An EEG cap allows researchers and clinicians to monitor the minute electrical activity that reaches the surface of the scalp from post-synaptic potentials in neurons, which fluctuate in relation to cognitive processing.
[1] Past research focused on the N200 as a mismatch detector, but it has also been found to reflect executive cognitive control functions, and has recently been used in the study of language (Folstein & Van Petten, 2008; Schmitt, Münte, & Kutas, 2000).
The N2 component starts with the discovery of EEG which dates back as early as 1929 with Hans Berger demonstrating the ability to record electrical activity of the brain by simply placing electrodes over the scalp and then amplifying the signal.
One of the first experiments to find evidence of an N200 was by Sutton, Braren, and Zubin (1965) [2] when examining the effects of stimulus uncertainty on sensory potentials.
Following the experiment by Sutton et al. (1965), subsequent research further manipulated stimulus uncertainty in an attempt to elicit a more robust N200.
The N200 in response to attended or unattended deviant auditory stimuli, similar to what was originally seen in Sutton et al. (1965), is referred to as the mismatch negativity.
Since the go/no-go paradigm with N200 can be used to indicate the timing of information noting, it is a good candidate to examine the order of language processing and production.
Schmitt et al. (2000)[8] utilized the occurrence of N200 in the go/no-go paradigm to determine the timing of semantic and phonological information processing.
This is one reason why the P3 and the N2 are often researched together, since they are both sensitive to similar manipulations and represent a connection of mental mechanisms that work together to interpret the changing environment.
[1] During a stop signal task the frontocentral N2 is sensitive to time pressure, in that when individuals are asked to respond as quickly as possible the amplitude of the N2 increases.
This increase in amplitude is larger within individuals who have what is considered a fast stop signal reaction time and thus who are able to inhibit a prepotent response very quickly.