The runaway trolley and brain damage

For a video-podcast of me outlining the basics of the trolley problem see: http://philosvids.wordpress.com/2013/03/16/the-trolley-car-dilemma/ 

Some of you will have discussed in class the classic moral problem sometimes known as the runaway trolley case - where a trolley car is running out of control down a hill - and is about to kill 5 people, but you happen to be stood by a switch - with a lever: pull the lever and it switches trackes and the 5 people are safe.... but (there's always a 'but' in these examples) there is one person on the other track - do you pull the lever 'killing' 1 and 'saving' 5?

Now - you will recognise in this issues of Utilitarianism, and there are numerous variants that demonstrate some of the problems associated with assessing situations on the basis of utility... what if you knew some of the people - or if the 1 was a doctor, and the 5 were criminals on work-release - etc... Other variants include an example where there is no switch but you can push a man (in some version a fat man) in front [you are unable to put yourself in its path] and hereby save the 5 - is this different?

In surveys people are often reluctant to act when it involves an act which seems so directly like 'killing' - but I came across this interesting article in the New York Times which quotes a survey that seems to link answers to this variant version to areas of the brain - via a survey involving people with damage to certain parts of their brain. It is at: http://www.nytimes.com/2007/03/21/health/21cnd-brain.html?_r=2&hp&oref=slogin&oref=slogin

If we accept this - what does the link between brain areas and moral choice say about the nature of moral choice itself?
Dave