Snooping on your brain

[Steve.J]

Neuroscientists and clinicians have long been able to monitor the signals on the surface of you scalp and within your brain.  Known as EEG or electroencephalography, this technique is used for determining mental state (alertness vs. relaxation), evaluating sleep quality, helping to localize the focus and progression of epileptic seizures, and to make the legal determination of brain death.  This recording technique is most typically used to record spontaneous EEG - the gross and uncorrelated signals that are the result of billions of neurons firing spontaneously.  A special form of EEG is sometimes used to record the brainwaves that are generated in response to a repetitive stimulus.  In these recordings, signal averaging techniques are employed to isolate the response of regions of your brain to a deliberate input - possibly a flash of light.  In this way, it is possible to help localize the centers that are responsible for processing vision and determine the time progression of the various elements involved in processing and/or interpreting these inputs. 

Functional magnetic resonance imaging (fMRI) has brought these techniques to a whole new level. Researchers are now able to determine with a much higher level of spatial resolution which regions are activated during various stimuli. With this technique, it is now possible to actually "see" with some degree of accuracy what a subject "sees" by decoding the activity generated in primary processing areas of the brain. 

Check out this YouTube overview of the technique and the work done at the Gallant lab at UC Berkeley:

http://www.youtube.com/watch?v=6FsH7RK1S2E