MRI Machine

I said in the ‘About’ page that I’d post when I publish something relevant. Well, I am pleased to say that an essay by me has come out in a special issue of Paragraph called Reading Literature Cognitively, edited by Terence Cave. My essay is ‘Shakespeare, Perception and Theory of Mind’, Paragraph, 37 (2014), 79-95. Here is the abstract:

This essay explores the second ghost scene in Hamlet as an experiment in social cognition. It turns to scientific experiments on the relationship between vision and theory of mind, and to Shakespearean moments where audiences’ experience of the visual world of a play is shaped by what characters say they are seeing. The ‘Dover Cliff’ scene in King Lear is considered as an example of an audience’s constructive demeanour, rather than of the deception at the heart of theatre. The essay also recognizes the importance of the complexity of ghost belief in the period as a context for the scene’s apparent attempts to switch between the perspectives of Hamlet (who can see the ghost) and Gertrude (who cannot).

I’m not sure I’ve sold it very well there. I hope to come back to this theme (what literature, especially drama, knows about how we perceive things together) in the future, as I think I was getting somewhere…

I’ve also written a post for the Literature Technology Media blog run by some colleagues. They have been featuring a different ‘technological object’ each month, and I recommend every single one of the previous posts. This month I have written something about the MRI Machine. I focus on a few appearances of MRI in literature and film, and I touch briefly on prisons and music. What I didn’t write about much was my outing to the MRC Cognition and Brain Sciences Unit in Cambridge, where I visited a Siemens 3T Trio machine. Rik Henson kindly showed me round. An undergraduate friend and now an estimable neuroimager (neuroimagist?), he has already played a cameo role in a side-note in an earlier post here.
      One of the technical nuances I picked up didn’t make it into the piece for the other blog. It was that fMRI is good at saying where things are happening in your brain (within a few millimetres), but not so good at telling you when (and a few seconds is a long time in neural activation). In order to triangulate spatial precision with temporal precision, findings are tested using MEG (Magnetoencephalography), which is very good at time but not so good at space. The machines are very different: in an MRI it looks like you are being swallowed or entombed by the magnet, whereas in an MEG you appear to be wearing, and yet also sitting in, a very odd, very outsized, hat.

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Where MRI works with an enormous magnetic field, to which different substances in the body respond in different ways, MEG is sensitive to the absolutely tiny magnetic fields that result from electrical activity in the brain. The machine is housed in a metal chamber; everything possible is done to remove magnetic influences. I found this wonderful and strange: two machines with complementary attributes, aimed at the same mission, exploiting the same natural force, and yet they are fundamentally incompatible with one another. I suppose it could be difficult to recreate the same thought or feeling in both locations, if you want to establish the when and the where of a particular neural event. My impression is, though, as it is across the spectrum of cognitive science, that designing experiments to deal with such obstacles is where a lot of the excitement of the subject lies.

E-mail me at rtrl100[at]cam.ac.uk

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