C. Electrical Recording Techniques. This type of research has been used extensively in the past 40 or so years and has been instrumental in showing the time-course of stimulus processing. Possibly the most important discovery has been that the human brain often processes stimuli in our environments long before an overt response is required. D. New Scanning Techniques. PET scans the absorption of radioactivity from outside the scalp and the data is fed to a computer, which maps the activity onto a color-coded brain map, which can be observed on a monitor or as a printout.
More activity is colored red, least blue.
Sophisticated computer programs allow researchers to observe slices of the brain and therefore observe deeper brain structures like the hippocampal formation which ERP techniques are not capable of doing. This technique works on the principal of very strong magnetic fields being applied to the outside of the head which must be kept still and is therefore generally encased in a brace. This field will only become more and more sophisticated with time. Currently the machines used to measure human brain activity in situ are expensive, and typically housed in hospitals and universities. The future will see a drop in costs, a further sophistication of techniques and the day will come when scientists can observe specific brain cells one at a time as they function in the living human.