Tuesday 8 June 2010

Confusion about EEGs and fMRIs in my JCS paper

So, I had a paper published last month in the Journal of Consciousness Studies (JCS). I'm very happy about this, especially as it resulted in brief discussions on the journal's yahoo group's messageboard.

I'm particularly happy about this as this journal is what brought me back to philosophy. In 2002, I was working as a waitress in a hotel bar - hold on, no I wasn't. I was working as a technical support engineer/software consultant - the title kept changing - in a desolate industrial estate just a few miles from Schiphol airport in Holland. On my breaks, I found a series of articles and discussions about consciousnesss. The one that struck me was 'Facing Up to the Problem of Consciousness' by David Chalmers in JCS (free-to-read here). I'd gotten quite cynical about philosophy after my undergraduate - definitely partly due to not having done any work for my BA. After reading Chalmers' article, I got interested again. Never thought I'd be published in the JCS myself, though. Alot of things have changed.

Like my professional situation. In February, I applied to IRCHSS - the Irish Research Council for the Humanities and Social Sciences - for my two-year project 'Time and Illusion' at University College, Cork. Two weeks ago, I found out that I got it. Again, I am very happy. In Dublin at the moment for a meeting of 'awardees' tomorrow in Dublin Castle.

Anyway, enough about me - more about my mistakes. In my JCS paper, I discussed a possible experiment for finding out if there is a privileged frame for the neural correlates of experience - or, at least, the subject of the experience. This experiment turns on measuring the velocity of the neural correlates. The evidence needed is a common velocity, i.e., not a velocity relative to each subject, for the neural correlates in all subjects. In setting up the experiment, I suggested you could do this with an fMRI or something like that.

However, as I discovered in discussion with my friend David Jenkins, this can't be done by fMRI. fMRI - or functional Magnetic Resonance Imaging - is a method of mapping activity in the brain. To quote from the Columbia site, it does so by tracking increases in blood flow. It doesn't measure the movement of the correlates themselves. Positronic emission tomography, or PET also only measures the blood flow. EEG (electroencephalography) does seem to measure neural activity directly but it does not seem to do so finely enough to pick out the motion that's needed.

This, however, is not a problem for the argument of my paper. It is a problem for those who object to it. So it is not a serious issue for the position I promote. But it still shows that I should pay more attention to the actual detail of how things are made, and what they can do. I forget that most things I encounter have limits. They can break; they are finite. Even the  internet you're reading this on is not some spiritual non-physical dimension of thought. It's electric fields, dark dots in hard disks, copper wires and undersea cables. It is a multitude of such things, the locations of which are not easy to find. But the multitudes are finite, and they are somewhere. You can break the internet by pulling enough plugs.

Anyway, enough!