neural responses to a number of visual stimulus classes including faces, headless bodies, objects, scenes, as well as more generally to the binding of objects and background scenes and to the coding of objects presented in peripersonal space.

Schmalzl, Zopf, and Williams have recently published a paper (see citation below) in which they use fMRI-A to investigate the neural populations that show selective adaptation to the visual presentation of whole individuals, as opposed to just isolated faces or bodies.

In the fusiform gyrus and extrastriate regions, they found areas of specific adaptation effects for same faces, same bodies, either same faces or same bodies, same whole individuals, whole individuals whether same or different (individual category classification).

While the existence of voxels that show significant adaptation only when both the same face and the same body are presented points into the direction of response selectivity for whole individuals, it cannot be taken as evidence for it. The adaptation effect for whole individuals could be merely additive, namely a sum of face and body specific responses. That is, it could simply reflect the fact that some voxels contain a mixture of face and body selective neurons whose individual category specific response is not strong enough to yield significant adaptation, but whose combined response is. We therefore took our analysis one step further and defined a superadditive contrast for the SFSB (same face same body) condition. Specifically, we defined a new independent contrast that allowed us to investigate whether for some voxels showing significant SFSB adaptation, this adaptation was actually larger than the sum of the adaptation shown for all other conditions.

Here is their abstract:

Our ability to recognize other people’s faces and bodies is crucial for our social interactions. Previous neuroimaging studies have repeatedly demonstrated the existence of brain areas that selectively respond to visually presented faces and bodies. In daily life, however, we see “whole” people and not just isolated faces and bodies, and the question remains of how information from these two categories of stimuli is integrated at a neural level. Are faces and bodies merely processed independently, or are there neural populations that actually code for whole individuals? In the current study we addressed this question using a functional magnetic resonance imaging adaptation paradigm involving the sequential presentation of visual stimuli depicting whole individuals. It is known that adaptation effects for a component of a stimulus only occur in neural populations that are sensitive to that particular component. The design of our experiment allowed us to measure adaptation effects occurring when either just the face, just the body, or both the face and the body of an individual were repeated. Crucially, we found novel evidence for the existence of neural populations in fusiform as well as extrastriate regions that showed selective adaptation for whole individuals, which could not be merely explained by the sum of adaptation for face and body respectively. The functional specificity of these neural populations is likely to support fast and accurate recognition and integration of information conveyed by both faces and bodies. Hence, they can be assumed to play an important role for identity as well as emotion recognition in everyday life.

Schmalzl, L., Zopf, R., & Williams, M. (2012). From Head to Toe: Evidence for Selective Brain Activation Reflecting Visual Perception of Whole Individuals Frontiers in Human Neuroscience, 6 DOI: 10.3389/fnhum.2012.00108

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17/05/2012 by admin.

Mind-pops are those little thoughts, words, images or tunes that suddenly pop into your mind at unexpected times and are totally unrelated to your current activity. A recent paper showed that mind-pops were more common in schizophrenics than others. (here) That is not what I want to talk about, it just started me thinking about mind-pops – those I or my friends have. What can prompt mind-pops normally?

I view them as part of a normal effect. I’m talking to someone and I suddenly cannot remember the name of the actor in the program I am describing. I consciously ask to myself what that name is and a few minutes later, after the conversation has gone on to something else, the actor’s name pops into my head. I have no doubt about why it ‘popped’ – a process was started to find the name, it took some time, but now it is returning the result. If it ‘popped’ two days later, I might or might not make the connection. If it ‘popped’ two weeks later, I might be puzzled by why that name suddenly appeared in my consciousness.

For many years, I have assumed that there was always a reason, a mind-pop was an answer to a problem of some sort that has been solved unconsciously. It need not be a memory recall problem but often is. We do not know consciously all of the problems that we are currently tackling unconsciously. Many may never have been registered consciously.

Schizophrenics have difficulties with many aspects of thought so it is not surprising that they may have more or even different sorts of mind-pops. This does not mean they are unnatural for the rest of us, or worrisome. They may just be the answer to a problem that we have just, finally, solved.

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14/05/2012 by admin.

New products have teething problems, development bugs; they need beta development, shaking down before they are reliable. We can presume that this may also be true of the evolution of new species. The great innovations come with side-effects. I have encountered people who said this about our chronic back pains being a side-effect of upright walking. It is a great thing but may have a couple of weak spots. We would actually be surprised if evolution didn’t take some time in a shake down of a new species.

A recent paper in Cell by 20 authors (this was really a big international effort) has tackled the question of whether autism is the unfortunate result of the malfunctioning of a relatively new aspect of the human brain. The essence of the paper is given in a press release from Yale:

(the team) identified the evolutionary changes that led the NOS1 gene to become active specifically in the parts of the developing human brain that form the adult centers for speech and language and decision-making. This pattern of NOS1 activity is controlled by a protein called FMRP and is missing in Fragile X syndrome, a disorder caused by a genetic defect on the X chromosome that disrupts FMRP production. Fragile X syndrome, the leading inherited form of intellectual disability, is also the most common single-gene cause of autism. The loss of NOS1 activity may contribute to some of the many cognitive deficits suffered by those with Fragile X syndrome, such as lower IQ, attention deficits, and speech and language delays … it is a more recent evolutionary adaptation possibly involved in the wiring of neural circuits important for higher cognitive abilities. The findings of the Cell paper support this hypothesis. The study also provides insights into how genetic deficits in early development, a time when brain circuits are formed, can lead to disorders such as autism, in which symptoms appear after birth.

There are a couple of aspects that should be brought up in context of this research. First, this is unlikely to be the only cause of autism. Autism is defined as a set of symptoms (and a not too clearly specified set with arbitrary measures – not a yes/no blood test or the like). A number of causes could end up with similar symptoms. Even a number of genetic causes could end up with the same end result.

Second, when the NOS1 activity is disrupted, the brain will not simply step back to a previous version of the homo brain. We should not make the mistake of assuming that our ancestors resembled people with autism. It may be that the functions that were replaced by the products of NOS1 are no longer available.

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11/05/2012 by admin.

There has recently been a review of the relationship between conscious and unconscious processing by van Gaal and others. (Citation below) They looked at an area of common misunderstanding and attempted to clarify it. Here are the highlights of their summarizing discussion:

… we have reviewed recent studies that have focused on the complexity and strength of unconscious information processing in relation to cognitive control (e.g., response inhibition, conflict resolution, and task-switching), the life-time of information maintenance (e.g., working memory, recognition memory) and the possibility to integrate multiple pieces of information across space and time. Unconscious information has been shown to affect various perceptual and high-level cognitive functions and the associated brain areas, including prefrontal cortex. In some cases, unconscious information has been observed to affect behavior and brain activity for relatively long periods of time. Overall, these recent results highlight the power of unconscious information processing, going beyond specific expectations formulated in traditional theoretical models of consciousness and the cognitive functions thought to require consciousness. … one can conclude that the potential function of consciousness might not be related to the initiation of cognitive control functions by specific stimuli that signal the need for increased control (e.g., stop-signals, task-switching cues). These cognitive control operations are probably triggered by a fast feedforward, and unconscious, early sweep of information processing that reaches even regions in the prefrontal cortex. This unconscious fast feedforward sweep can directly affect (the speed of) ongoing cognitive processes. … Although recent evidence has clearly pushed the boundaries regarding the duration of unconscious effects, the general observation is that unconscious events are much less able to elicit (long-term) future behavioral adaptations than conscious events (e.g., post-error slowing, conflict adaptation). Why might this be the case? Theoretical models of consciousness suggest that conscious awareness is related to long-lasting recurrent interactions between (distant) brain regions. This might enable the exchange of information between several spatially separated cognitive modules, which seems to break the automaticity of information processing. Awareness might be beneficial for enabling flexible and durable information processing strategies that are not directly triggered by a specific stimulus, for example when information has to be integrated across longer periods of time to bias information acquisition or signal the need for performance adjustments . Recently, Kunde et al. suggested that awareness might be dispensable when cognitive control is signaled explicitly (by specific control-eliciting stimuli) but not when it has to be inferred implicitly (by the context, or history of events).

van Gaal, S., de Lange, F., & Cohen, M. (2012). The role of consciousness in cognitive control and decision making Frontiers in Human Neuroscience, 6 DOI: 10.3389/fnhum.2012.00121

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08/05/2012 by admin.

For the majority of us, the characteristics of things stay within their sensory categories. We do not see numbers with colours; we do not feel sounds; we do not taste shapes. People who have these strange mixing of the senses, synesthetes, are not that rare. For a long time, the idea of synesthesia was not accepted. Now, it has been shown over and over to be a real way of perceiving, individual to the person but stable and automatic.

Recently a few people have been found that see colour in response to various emotions. Ramachandran studied a man with this type of synesthesia. He saw a blue aura around a person which changes shade when particular emotions were sensed. The researchers placed a target person against a white background and drew a black line on the background around the person. The subject saw the blue aura in the space between the person and the black line. Blue or orange letters were projected onto the background and the subjects was timed in his identification of the letters. Blue letters inside the black line were identified slower than orange letters or blue letters outside the line. Blue letters against blue aura were more difficult to see. The researchers will be looking for cross-activation of V4 colour perception area and other areas (they hypothesis insular cortex, activated during subjective experience of emotion).

A Spanish group under Milan studied healers. One healer in particular, with a very good reputation, was clearly a face-colour synesthete seeing the aura of people, a touch-mirror synesthete who experience touch and pain when seeing it happen to someone else, and also a schizotypy personality tending towards slight paranoia and delusions. The researchers believed that the synesthesia encouraged the healers to believe in their own ability to heal other people, and their confidence caused a significant placebo effect in the healed people. However they believe that synesthesia is not an extrasensory power but a subjective and adorned perception of reality.

Oh well, educated people used to believe that meteorites and ball lightening were silly tales of the ignorant and superstitious. Now we are finding that near death experiences, ghosts and auras may have reasonable explanations and are not faked but simply not understood.

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05/05/2012 by admin.

If we look at how communication works we find that words and phrases have a great influence on attention. They bring into the consciousness of the listener the concepts that are uttered. This is what meaning is – the concepts that a word or phrase can steer attention towards. This is what communication is – the sharing of attention by two (or more) brains on a sequence of concepts.

So it is not surprising that it is useful to talk to oneself. What we are doing when we self-talk is to steer our consciousness. In recent paper (see citation below), Lupyan and Swingley look at how self-directed speech affects searching. Here is part of their conclusions:

In this work, we examined effects of self-directed speech on performance on a simple visual task. Speaking the name of the object for which one was searching affected performance on the visual search task relative to intermixed trials on which participants read the word but did not actually speak it before or during search. The effect of speaking depended strongly on the characteristics of the target item. Search was improved for the most familiar and prototypical items - those for which speaking the name is hypothesized to evoke the visual representation that best matches the visual characteristics of the target item. Search was unaffected or impaired as the discrepancy between the name and target - measured by measures of familiarity and imagery concordance - was increased.

Facilitation due to speaking also became larger with repeated exposures to the target items. Arguably this occurred because multiple exposures strengthened the associations between the label (e.g., “elephant”) and the visual exemplar (a given picture of an elephant). The idea that saying a category name activates a more prototypical representation of the category is also supported by the finding that speaking the name actually hurts performance for items with low within-category similarity. One implication is that repeating the word “knife” may, for example, help an airport baggage screener spot typical knives, but actually make it more difficult to find less prototypical knives.

On our view, the reason speaking the target name affects visual search performance is that speaking its name helps to activate and/or keep active visual (as well as nonvisual) features that are diagnostic of the object’s category, facilitating the processing of objects with representations overlapping those activated by the label. This activation of visual features occurs during silent reading as well. Indeed, it is what allows fore-knowledge of the target to guide search. Self-directed speech, as implemented in the present studies, is hypothesized to further enhance this process.

This idea of controlling attention is also shown when people try to keep some piece of information in working memory by repeating it, when they encourage themselves to do something difficult or scaring, when they are learning (or planning) a complex sequence of actions. Searching is not the only activity that benefits from a little talking to yourself.

Lupyan, G., & Swingley, D. (2011). Self-directed speech affects visual search performance The Quarterly Journal of Experimental Psychology, 1-18 DOI: 10.1080/17470218.2011.647039

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02/05/2012 by admin.

Malcolm MacIver has a posting in the Discovery Blog, Science not Fiction. (here) He connects consciousness with the evolution from marine animals to land animals. His argument goes: (1) marine animals cannot see far compared to their speed (2) therefore marine animals can only react quickly to what they sense (3) moving to land increased their ‘perceptual horizon’ 10,000 fold (4) therefore land animals had time to plan their actions rather than simply react (5) planning needs consciousness.

This puts the first such members of the “buena vista sensing club” into a very interesting position, from an evolutionary perspective. Think of the first animal that gains whatever mutation it might take to disconnect sensory input from motor output (before this point, their rapid linkage was necessary because of the need for reactivity to avoid becoming lunch). At this point, they can potentially survey multiple possible futures and pick the one most likely to lead to success. For example, rather than go straight for the gazelle and risk disclosing your position too soon, you may choose to stalk slowly along a line of bushes (wary that your future dinner is also seeing 10,000 times better than its watery ancestors) until you are much closer.

I am not sure I buy this picture, although it could be behind a big step up in consciousness. One problem is that the theory depends heavily on vision being the main sense. Cetacea (dophins, whales) were land animals that returned to the sea. They did not lose their consciousness but used their hearing as their main sense rather than sight. Their perceptual horizons may be as long or longer than ours. Marine animals use tactile sensing of water movements and electrical sensing as well. One would have to look at the perceptual horizon available from all senses to make a tight argument for the buena vista theory.

There is also the Cephalopods (octopus, squid, cuttlefish) which have never been on land but appear to have no problem with planning and the like. They would not have a same sort of consciousness as vertebrates but it is not a given that they lack a very similar function.

On the other hand, consciousness is costly and slower than reflex so it is not likely to be elaborated in environments where it does not give a yield greater than its cost. Read the post for some interesting crystal ball looks as well as the fuller explanation of the theory.

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29/04/2012 by admin.

“What exactly is beauty?”, is an old and unanswered question. It is one of those fringe qualia of consciousness – not a perception but a feeling, like familiarity or certainty, which is attached to a perception. But the criteria for this feeling has never been settled. A recent paper by Ishizu and Zeti (citation below) looks for the traces of beauty in the brain. Here is the abstract:

We wanted to learn whether activity in the same area(s) of the brain correlate with the experience of beauty derived from different sources. 21 subjects took part in a brain-scanning experiment using functional magnetic resonance imaging. Prior to the experiment, they viewed pictures of paintings and listened to musical excerpts, both of which they rated on a scale of 1–9, with 9 being the most beautiful. This allowed us to select three sets of stimuli–beautiful, indifferent and ugly–which subjects viewed and heard in the scanner, and rated at the end of each presentation. The results of a conjunction analysis of brain activity showed that, of the several areas that were active with each type of stimulus, only one cortical area, located in the medial orbito-frontal cortex (mOFC), was active during the experience of musical and visual beauty, with the activity produced by the experience of beauty derived from either source overlapping almost completely within it. The strength of activation in this part of the mOFC was proportional to the strength of the declared intensity of the experience of beauty. We conclude that, as far as activity in the brain is concerned, there is a faculty of beauty that is not dependent on the modality through which it is conveyed but which can be activated by at least two sources–musical and visual–and probably by other sources as well. This has led us to formulate a brain-based theory of beauty.

Of course, there are many other areas of the brain involved in beauty but none with the overlap of vision and hearing found in the A1 part of the orbito-frontal cortex. They give a specific location to their area A1 as a reference for other researchers. This seems to be the seat of an abstract sense of beauty. Facial attractiveness activates A1 or very nearby. This is also in the general area associated with pleasure, reward, desire, value evaluation and judgments. The visual and auditory activity in A1 have a different onset after stimulus and so probably do not follow the same path from some other shared area but arrive independently, musical before visual beauty.

The caudate nucleus also is activated with an intensity matching experience of beauty but only for visual not auditory stimuli. This area has been associated with romantic love.

We might expect that if beauty has an abstract area of activation than ugliness would too. Not so, there seems no overlap of visual and auditory ugliness. Ugliness appears tied to particular sorts of ugliness, not a symmetrical opposite of abstract beauty. It is perhaps an emotional reaction involving fear, disgust or similar.

We did not find activity in A1 of mOFC that correlates positively with the experience of ugly stimuli, although ugliness, too, involves a judgment. Instead, the parametrically modulated activity with the experience of ugliness was confined to the amygdala and left somato-motor cortex. This implies that there may be a functional specialization within the brain for at least two different kinds of judgment, those related to positive, rewarding, experiences and those related to negative ones.

Beauty has a specific neural correlate. Its activation probably depends on the individual, the object and the situation. It is a value judgement in the broadest sense, a positive judgement based on pleasure, desire and reward.

Ishizu, T., & Zeki, S. (2011). Toward A Brain-Based Theory of Beauty PLoS ONE, 6 (7) DOI: 10.1371/journal.pone.0021852

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26/04/2012 by admin.

I have been interested in communication for many years. Not written stuff but oral speech and accompanying non-verbal communication. How is it that we manage a link, a synchrony, a shared perception between two minds.

A recent blog posting in the Scientific American has some interesting things to say about movies, similar to what has been said about stage magic. There are ways to affect the audience and are skilled practitioners of these arts. Here is the link to Maria Konninova’s posting, The Innate Irresistibility of Film.

Of course we start out with a perceptual slight of hand. The movie is discrete frames but we see it as a continuous. This is because the frames per second is close to the natural ‘frames’ of consciousness which is also discrete. Konninova also mentions the control of blinks, eye movements and event breaks.

… researchers are finally beginning to understand what it is that makes the present-day film experience so binding on a profound level - and why it’s often difficult for older movies to keep up. It seems that filmmakers have over the years perfected the way to best capture - and keep - viewers’ attention. Through trial, error, and instinct, Hollywood has figured out how best to cater to the natural dynamic of our attention and how to capitalize on our naïve assumptions about the continuity of space, time, and action.

… blink synchronicity: if we see someone blink, we’ll likely blink right along with him. Film editor Walter Murch noticed that very thing when he was editing Francis Ford Coppola’s The Conversation. When Gene Hackman blinked, there went Murch’s eyes—and that’s precisely where he wanted to place the film cut. Cut at the blinks, and more likely than not, the viewers will perceive the action as continuous. The cut itself will go unnoticed. … People who view the same film tend to synchronize their blinks – and that synchronization reflects the editing of the story. …

When people watch a movie, their eyes tend to follow similar patterns. Even if a scene has no actors, it remains likely that gaze focus will follow the same trajectory between different viewers. And it’s not just the gaze: each viewer’s brain may actually be reacting in similar fashion as well.

In one study, individuals watched the first 30 minutes of The Good, The Bad and the Ugly while their brains were scanned by fMRI. Researchers found that 45% of neocortical activity—including areas implicated in vision, hearing, emotion, language, and multisensory integration—was quite similar for each viewer. That’s almost half the activity of that part of our brain that coordinates our higher cognitive functions. Impressive indeed.

… When people viewed The Red Balloon in a scanner and then divided the film into events, cuts that coincided with significant changes in action predictably activated dorsal frontal and medial temporal areas of the brain—associated with attentional control and motion processing, respectively—in a similar fashion for each viewer.

In the same way that we could learn much about attention from magicians, we could learn much about consciousness from movie editors. Back to the subject of communication, we can also learn from ordinary conversations. It seems that people who are busy talking seem to get on the same wave length. They synchronize their movements and posture, they get a rhythm going in the speech, their mimic each other’s face expressions, they blink together. Hey, they are coordinating their consciousness.

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