MEG machine, University of Utah
What's in store for the future of brain scanning? Well, almost certainly the technology will grow only more sophisticated and precise, and less expensive and invasive. One new technology that is showing promise is:
MEG is a new technology that measures the very faint magnetic fields that emanate from the head as a result of brain activity. In MEG, magnetic detection coils bathed in liquid helium are poised over the subject's head. The brain's magnetic field induces a current in the coils, which in turn induces a magnetic field in a special, incredibly sensitive instrument called a superconducting quantum interference device, or SQUID. (The liquid helium bathing the coils is what chills them to superconducting temperatures, of -269 degrees Celsius.)
A single MEG device costs many millions of dollars and weighs about eight tons, so there are only a few worldwide.
Of all the brain scanning methods, MEG provides the most accurate resolution of the timing of nerve cell activity -- down to the millisecond. Hopefully, as the technology improves, MEG devices will become cheaper, more portable, and more prevalent.