I am meeting a professor this week to see if I can work in his lab. His area of research is magnetism. In a preliminary meeting, he told me that the 'ambient' magnetic field in the lab is about twice the magnetic field of the earth. I spent about 10 minutes in the lab. There was a machine with a high-speed faulty bearing that made a really loud screeching sound. I'm not sure if it was the ambient magnetic field or the loud noise that gave me a slight headache, increased muscle tension and strained my neck a bit. Does working for prolonged periods of time in such magnetic fields pose a general risk and in particular, affect neuronal activity, keeping in mind neuronal plasticity.