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Archive for the ‘consciousness’ Category

Picture 1Here is a heads up for a recent study demonstrating – again – that the amygdala is not merely a “fear centre” in the brain. I have previously blogged about the amygdala, first not being a single structure, and that it is not only involved in fear.

In 2007, a team of French researchers demonstrated that direct stimulation of the amygdala did evoke emotional responses, but that there was a difference between which hemisphere was stimulated. Right amygdala stimulations induced aversive responses, in particular fear and sadness. In contrast, left hemisphere stimulation induced either positive (happiness) or negative emotions (fear, anxiety, sadness). As the abstract reads:

Very few studies in humans have quantified the effect obtained after direct electrical stimulation of the amygdala, in terms of both emotional and physiological responses. We tested patients with drug-resistant partial epilepsies who were explored with intracerebral electrodes in the setting of presurgical evaluation. We assessed the effects of direct electric stimulations in either the right or the left amygdala on verbally self-reported emotions (Izard scale) and on psychophysiological markers of emotions by recording skin conductance responses (SCRs) and by measuring the electromyographic responses of the corrugator supercilii (EMGc). According to responses on Izard scales, electrical stimulations of the right amygdala induced negative emotions, especially fear and sadness. In contrast, stimulations of the left amygdala were able to induce either pleasant (happiness) or unpleasant (fear, anxiety, sadness) emotions. Unpleasant states induced by electrical stimulations were accompanied by an increase in EMGc activity. In addition, when emotional changes were reported after electrical stimulation, SCR amplitude for the positively valenced emotions was larger than for the negative ones. These findings provide direct in vivo evidence that the human amygdala is involved in emotional experiences and strengthen the hypothesis of a functional asymmetry of the amygdala for valence and arousal processing.

Interestingly, there is more to say about this study. First, it may be that there is a systematic bias introduced by the way the researchers did the study. By using high-frequency (50 Hz) stimulation in 1 second, they might have induced one characteristic response of the amygdala. This structure is often seen as having quick “on-off” responses. Thus, one second pulse trains is actually a long duration for the amygdala. So a pulse of 20 milliseconds could be hypothesised to produce different responses. Also, the researchers found that GSR responses were actually larger for positive emotions, when they were reported. As the amygdala has often been implicated in unconscious emotional responses (mostly aversive responses) one may speculate that the left-hemisphere amygdala involvement in positive emotions may be related to conscious emotions.

As always, new findings leads to numerous novel questions, ideas and hypotheses. Which is why science is so much fun. But it is important to note the change we see today the role of the amygdala in emotional responses. We are moving away from the LeDouxian paradigmatic focus on fear (and some aversion)as the sole emotion of the brain, and more towards a balanced view towards a similar focus on positive emotions and (hopefully) more complex human emotions. Through this development, we can see that novel findings are breaking down the old ideas of neo-phrenology, breaking single structures into smaller parts, and into parts of a larger network of convergence and divergence structures. Keep your eyes open, more is on the way.

-Thomas

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Just noticed this very attractive title by the Brafman brothers- The book, Sway — the irresistable pull of irrational behavior, “will challenge your every thought”, according to a NY Times review. And it gets similarly good reviews from other prominent people, like Michael Shermer, the author of the recent book The mind of the market, which I blogged about recently.

I found a couple of good videos on this book that’s good to share:

A longer version with more nuances can be seen here:

So after this, you get the idea: unconscious, automatic thought patterns act out and cause irrational behaviours, sometimes at the worst possible time and place.The questions raised are, of course, interesting and important. Why do we sometimes make horrific decisions, despite having all the information available to make better ones? Why do prominent people, like George W. Bush, suffer from loss aversion, leading to billions of dollars spent and thousands of lives lost? Because it’s “too late” to pull out? Because the pain of acknowledging defeat, error or insufficiency is bigger than the benefit of sparing yet more money and lives?

Other examples can be found at the Wall Street, military, aircraft captains, and even yourself. Maybe even on a daily basis. Taken together, the examples presented in these videos and the book demonstrate that we are all susceptible to make these kinds of errors. The next and better step is, of course, to identify these errors in ourselves (and others) and act upon them in time. Coaching, anyone?

I guess I should read the book, if the publishers will send me the book 8)

-Thomas

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Here is a heads up for the upcoming Sedbergh Festival of Ideas. Martin is going over to bring our view on the neuroethics of consciousness science research. Unfortunately, I’m unable to attend, but Martin will cover our ideas very nicely.

The event Martin is talking at is “Event 4 — Varieties of consciousness“, together wih no other than Geraint Rees, Ilona Roth and Max Velmans. If you are in the vicinity, why not attend? I hope Martin is going to blog about this meeting, just as he will with his recent trip to the HBM conference.

UPDATE: Here is the program (I just received from Andi Chapple):

Session 1 – Science and Consciousness
10am – 1.30pm, Saturday 19 July
People’s Hall, Howgill Lane, Sedbergh, Cumbria LA10 5DE, England
£15 (£6 concessions) for the whole session, £6 (£2.50 concessions) for the discussion (introduced and moderated by Prof. Velmans) from 11.45am to 1.30pm.

Professor Geraint Rees, Institute of Cognitive Neuroscience, UCL, London
Dr. Ilona Roth, Psychology in Science Group, Open University
Martin Skov, Danish Research Centre for Magnetic Resonance, Copenhagen
Professor Max Velmans, Goldsmiths College, London

Professor Tom Ormerod, University of Lancaster introduces the speakers.

Session 2 – Varieties of Consciousness
10am – 1.30pm, Sunday 20 July
People’s Hall, Howgill Lane, Sedbergh, Cumbria LA10 5DE, England
£12 (£5 concessions)

Speakers will lead short hands-on sessions so the audience can get personal experience of what they are talking about, then present their area of interest, and then there will be a general discussion.

Dr. Michael Daniels, Liverpool John Moores University (transpersonal
psychology and parapsychology)

Dr. David Scott (Zen and ‘Big Mind’ techniques)
Ian McPherson (t’ai chi and qi gong)

-Thomas

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hjernep1grafik620×120_istoc.jpg

And while we’re in the talk of media coverage, I should mention to those who understand Danish that the Danish Broadcast Company, or DR, has a documentary series on their primary radio channels, P1. The series is called “Hjernerejsen” (loosely translated to “The brain travel”) and it covers topics such as emotions and bonding, brain maturation, transhumanism and neuroethics.In the program called “the soul is in the brain”, I starred in an interview about the new ideas that neuroscience brings to our traditional thoughts about personality and self. My co-interviewees were Jesper Mogensen and Albert Gjedde, both well-renowned neuroscientists both within and outside Scandinavia.

In a coming topic on the senses (tomorrow, April 19.), I speak about how neuroscience can be used in marketing, aka neuromarketing.

The series can be found here, and DR does a nice podcast: http://podcast.dr.dk/p1/rssfeed/tema_torsdag.xml (copy and paste into your preferred podcasting program)

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books.jpgWhile Thomas is getting his kicks off at the SfN meeting in Atlanta I am toiling away at a number of long overdue papers here in the increasingly cold Denmark. I have several longer blog posts planned, but no time to write them. So, here’s three things to read in the meantime at other venues on the net.

First, John Searle reviews a new book on consciousness by Nicholas Humphrey, Seeing Red, in The New York Review of Books. I have always enjoyed Humphrey’s work, but his new theory on consciousness sounds plain weird (at least as retold by Searle; I haven’t read Humphrey’s book). In Searle’s words:

(more…)

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scr11_new.pngThis time it should work. Science & Consciousness Review, the online webzine/journal for the review of the scientific study of consciousness, is back online. It crashed several months ago due to a buggy new interface and content management system. Now, with a fresh new and well proved system (same as BrainEthics is using, wordpress), it is now running, albeit in a next-to-full version. Commenting is still disabled, as are newsletters, certain images and some other functions. It’s slowly coming up, too
However, you can now enjoy the articles that we at BrainEthics have contributed with at SCR. First of all, Martin’s excellent review of Solso’s book on neuroaesthetics, and my article on “how genes make up your mind”.

Enjoy… and spread the word.

-Thomas

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A conscious veggie?

lockedin.jpgIt should be mentioned that there is a highly controversial paper out in this week’s Science. Here, a study by Dr Adrian Owen shows that a patient that meets the criteria for vegetative state shows what can be thought of as signs of conscious life. You can see the MindHacks coverage of this story here. basically, the researchers asked their patient to imagine playing tennis or moving around her home and found that:

the patient activated predicted cortical areas in a manner indistinguishable from that of healthy volunteers

The researchers take this as a sign of the patient being conscious while still being unable to communicate, let alone perform any volutary behaviour. In this sense, it seems that the patient rather meets the criteria for locked-in syndrome. The study thus raises the question of whether this patient — indeed, any PVS patient — is conscious, and whether the diagnostic criteria are yet poorly defined and the symptoms similarly poorly understood.

Nevertheless, it should be considered an open question whether we should accept this finding as a true sign of consciousness in the patient. This is also covered nicely in a comment by Naccache in the same issue of Science. Pointing out some of the shortcomings of this study, as well as contrasting it to the many studies showing specific changes in PVS contrasted to normal consciousness, Naccache concludes:

Though not totally convincing on the issue of consciousness, the Owen et al. work paves the way for future functional brain-imaging studies on comatose and vegetative state patients. One can imagine probing each of the psychological properties of conscious processing listed above, and even trying to collect subjective reports by modifying the experimental paradigm.

As I have written earlier, this is indeed the case: we do not have a clear concept of the distinctions between coma, vegetative states, minimally conscious states or locked-in syndrome. Only during the past few years we have seen a dramatic increase in our understanding of these disorders. It is no doubt that our understanding will increase in the same manner during the next many years.

I have asked Dr. Owen and his co-author, Steven Laureys about this finding, and hope to get back to you with their replies shortly. In the meantime, you might be interested in this article (PDF) that Laureys and I co-authored with prof. Bernard Baars in TINS.

UPDATE: Nature has a podcast interview with Dr. Owen here.

-Thomas

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In an interesting paper in the latest version of Progress in Neurobiology, Yuri I. Arshavsky from UCSD writes about the epistemological dualism that exists in modern neuroscience. basically, Arshavsky claims that there is a covert dualism in the way that neuroscientists are treating mind-related topics, especially the study of “consciousness”. Indeed, as he claims:

This covert dualism seems to be rooted in the main paradigm of neuroscience that suggests that cognitive functions, such as language production and comprehension, face recognition, declarative memory, emotions, etc., are performed by neural networks consisting of simple elements.

This might initially sound a bit strange. Is not cognitive functions such as face perception due to operational simple elements? Face perception as such is a combination of many simple processes that operate in unison. So what is Arshavsky proposing? Indeed he suggests the existence of a certain kind of brain cells:

(The) performance of cognitive functions is based on complex cooperative activity of “complex” neurons that are carriers of “elementary cognition.” The uniqueness of human cognitive functions, which has a genetic basis, is determined by the specificity of genes expressed by these “complex” neurons. The main goal of the review is to show that the identification of the genes implicated in cognitive functions and the understanding of a functional role of their products is a possible way to overcome covert dualism in neuroscience.

So there should exist a subset of neurons that integrate information from a variety of input. This sounds strange, since all neurons integrate inputs from thousands of inputs, many from a large variety of inputs. So what are complex neurons? Here, we are told that:

(…) neural networks involved in performing cognitive functions are formed not by simple neurons whose function is limited to the generation of electrical potentials and transmission of signals to other neurons, but by complex neurons that can be regarded as carriers of “elementary” cognition. The performance of cognitive functions is based on the cooperative activity of this type of complex neurons.

In this way, complex neurons seem to be integrative neurons, i.e. cells that integrate information from a variety of processes. This could include the multi-modal neurons found in the functional sub-structures of the medial temporal lobe, such as the hippocampus, perirhinal, entorhinal and temporopolar cortex. But would it not mean the colour processing nodes in the visual cortex? Which IMO leads us back to a basic question: what is a functional unit in the brain. yes, the neuron is a basic building block of information processing in the brain. But what is special about language, memory and so forth in the brain?

It is possible that Arshavsky is not radical enough: what we should seek out is to avoid using generalistic and folk-psychological concepts in the first place. We should possibly not study “language”, “memory” or “consciousness”, since these concepts will always allude to fundamental assumptions of “language-ness”, “memory-ness” and “consciousness-ness”, IOW that there is something more to explain after we have found out how the brain produces what we recognize and label a cognitive function.

Maybe neuroscientists are not using a poor strategy after all? Maybe ignoring the past history of philosophy of mind is the best solution. I’m not sure (nor am I sure that I represent Arshavsky’s view properly). But how we choose to label a cognitive function depend on our past historical influence and learning, as well as our current approach.

-Thomas

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pvs.jpgIt’s all in the news these days. A man who has been in a coma (or is it “coma-like”, “almost coma” or what?) since a car accident in 1984 has now regained consciousness, and cognitive abilibties such as his speech. It’s already been written so much about this topic, but little is actually addressing the science. Often, the sensationalism is only covered. You can get them all by this simple google.

So why start writing about this here at BrainEthics? The story should have been covered by now? I think there are several reasons to address this story in a bit more detail, one of them being that the science, ethics and philosophical consequences are not – or very superfluously – noted. Another good reason is that the article describing this case has come out, and it’s available for free (PDF). Before we get to it, let me briefly let you know what I’d like to mention here:

  • the diagnosis – coma, vegetative state and related mental states are still very hard to tell apart, even to specialists
  • the development – much has happened to our knowledge about these states, but this knowledge has neither reached the general public, science writers nor always professionals dealing with these patients
  • the future – in addition to developments in traditional diagnosis, neuroimaging is already having a significant impact on our understanding on the relations and distinctions between these different states
  • the ethics – should we reach a scientifically valid model about states of consciousness the next step is to determine who is conscious and who is not – but still we are likely to ask “are our judgements correct?

The Diagnosis

If you are involved in a car accident and lose consciousness, the time from when you lose consciousness until you wake up is characterized by different stages where the brain’s level of functioning changes; from improved primitive reflexes to cognitive and mental restoration. A soon as you reach a state where you become aware of your surroundings, even the feeblest sensation, you have reach a state that is called post-traumatic amnesia (PTA). The person is conscious and appears responsive and they may even be able to talk to family members and medical staff, however after a short time, the person will forget all recollection of conversations and actions. The person will be disorientated and may not know the date, where they are, or why they are there.

The important discussion here is that we are discussing whether a person is conscious, or if he has any chance of becoming conscious again. A person in a coma is not conscious – he cannot be awakened, fails to respond normally to pain or light, does not have sleep-wake cycles, and does not take voluntary action. Coma is separate from vegetative state, in which the patient still has no cognitive neurological function or awareness of the environment. However, he has noncognitive function and a preserved sleep-wake cycle. Even more perplexing, the patient may exhibit spontaneous movements and he may open his eyes in response to external stimuli, and even track moving objects (or people) with his eyes. So why is this person not conscious? We know this from the fact that 1) he does not respond to verbal commands; 2) he shows no voluntary movements, only reflexes; 2) reports from people in this stage that have awakened show that they have had no experience. This, of course, is coupled to a variety of theory-bound measures of preserved vs. non-operative reflexes, and more recently neuroimaging.

What makes the diagnosis of coma and vegetative state so hard is that there are cases where patients show almost exactly the same symptoms as these conditions, only that they are aware. Patients in a minimally conscious state are indeed conscious, they may drift in and out of awareness, but they show signs of voluntary movement and communication. Terry Wallis is thought to be in this state, not coma, nor vegetative state. Another condition is locked-in syndrome, in which the patient is aware and awake, but cannot move or communicate due to complete paralysis of all voluntary muscles in the body.

The frequency of misdiagnosis of these patients has not been reviewed in full, but the fear is that it happens more often that we would like to. The misdiagnosis goes both ways: sometimes a patient is thought to be conscious while actually being in a persistent vegetative state. Other times – and this is the most problematic error – a patient that has some level of awareness (e.g. locked-in) is diagnosed with a coma or vegetative state.

The Development

How can we be so wrong about these patients? One reason is that we have just began to explore this field at the level of detail that we do today, incorporating better diagnostic tools and multi-modal assessment tools such as EEG, SPECT and MRI. A willingness to study consciousness, that mongrel concept that we still really don’t know what means, is another reason for the recent developments in this field. In all, our ability to distinguish between conscious and unconscious states has gone from a dichotomic distinction to a range of possibilities that are sometimes hard to distinguish.

This development is often the reason to the sensational awakenings that we can hear from time to time. News about a person regaining consciousness after 20 years from a coma (!) should be taken with a grain of salt. 20 years ago the diagnosis and distinctions to other (conscious) conditions was notas developed as today. So we should maybe think of this rather as a sensational awakening of the science surrounding these patients, not the patients themselves. That’s a bit harsh, but it is true that the conceptual and diagnostic improvements in this fueld has come through the past few years only.

The Future

What can we expect to happen in this field? First of all we can expect that neuroimaging tools will be used more. Today we can record EEG to exclude ideas about brain death; we use MRI images to see where in the brain we find lesions. But studies showing differences in the brain’s activity between these different patients have been emerging – see this article (PDF). The problem with these studies are that they are group studies. As I have argued previously, going from group study mean differences to the ability to identify individual differences – and diagnosing people on this ground – is not a straightforward thing. So tools needs to be developed that makes it possible to look at an individual scan to determine whether a person is conscious or not. As Steven Laureys from the University of Liège says:

Chronically unconscious or minimally conscious patients represent unique problems for diagnosis, prognosis, treatment, and everyday management. They are vulnerable to being denied potentially life-saving therapy….. This case shows that old dogmas need to be oppugned.

It should be noted that efforts are already being made for developing a “consciousness meter“. This stems from the finding of mid-operational awakenings; people undergoing surgery that are put into anaesthesia nevertheless wake up during surgery yet without the ability to notify others about their presence, often suffering pain as their sensations are restored. In other words; an induced locked-in syndrome. However, interesting as it has been it’s been hard to find any updates on the effectiveness of this apparatus. But we should probably think along these lines. Saying that, the consciousness meter suggested is based on EEG, and any measurement of a traumatised brain is bound to show different signals. That needs to be kept in mind.

What, then, about treatment? This is bound to follow the trace of our enhanced knowledge of these conditions. But what is interestig with the case of Terry Wallis is that he showed signes of rewiring of fibres in the brain. While these findings are in no way conclusive, they suggest that new intervention tools can be developed that focus on the regeneration of fibres in the brain. Not only general restitution, but maybe more focal, to the regions in which we have seen Wallis’ brain change (see changes in cerebellum, as indicated by white arrow below).

17103-singer-070506-brainscan.jpg

Diffusion tensor images of a brain at the first scan (left) and 18 months later (right). Color shows direction of white matter fibers, e.g., green for anterior-posterior fiber tracts. Large red area in second scan (arrow) shows what scientists think is growth of new neural processes in a part of the brain that controls movement. (Credit: Weill Cornell Citigroup Biomedical Imaging Center/Henning U. Voss.)

The Ethics

The growing knowledge about brain function and diagnosis of these cases should make us ask whether we are using the most up to date knowledge about these stages and states. Even more troublesome, spreading the knowledge to the entire world is a problematic affair, and even within the developed world. One thing is having an operational diagnostic system; an entirely different thing is seeing it implemented throughout the world. While the diagnosis of brain death is more or less universal across regions, cultures and religions, spreading the news about differential mental state diagnosis is only now beginning to spread. Hopefully, the use of evidence based medicine will provide the tools for such a knowledge dispersal.

Understanding that there is a tight relationship between the brain and the mind has a deep impact on our self-knowledge. Knowing how the brain works and breaks is a tale about yourself. It’s a direct relationship, not only a superficial association of flesh and mind. A loss of brain function is a loss of mental life (or part of it). All in all, the scientific study of unconscious states such as coma and persistent vegetative states are one part of the story that ties the brain and mind together tightly to a coherent picture of our minds as natural, biological phenomena.

-Thomas

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dennett.gifDan Dennett is interviewed by Robert Wright about his views on evolution and consciousness. Their views on evolution differ, especially with Wright's contention that evolution is goal-oriented in someway, and that history progresses in a predictable direction and points toward a certain end: a world of increasing human cooperation where greed and hatred have outlived their usefulness. All in the name of evolution — and game theory, that is. IMHO it's a lot of gibberish. Evolution is not teleology. It's a gross misunderstanding of the principles of evolution. I think Dennett does a nice job at pointing this out. Wright is not all ears, though.

On the second topic, consciousness, Wright and Dennett disagree profoundly. I'm not entirely sure whether Wright takes on the job as a Devil's advocate, or if he really means that epiphenomenalism is a logical possibility. I think the latter: Wright seems totally agnostic towards Dennett's thoughts. They simply won't penetrate Wright's mind.

If you listen carefully (with earphones, like me) you'll hear Dennett make a dozen sighs along the talk. I can understand why. It's a Sisyphean task to discuss these topics, and you're bound to run into people with the same scientific agnosticism or even atheism that hinders true progress in our understanding of topics such as evolution and consciousness.

You can find the interview here.

-Thomas 

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