Imaging and the Question of Consciousness
Neural and Behavioral Sciences Senior Seminar
Bryn Mawr College, Spring 2010
Imaging and the Question of Consciousness
In 2007, the New York Times published some startling news: “based on analysis of brain-imaging data from just a handful of swing voters, they had divined what the rest of the undecided masses truly think about the upcoming US presidential elections.” John Edwards was subconsciously disgusting to supporters, because viewing his image activated the insula and the insula is associated with feelings of disgust. If accurate, this finding marked a radical departure from the uncertainty of the poll to dialogue on the hidden and multifaceted workings of individual minds. The use of fMRI and other functional imaging techniques is often claimed to reveal long-pursued facts about consciousness, from the local origins of love to the emotional content of a sandwich. Many feel, however, that enthusiasm for finally answering these questions has blinded journalists and researchers to the technical limitations of the technology, commenting extensively on its potential gaps and misdirections. Still others propose that our theoretical framework is not constructed in a way likely to uncover the causative link between brain and mind, arguing for an adjustment in the goals and methodology of functional brain research.
- Fact or Phrenology? Scientific American, 2005
- How to Solve the Mind-Body Problem Nicholas Humphrey, 2000
- Mind Games Nature, 2007
- Neural correlates of interspecies perspective taking in the post-mortem Atlantic Salmon: An argument for multiple comparisns correction Dartmouth College, 2009
Also of Interest:
- This is Your Brain on Politics. Any Questions? Bad Science, 2007
- MRI Lie Detection to Get First Day in Court Wired, 2009
- Re-Thinking Jeffery Goldberg The Atlantic, 2008
Discussion summary (Sarah)
As an introduction to our discussion of imaging, Jeremy and Bobby presented a screen-shot of a research poster entitled “Neural correlates of interspecies perspective taking in the post-mortem Atlantic Salmon: An argument for multiple comparisons correction.” This study claimed that they saw BOLD fMRI activity in a dead salmon after presenting the salmon with a photo. Although this gave us a good laugh, more importantly, it was the jumping off point for a discussion regarding why fMRI data is not completely empirical and the limitations of fMRI. Some of the limitations discussed by the class included:
- BOLD technology assumes mapping neurons using the most oxygen is a true map of brain activity (this ignores signal origination and the circuitry of the nervous system)
- BOLD cannot distinguish between excitatory and inhibitory events
- One only sees activation if there are a large number of neurons using oxygen in the same location, not if one neuron each is using oxygen in disparate parts of the brain. (These are only a few of the many limitations discussed.)
Next, we began to transition to a debate as to whether fMRI is better than phrenology, and whether we can be more or less sure of fMRI data than lesioning or physiology data. Issues brought up by the class included whether fMRI can pinpoint the location for love in the brain (general consensus was that fMRI cannot do so) and the political “mind-reading” of swing voters. The political analysis study claimed that if subjects showed high activation in the insula when shown a photo of a particular candidate, they were disgusted by that particular candidate. Although this study was published in the NYT, it was performed by a commercial outfit that was hoping to sell this “imaging product” to companies as a means to figure out customers’ “true” desires and views. Again, this study was quickly debunked by the class based on the knowledge that fMRI activity does not allow an empirical activity → function interference. Paul, however, then brought up the issue as to whether fMRI/MRI allows for greater confidence than do physiology or lesioning. As a class, we initially claimed that lesioning is more useful, citing patient H.M. as an example. Although patient H.M. allowed the neuroscientific community to learn a lot about memory, Paul encouraged us to be cautious, and brought up the issue of lesioning the visual cortex. When the visual cortex is lesioned, patients report not being able to see; however, when they are asked to point to where an object is located while pretending they can see, the patients are generally correct. This example compels us to question all of our methods of inquiry, noting both limitations and strengths inherent.
We also delved into the assigned reading, “How to solve the mind-body problem,” by Nicholas Humphrey. The class wondered whether sensation is equivalent to consciousness, or does sensation only exist in the present moment? After some clarification assistance from David and Paul, we concluded that sensation is roughly equivalent to primary consciousness. Humphrey in fact asserted that sensation/primary consciousness necessitates nervous system involvement, and is not simply an input only phenomenon. This allowed us to conclude that sensation is an active process, but that there might not be a demonstrable place in the brain where these sensation/consciousness processes occur.
Lastly, Jeremy asked us whether if we possessed the technology in which imaging could tell us everything about the brain, is this something we would want? Or is this an invasion of privacy? Megan expressed doubt that we would ever reach this point in imaging technology. Others equated this type of imaging to a lie detector (a remarkably more sophisticated/complex, and hopefully, more reliable one at that). Some students believed that this level of technology would be an invasion of privacy, but then others aptly pointed out that we would not sneak up on someone with a huge fMRI machine – they would have to be warned. We continued debating whether or not this technology will actually come to fruition in the future – a study was mentioned where fMRI/MRI was able to draw the shape a person was thinking; however, this was only after the individual’s pattern of thinking regarding particular shapes was learned by the machine/computer. Consequently, these types of technologies would have to be individualized for every person in order to be used to determine if someone was lying, etc. Before the class ended, we briefly talked about the privacy issues, job screening, and laws that would accompany this type of technology- hopefully we will continue this aspect of our discussion next week.
Continuing conversation in forum area below