Your brain likes what it likes

Okay, through the wonder of Hulu.com, I found a clip from the NOVA program about music and the brain that I wanted to see.  It was only a 5 minute excerpt, but what I learned is interesting.  Basically, your brain can tell apart two different composers even when you can't.

Neurologist, and personal hero of mine, Oliver Sacks goes to a lab to have his brain scanned while listening to some music.  He prefers Bach over Beethoven, and, once he's strapped into an MRI machine (I think it's an fMRI, or a functional MRI, which means that it measures blood flow instead of just structural pictures), he is given a handheld gadget to gauge his emotional response to the music examples he's given to listen to.  When he is told that he is listening to Bach (or he can recognize Bach's music) he signals a strong positive emotional response and the MRI scan shows lots of reaction and response all over his brain.  Many parts of his brain are engaged (neurologists know this because the the MRI scans for blood flow.  Increased blood flow to a part of the brain means that there is increased activity in that part of the brain, i.e. the neurons are engaged and you're thinking or processing something.)  When he hears the Beethoven example, he signals a flat response, or negative emotional reaction and his brain scans shows very little reaction.  Only the frontal lobes lit up.

What was more interesting was when Dr. Sacks was confused as to which composer he was listening to.  He couldn't readily identify the example as Bach or Beethoven, but when they reviewed his brain imaging, the scientists found that his brain could tell when it was "hearing" Bach or Beethoven.  More parts of the brain lit up when Bach was heard.  It is interesting to think about how the neurons in your head can identify something that you consciously can not.  Is it the harmonic or rhythmic patterns or the way Bach concludes a phrase?  Is it note choice or is the argument invalid because Bach and Beethoven are from two different musical eras, Bach is Baroque and Beethoven is Classical-Romantic.  Fascinating.