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Archive for the ‘neuroimaging’ Category

OK, here we go again. Remember the fuzz about the Iacoboni lab at UCLA, where they used fMRI to probe into voters likes and dislikes of politicians? Now,a good article in the Atlantic.com gives us a 1st person story about the trip through the fMRI experiment, the thoughts and results following this scientific un-rigourous and invalid approach. Jeffrey Goldberg reports in a funny and entertaining manner how it all goes about.

As with the previously mentioned NY Times article by the Iacoboni team, Goldberg is scanned while watching different famous people, including politicians, actors and musicians. After a few days, the imaging results come in and are presented and discussed with Iacoboni. To me, the dialoguoes could be referring to tea-leaf reading, astrology or ___ (put in your preferred method). As here:

(…) what happened when I saw a picture of my wife. This had me concerned, but Iacoboni explained: “The dorso-lateral prefrontal-cortex activity means you’re trying to exercise cognitive control, that you’re trying to protect the privacy of your relationship with your wife. I interpret this positively because there’s also medial orbito-frontal cortex activity, which is a region associated with positive emotion.” Iacoboni could not explain one other response to my wife’s photograph: “You have weird auditory-cortex activity, almost like you’re hearing her voice, even though we just showed you her picture without sound.”

OK, so give me some (peak) activation in the brain, and I’ll try to interpret it. I’m the Rorschach inkblot master, just bring it on! Actually, thes best thing with this article is the humorous angle that Goldberg puts to it. Just following the above citation, he notes:

When I told my wife about this, she asked me how it could be that I hear her when she’s not speaking, but don’t hear her when she is speaking. I said that this was a question well beyond the capacity of neuroscience to answer.

To newcomers and outsiders, it is crucial to understand that there is a substantial difference between studying brain activation related to specific behaviours and/or tasks, and to go the other way and interpret mental states or behaviour from brain activation patterns. The brain is much more than a collection of highly specialized regions, and there is considerable redundancy and degeneracy in the brain. This means that one structure can be involved in many different functions, and one function or state is often served by many different regions at any one time. So whether your brain responds with the amygdala to a particular face, compared to other faces, may not even mean that you fear or are concerned with this person. The amygdala may be involved in positive emotions, or even novelty processing. Brain-reading is a fascinating topic, but we should steer away from the absolute claims that one can sometimes see today.

One good example, in the present article, of what this approach may lead to is the finding that the author showed ventral striatal activation to the Iranian political leader, Mahmoud Ahmadinejad. So ventral striatrum is related to (expectation of) reward, right. And previously, activation in that region to other famous people was interpreted as a liking-effect, right. Now what? Does Goldberg like Ahmadinejad? Will the NSA knock on Goldberg’s door in the near future? Is it illegal or suspicious for his brain to respond favourably to Ahmadinejad?

This, and more puzzles are definitely going to come up in the near future, as Iacobini and other researchers are concinuing this flaky path of BS science. I’m a great fan of Iacoboni’s academic work, but I am nevertheless terribly dissapointed with his uncritical turn towards entertainment with fMRI.

-Thomas

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sciencefraud.jpgMartha Farah just alerted me about her recent comment in the Neuroethics & Law blog. Yesterday, NY Times ran a story about neuro-politics. More precisely, they presented a study of how subjects’ brains responded to, e.g., different political words and pictures of US politicians involved in the 2008 presidental election. The article’s first author is Marco Iacoboni from UCLA. Basically, the researchers give subjects different kinds of tasks, report activations in different regions of the brain (that themselves are likely enough to be involved during the tasks). Then, the authors set out to interpret this activity, such as:

When we showed subjects the words “Democrat,” “Republican” and “independent,” they exhibited high levels of activity in the part of the brain called the amygdala, indicating anxiety

Didn’t I just say that the amygdala is involved in positive emotions, too? So what does amygdala activation mean, then? Studies have also shown that mere emotional uncertainty (e.g., a neutral face) may activate the amygdala. So maybe the political words are just more emotionally ambiguous? Let’s take another one from a different part of the article:

With Mr. Giuliani, the reactions are reversed. Men respond strongly to his initial still photos, but this fades after they see his video. Women grow more engaged after watching his video.

OK, where did men respond more strongly? The whole brain? WOW! Let’s continue to a third place in the article:

Our subjects also exhibited a much stronger empathetic response to a minute-long excerpt from a stump speech by Mr. Thompson than they did to an excerpt of a Giuliani speech.

So what was compared? Two speakers, two political opponents, two speeches, or ___ (add your favourite). OK that’s just three examples, but the article is full of such tea-leaf reading. It’s nothing short of magical thinking, astrology or healing. Put differently, the authors look at brain blobs and try to interpret their meanings in terms of previous knowledge. Is that bad? Yes it is, because it does not even attempt toput up testable hypotheses. And why don’t we get to know what is meant by “more active” or “respond more strongly”? What is this activation compared to? What is the contrast, the baseline? Even further, what is the statistical cutoff and how many other regions light up during conditions X, Y or Z? Where are all the tech specs that validate this study?

So is this really our brain on politics? Or is it the Iacobini team’s own ambition to get publicity (and maybe earn some money along the way)? I’d say the latter is the case here. The basic problem is that we don’t have a scientific reference, and only have to take the authors’ word for it. It’s a violation of every sensible way to report findings from a scientific method in the press. IMO, before you can do such a thing, you should at least (!) have a manuscript that is accepted, let alone published. And if you choose to do a test for the media, just “for fun”, then say so! This article pretends to be scientifically correct. It is not.

How this has come through the press is probably the most interesting story. And how it got through the science editors at NY Times is a mystery. Indeed, I hope that more criticism will force NY Times to send out a corrigendum.

-Thomas

NOTE: As I hoped for, this story has spurred a lot of discussion, e.g., here.

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textbook.gifWhile we’re still at books news from the Brainethics duo, here is another new thingy:

The excellent new textbook entitled “Cognition, Brain and Consciousness”, edited by Bernard Baars and Nicole Gage, is finally out from Academic Press. It’s a highly readable book, rich in illustrations and examples. Judging from the reviews it has received so far, it’s going to be a popular book.

I participated in writing the two chapters on brain imaging methods, one on the “surface intro level”, and another more in-depth description of methods (an appendix). In a similar vein, other authors have contributed to both an easy introduction as well as more in-depth discussions, making the book accessible to both a broad audience as well as an update to those already in the field of cognitive neuroscience (I learnt a lot by reading other author’s chapters).

-Thomas

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broca.jpgNature is running a nice news article on the re-localization of Broca’s language area in the brain, and has as feature about it in their latest podcast.

Pierre Paul Broca originally described patient cases in which the patient suffered speech production deficits following injury to the left frontal hemisphere. However, a revisit to Broca’s original papers (see translations here and here), combined with a modern scanning of the preserved remains of Broca’s patients, has revealed that what has been called Broca’s area in modern times does not correspond to the areas implicated by Broca in his patient descriptions and neuroanatomical descriptions.

The story is interesting, but I’m amazed that the excitement is running so high. After all, lots of papers have already dethroned Broca’s (and Wernicke’s) area in the role of language processing. Take the example of the special issue of Cognition on language. Basically, what we know about language in the brain is beyond the talk (!) about Broca and Wernicke, and especially the models they suggested. Rather, both language comprehension and production require a larger neural symphony, and with substantial internal redundancy. IOW, Broca’s area can participate in comprehension, and Wernicke can play a part in production.

Nevertheless, the Nature news article is a good read, and I always recommend the Nature podcast.

-Thomas

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brain-reading.jpgBack in February, BBC ran a story about fMRI researchers – shock, horror! – now being able to read people’s minds. In actual fact, the story was a bit more benign. Using a fairly new (and little used) type of fMRI analysis called “multivariate analysis” researchers such as Geraint Rees and John-Dylan Haynes are presently attempting to associate individual mental states with specific patterns of BOLD signal activity. If the mental states of interest can be precisely delineated it is possible to determine if a subject is “in” mental state A or B just from looking at the scanned fMRI data. For instance, in one experiment, described in the BBC story, subjects were asked to either subtract or add numbers shown on a screen without telling the experimenters which of the two potential choices they actually went with. Just by looking at the obtained scans Haynes and his colleagues were able to infer, in 70 % of the cases, whether the subject chose to add or substract – thus, to some degree, being able to “read” the subjects’ hidden intentions. Of course, in reality, the experimenters’ mind reading ability was extremely limited, being focused on only two, highly simple, forced choices. (If you want to read a good presentation of the mind reading possibilities offered by multivariate analysis, see this paper by Rees and Haynes.)

Yet, with all the recent talk about fMRI lie detection and what have you, work such as Haynes and Rees’ on multivariate analysis raises a number of interesting neuroethical questions. On May 9, Haynes is convening a bunch of top-notch speakers to discuss these questions, including Daniel Langleben (of fMRI lie detection fame), Adrian Owen, Henrik Walther, and Thomas Metzinger. He presents the colloquium with the following words:

Every thought is associated with a characteristic pattern of activation in the brain. By training a computer to recognize these patterns, it becomes possible to read a person’s thoughts from patterns of their cerebral activity. In this way a person’s brain activity can betray their thoughts and emotions, can gives clues whether they are lying, or can even predict what they are about to do.

This recent progress in brain science has made completely new insights into thought processes possible. We can now investigate how thoughts are stored in the brain, or how intentions unconsciously arise and affect our behavior. But these findings are not just of interest for the scientific disciplines involved. They have important implications for our understanding of human nature. Also, they lay foundations for important applications: For example, with the help of a “brain computer interfaces”, paralysed patients can control technical devices solely “with the power of their thoughts”.

In the 11th Berlin Colloquium, brain scientists from the USA, Canada and Europe will present this new field of “brain-reading”, while at the same time providing a forum for discussion on the future perspectives of these methods. In particular, the ethical question will be of interest, to which extent such “thought technology” is compatible with “mental privacy”.

It should be well worth your time going.

-Martin

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Is it possible to identify a psychiatric disorder using a structural brain scan? According to a team of researchers from Europe and Australia this can indeed be the case. In a recently published study in NeuroImage, researchers Carles Soriano-Mas et al. demonstrate that structural brain scans can identify subjects suffering from obsessive-compulsive disorder (OCD) with a 93.1% classification accuracy (for a whole-brain comparison). In addition, individual variance in OCD symptom severity was correlated with the measured neural differences. In other words, the more you suffer from OCD the more you are likely to stick out in the analysis as an oddball, compared to a healthy norm.

Here is an image showing the structural differences between OCD patiens (n=72) and healthy controls (n=72):

brain1.png

In the image, the heat scale indicates regions where OCD patients differ significantly from controls at the whole brain level. Interestingly, when the researchers focused on the most intense regions the predictive value of the brain scans dropped to 76.6% accuracy. This means that a whole-brain approach is the optimal for determining whether a subject is suffering from OCD.

The study clearly demonstrates that neuroscience is moving in the direction of single-subject analysis, and the application of advanced analysis methods to determine whether a given individual is structurally (or functionally) within the normal range. If the means are there, when will we see them being used — and misused? After all, if a brain scan has the close to 100% accuracy of telling whether a person is suffering from OCD, why not use it in the clinic right away? Or better, why not expect applicants to an important company position take such a scan? After all, if you suffer from OCD, you are less likely to be able to be in such a position, right? And while we’re at it, why not try for a similar approach for depression, anxiety, stress and introversion?

Are we right in being sceptical towards the application of such measures of psychic health? Methodological problems aside, should such a measure provide a robust assessment tool, why should we not use it? After all, psychological testing is really aimed at uncovering who people are. Apply for a top position and you are likely to be submitted to psychological and cognitive profiling. If scanners provide a better accuracy, would it not be preferable to use this method? Since society has decided to allow psychological and IQ testing, such measures should really be just another improved method. As a consequence, we should not be surprised to see them being used pretty soon — if they are not already in the stores.

The solutions are far from clear in the muddy waters following the blazing trail of neuroscience. As neuroscientific methods move along and create new opportunities, new problems arise, too. What is important is to bring these issues up front in the media and other forums of such debate. Neuroethics is as important as ever.

- Thomas

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Is it really so that fMRI can enhance lie detection? This entirely depends upon your method of analysis, the experimental setup, and especially controlling for factors that influence the scanning results. Let’s take them one at a time

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