Research

Error processing in the human brain

Our laboratory is interested in what happens in the brain when people make errors. How does the brain detect the error, and how does it then adjust its strategies and behavior to reduce the likelihood of future errors?

Our lab focuses on an electrophysiological measure of error processing known as the error-related negativity (ERN). The ERN is evident as a large negative polarity peak in the event-related brain potential waveform that occurs when people make errors in reaction time tasks. It begins at the moment of the error and reaches a maximum about 100 milliseconds later (see Gehring et al., 1993, 1995). It is largest at fronto-central scalp locations and appears to come from an area of the brain called the anterior cingulate cortex (Dehaene, Posner, & Tucker, 1994).

A number of studies have suggested that the ERN reflects the activity of a brain system that detects and corrects for errors. We suggested that this activity was probably generated by the anterior cingulate cortex. Later studies, using a technique for modeling the intracranial sources of ERPs, supported this claim (Dehaene, Posner, & Tucker, 1994).  What the brain is doing 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. 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 a dopaminergic negative reinforcement learning signal that happens when outcomes occur that are "worse than expected" (Holroyd and Coles, 2002).

There are thus many unresolved questions:    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 compensate for the error? What is the role of expectancy in generating the activity?

Action Monitoring Dysfunctions in OCD

Theories of Obsessive-Compulsive Disorder assert that individuals with OCD have "hyperactive error signals" telling them that there is a conflict between their internal standards and what is happening in the world (Schwartz, 1997). The person performs corrective actions repetitively to reduce the error signals. Anterior cingulate hyperactivity is also implicated in OCD. Based on these ideas, we predicted that individuals with OCD would show more ERN activity than individuals without the disorder. I and my collaborators from the U of M Psychiatry Department Anxiety Disorders Clinic (see Gehring, Himle, & Nisenson, 2000) confirmed this prediction: ERN activity was enhanced in the individuals with OCD compared with controls. Furthermore, the magnitude of this enhancement correlated with the severity of OCD symptoms, as assessed by the Yale-Brown Obsessive-Compulsive Scale. The localization of the activity was consistent with an anterior cingulate generator. These data suggest that excessive anterior cingulate action monitoring activity is associated with the symptoms of OCD. We have continued to follow up this line of research, using functional magnetic resonance imaging (fMRI). Like ERP measures, the fMRI measures show a hyperactivity in the anterior cingulate that correlates with symptom severity (see Fitzgerald, Welsh, Gehring, Abelson, Himle, Liberzon, & Taylor, 2005).

Monetary Gains and Losses

As research on the ERN has progressed, a number of findings have pointed to a different interpretation of the ERN. Don Tucker and Phan Luu and their colleagues, for example , found that ERN-like activity can be observed when people encounter events associated with negative emotions, and they also found that people who score high in negative emotionality produce larger ERNs than control subjects early in task performance. John Allen has found that individuals who score low on measures of socialization (as do psychopaths) show reduced ERNs when punished for errors, consistent with psychopaths' inability to stop doing things for which they are punished. A number of other findings have seemed inconsistent with the response-conflict and error-detection views.

Findings like these led us to hypothesize that the anterior cingulate is involved in detecting motivationally salient negative events. Clay Holroyd and his colleagues have proposed a similar view, emphasizing the role of midbrain dopaminergic systems in generating a response to outcomes that are worse than expected. One example of such an event is the loss of money in a gambling task. We found that losses in a simple gambling task would be were associated with activity similar to the ERN (see Gehring & Willoughby, 2002), even when the subjects made a correct choice (by avoiding other, worse losses).

 

Current Studies

In our current work, we are pursuing several lines of work, including

1) Dysfunctions of error processing in childhood obsessive-compulsive disorder.

2) How the electrophysiological and fMRI measures of anterior cingulate dysfunction are related.

3) The relationship between the perceptual properties of feedback stimuli and the size and timing of the feedback-related negativity.

4) The development of executive control in children during the age of transition to kindergarten.

5) The role of medial frontal ERN-like activity in visuomotor adapation in simple aimed movements.

 

Other References

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.

Schwartz, J.M. (1997). Cognitive-behavioral self-treatment for obsessive-compulsive disorder systematically alters cerebral metabolism: A mind-brain interaction paradigm for psychotherapists. In Obsessive-Compulsive Disorders: Diagnosis, Etiology, Treatment. Eds E. Hollander & D.J. Stein, pp. 257-281. New York: Marcel Dekker.