Imaging and the Question of Consciousness

          I agree that fMRI has a long way to go before its findings can be
completely understood. We just have to wait for the technology to catch up
with us. However, the world isn’t exactly waiting patiently. As we’ve seen
they are already trying to link its findings to certain emotions,
consciousness, and using it as a lie detector. Two companies have even
gone commercial using BOLD fMRIs to be used as lie-detectors. What is most
interesting to me about fMRI is not what it is necessarily good or bad at
doing, but how its ambiguity is taking the media and even taken the legal
system by storm. The uses of fMRI have become darling to the media.
Currently, a number of legal cases are trying to use fMRI readings to hold
up in court. For instance, there is an ongoing sexual abuse case in which
the defendant is trying to prove their innocence by an fMRI lie detector
provided by a commercial company, No Lie MRI. This company claims that
they can prove the defendant’s innocence. Controlled scientific studies
claim that fMRI lie detectors have between 76-90% accuracy. However, these
studies did not take place in real world settings with different
pressures. Nevertheless, it will be very interesting to see how this case
holds up in court. Even if fMRIs become the next big thing in lie
detection, they are nowhere near foolproof as scientists say they are
still easy to trick. You just think of random things, moving a little, or
holding your breath and the results are rendered worthless. But I guess
the jury’s still out on whether or not the strengths and weaknesses of
fMRI lie detection still beat the status quo. Personally, I’m holding onto
my vote a little longer.

  I am intrigued by the concept that memories may exist as small changes distributed throughout the nervous system.  If this is true, then the possibility of using fMRI as a lie detector seems unlikely.  While it may be possible to use fMRI to predict what a person is currently looking at (as with the study we mentioned in class), this is a much more basic task than identifying memories.  We may have defined (individualized) “maps” of activation when looking at a picture of a house, for example.  However, recalling a memory may induce very different brain activity than the activity created while receiving real-time visual input of an image.  Because imaging techniques look for areas of strong localized activity, it seems unlikely that fMRI would ever be able to detect a subtle and diffuse signal characteristic of recalling a particular memory.  Because the practical use of lie detectors is to question someone’s memory (not whether they are currently looking at a picture of a house), it seems improbable that fMRI would be very useful in this context.

Lots of food for thought, both in last week's session and in the follow up discussions here.  Some things that stick in my mind for continued consideration ...

I share a sense that imaging studies, like all studies, have both uses and limitations, and like the idea that what we can have most confidence in is what is supported by observations using multiple techniques (cf EB, Sarah).  At the same time, the discussion highlighted some deeper problems inherent not only in imaging but also most other studies with which imaging studies might be compared.

One aspect of these problems has to do with a localization presumption, and an associated inclination to average and to attribute special significance to locations that display relatively high average activity.  There is no assurance whatsoever that the brain is actually organized in ways that fit these presumptions.  It is entirely possible, indeed even likely, that diffuse activity, of a kind that will not be detected as localized high average activity, plays a significant role in many nervous system processes.  That we can detect areas of high average activity correlated with particular behaviors provides no evidence whatsoever that those are the critical substrates for generating those behaviors. 

The history of the search for "memory traces" provides an apt case in point.  Reviewing his extensive program of lesion studies, Karl Lashley wrote in 1950 in his classic "In Search of the Engram"

"It is not possible to demonstrate the isolated localization of a memory trace anywhere within the nervous system"

The situation has not changed since, despite extensive and ongoing research using a variety of techniques.  Indeed, the upshot of subsequent research has been to establish fairly convincingly that in general "memories" involve  distributed small changes that are widely distributed throughout the nervous system and that they are, to a large extent, constructed and reconstructed in real time.  In short, there is no "engram" of the sort that might be detected as localized high average activity.  Areas exhibiting high average activity in imaging studies, like those that "abolish" memory in lesioning studies or those that yield memories when stimulated electrophysiologically , are more likely to be involved in constructing memories than to be the storage depot for them. 

The point here is not that "localization" doesn't exist in the nervous system.  It certainly does, but what is "localized" rarely bears any strong relation to the functions we are inclined to believe exist from observations of behavior.   There is lots to learn from imaging studies (Allison), as from lesion and electrophysiological and pharmacological ones.  What needs to be kept in mind in all cases is the importance of doubting findings that fit neatly with what we presume we ought to be looking for, and so have developed the techniques to find. 

The other deeper and more general problem that our discussion of imaging technologies seemed to me to highlight is the presumption that particular patterns of brain activity should generalize across people, and across particular times and contexts for individual people.  Why should we think that either "lying" or "redness" corresponds to the same pattern of activity in different people, or even to the same pattern of activity in the same person at different times?  They might, of course, and its certainly worth asking the question given available techniques, imaging included (cf David F).  But its the sort of question that should be asked skeptically, with full awareness of the limitations of techniques and the bias to find what one is looking for.  What one should be looking for is not the expected but the unexpected. 

Along these lines, my own sense of the degree to which the brain is continually constructing and reconstructing makes it entirely possible that "lying," "redness," and most other things of this sort are actually a lot like the river Mark Twain describes in Life on the Mississippi.  What makes the Mississippi the Mississippi is not that it has the same pattern at any given time; it is constantly changing with the time of day, with the seasons, and with the years.  The notion of the Mississippi is a construction of the brain, an effort of the brain to create some constancy to make sense of ongoing change.  Given that, my own guess is that the Mississippi as well as lying and redness are related but not quite the same thing in different brains and related but not quite the same thing in a given brain at different times (Vadilson, Vidya)

We can certainly try to "calibrate the fMRI to any individual" and look for "generalization across people" and learn something about the brain from efforts to do so.  Perhaps though what we'll learn though is that there always remains an uncalibrateable and non-generalizable individual distinctiveness, and that this is part of the essence of brain function?  If "fMRI results differed from the subject's verbal accounts" (David F) then the fMRI results are incomplete, reflecting activity in some part of the brain other than those involved in verbal accounts, and an associated internal disagreement   

If so, we can stop worrying about threats of  "mind reading."  The problem isn't that others can see what we are in all its complexity but instead that people might assert that we are things different from and simpler than what we actually are.  That's a problem that long predates imaging.  Maybe its a problem that good brain research, including imaging, might actually help to solve?  

I agree with Sara in that most imaging studies are probably somewhere in the middle between the extremes of absolute scientific accuracy and complete fiction. And yet, I felt like last week’s class was mainly spent as a bashing session on fMRIs.  I honestly wonder about the usefulness of that mind frame. As stated, already, in the forum, neuroscience tools have helped us gain a much greater understanding of the brain. No technique is perfect. And as scientists/researchers, I think we would almost all agree that the best data is data that can be supported by different techniques. Do we get the same type of result when we use an antagonist as we do when we ablate?  If yes, then we feel more confident that our findings hold true scientific value. Scientific advancement takes time. Is it really useful to spend the majority of our time critiquing a technique because its accuracy isn’t yet up to our… standards?  Our expectations?  Who are WE? I agree that it would be a mistake if the scientific community became obsessed with fMRIs to the point where they believed the technique to be completely fool-proof, but who is actually doing that? Who, from the scientific community, is actually coming out and saying that fMRIs are perfect?  I don’t think anyone is. Brain imaging techniques have taught us about brain activity. Imaging studies can be used, not as the only way, but as another way to understand the puzzle.

In class we spent a lot of time discussing the downsides of fMRI and imaging technologies.  However, I think it is important to remember that these are important tools that have helped us to gain a much greater understanding of the brain.  As long as we fully understand our results as what they are and not as a distinct map of all brain activity related to a given stimulus, or as a way for us to "read minds," fMRI is an extremely useful tool.  Despite the fact that MRI shows voxels that are much larger than a single cell, it still provides good spatial resolution for activity in the brain.  EEG, which has an almost immediate temporal resolution, lacks in spatial resolution, but it still has provided insights into the different roles of different brain areas.  Despite the generality of all of these imaging methods, they have still taught us about brain activity.  While it is important to remember not to veer towards "neo-phrenology," it is also important not to discount the findings of imaging technology studies.

As far as using fMRI as a lie detector, I don't feel that it is less ethical than the use of a regular polygraph.  While that may not be ethical itself (it's often wrong), if we could get an MRI to work as a good lie detector I could support its use in courts.  Since that seems to be one of the only uses of lie detectors in general (ie, there aren't lots of home lie detector systems on the market - or are there?), I think it's within the bounds of what is ethical.  Of course, I wouldn't support the use of MRI as a lie detector by a totalitarian government or anything of the sort, but I don't think the technology is headed in that direction.  While there are plenty of articles that claim that MRI is being used for "mind reading," I believe that these articles are really trying to make the story more sensational.  What these scientists seem to be doing is finding different patterns of brain activity that occur in different situations, and studying them to see how the brain processes different kinds of information, not reading minds.

      One aspect of the issues with fMRI I think that Vadilson was alluding to is how easy it is to overgeneralize maps of the brain.  I have been thinking about how the nature of cancer therapy is going to radically change to be completely personalized as scientists learn more about the vast differences among cancers and the genes mutated in specific cases.  Similarly, I think that once we realize that we can't juxtapose two different people's brains to determine if they feel similarly or differently about an image, the use of fMRI may be used for "pop" psychology.  All of the exciting uses we have been thinking of for fMRI- like lie detectors, focused advertising, determining personal feelings about political candidates- may not be as cost-effective or simply effective as we believed, leading major scientists to look elsewhere.  Hopefully, as the flaws in fMRI become more well-known, colorful pictures of brains won't be sufficient to seduce editors of major newspapers and magazines into publishing semi-scientific results although, honestly I think it may be that they are the only ones who will publish that data. It's unfortunate that as scientific technology has progressed and become increasingly specialized, there's a separation between the data and results that are presented to the public and those that are published in scientific journals.  Perhaps fMRI will become relegated to newspapers and magazines but not accepted as convincing enough data for Nature or Science publication.