Even though major science research has shown that there is no link between syndromes such as autism and multiple vaccinations, a major aspect proponents of the theory claim is the ingredient “Mercury”, that may cause many of the problems for brain cells and other behavioral functions. For example according to a study, Mercury that is present in MMR “readily crosses the blood-brain barrier, preferentially targets nerve cells and nerve fiber and degrades them”. [1]  [1] David Thower, A review of evidence between Vaccination and regressive autism, NTL World  , accessed 06/13/2011