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Lecture Notes

Also, in the book, we talk about evoked potentials. Evoked potentials, or EPs, are small, temporary changes in the EEG recordings following a discreet event in the environment. So again, if we go back to that example of being presented a visual stimulus on the screen, cognitive psychologists might be looking at these evoked potentials when those stimuli are presented. And they're interested in two different kinds of EPs, one is the N100; this is a negative voltage direction. It occurs at about 100 milliseconds after the stimulus is presented. This is when the brain's primary sensory cortex receives and processes sensory characteristics of an environmental stimulus, in other words, sensation. So we can understand, kind of, when sensation is taking place by looking at these evoked potentials.