The brain runs on electrical and chemical activity, and some of the electrical activity is conducted through the brain and the skull and up to the scalp, where it can be recorded using electrodes. Researchers have identified a number of event-related potentials -- brain waves -- that occur when the brain engages in specific mental processes. Our lab focuses on one of these brain waves known as the error-related negativity (ERN). The ERN is a large negative polarity waveform that occurs when people make errors. It is usually seen when people are trying to be fast -- like when they are typing or trying to respond quickly to events on the screen (as might happen in a video game). The ERN itself is fast: it begins at the moment of the error and peaks within about 100 milliseconds later (see Gehring et al., 1993, 1995). It is largest in the middle of the scalp, close to the front, and it appears to come from an area of the brain called the anterior cingulate cortex (Dehaene, Posner, & Tucker, 1994).
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Many studies have suggested that the ERN reflects the activity of a brain system that detects and corrects for errors. In our early work, we suggested that this activity was probably generated by the anterior cingulate cortex (Gehring, Goss, Coles, Meyer and Donchin, 1993). Later studies supported this, using a technique for localizing ERPs (Dehaene, Posner, & Tucker, 1994). What exactly brain is trying to accomplish when it generates an ERN is still a very active area of investigation. Some investigators have argued that the anterior cingulate (and any cingulate activity reflected by the ERN) reflects the detection of response conflict, rather than errors per se. The idea is that your brain knows that it is doing something wrong simply because it is trying to do two incompatible things at the same time. A more recent view is that the brain detects motivationally or emotionally salient events, especially negative ones, and that errors are simply one of many possible events that can elicit ERN-like activity. One variant of this view is that the ERN reflects dopamine, specifically a dopaminergic negative reinforcement learning signal that happens when outcomes occur that are "worse than expected" (Holroyd and Coles, 2002). And there are other new theories emerging every year.Does the ERN reflect an error detection process? Does it reflect an affective/emotional response to the error? Does the outcome of the processing help guide emotional or cognitive systems to correct the error and make adjustments so that errors are less likely in the future? What is the role of expectancy in generating the activity? You can read more about this in our papers. For some excellent work by other labs, see also: Dehaene, S., Posner, M. I., & Tucker, D. M. (1994). Localization of a neural system for error detection and compensation. Psychological Science, 5, 303-305. Holroyd, C. B, & Coles, M. G. H. (2002). The neural basis of human error processing: Reinforcement learning, dopamine, and the error-related negativity. Psychological Review, 109, 679-709.