It is clear that mistakes are somehow registered and processed in the brain. This is because errors result in behavior-based reactions such as moving to correct them and slowing down slightly while working so as not to risk making them again. As the links between such observations or perceptions are made in the brain, it follows that this organ controls the recognition and responses to errors in the people who make them.
Mistakes and the Brain
Scientists have never precisely identified the actual brain tissue in which these functions take place. This knowledge would be vital in some areas of medicine and psychiatry, as it may be extremely relevant to conditions such as obsessive-compulsive disorder (OCD).
Currently, some researchers hypothesize that these brain regions may be overactive or abnormally active in cases of OCD, causing the affected patients to perceive errors or the potential for error in many things that they do on a daily basis. This, in turn, could lead to the repetitive, pathological ‘rituals’ that affect the lives of many patients with OCD today.
Conversely, some other health states are characterized by the reduced or absent ability to detect or respond to errors at all. These conditions include schizophrenia and possibly some other, similar psychiatric disorders.
Based on the functions and connections between them, it is thought that some sub-regions of the medial frontal cortex (MFC) and the motor areas of the brain may be closely related to error processing. This is because these areas are associated with impulses that facilitate the manipulation of the environment and the coordination of the actions that facilitate this. However, scientists have only had a few opportunities to test their theories.
The rough location of the relevant brain area, within the MFC, related to error recognition. (Source: Public Domain)
Zooming in on Error Recognition in the MFC
The MFC and the motor regions are already broadly associated with error recognition through studies based on electroencephalography (EEG) data. The use of the non-invasive technique has resulted in the detection of specific brain activity associated with the identification of an error in the course of a task. The more precise location of this activity, or error-related negativity (ERN) as it is known, would require the analysis of data derived from more direct, and more invasive, ‘readings’ taken from electrode planted directly in the brain.
Obviously, direct-brain implantations for the purposes of one study is a rather disproportional imposition on potential participants and, most probably, would not be sanctioned by any functional institutional ethics committee.
However, a group of researchers working at the California Institute of Technology and Cedars-Sinai Medical Center in Los Angeles found that they had a much more acceptable, fortuitous, opportunity to study the MFC and its motor connections in this manner.
It arose from a group of patients who had consented to temporary electrode implantation in these brain regions in order to study and model their severe epilepsy, in detail, to plan long-term treatment plans for them. Epilepsy is a condition that may involve the frontal and motor cortices, but not error-recognition or processing.
Therefore, the Caltech/Cedars-Sinai group, led by Dr. Adam Mamelak, a professor of neurosurgery at Cedars-Sinai, secured consent from the same group of patients to perform error-recognition neurological tests while the electrodes were still in place.
The Discovery of Error Neurons
These study participants completed the Stroop test. It involved a task where the subjects were required to look at images in which the name of a color, in clear, readable text, was printed in a second color. The general aim of the Stroop test is to call out this second color, and not the name of the one spelled out in the text. The failure to do so has been associated with EEG recordings indicating error-recognition neurons (ERNs) in the past.
The basic goal of the Stroop test is to call out the colors in which the words are printed, and not the color names, in both halves of this image. (Source: Xiaozhu89/Wikipedia)
The Caltech/Cedars-Sinai team found that ERNs were indeed reproducibly evinced in response to ‘misses’ in the course of the Stroop tests.
The researchers were able to use the electrode data not merely to trace the ERNs back to specific parts of the MFC and the pre-supplemental motor area (pSMA), but to specific single neurons in these regions too.
These neurons were found in the dorsal anterior cingulate cortex (dACC) and pSMA and were designated ‘error neurons’ by the team. These neurons were found to fire first in the pSMA in response to a Stroop-test miss, and then in the dACC about 50 milliseconds later.
This could suggest that the motor-related ‘error neurons’ are the first to ‘realize’ that an error-related behavior has been committed, which is then ‘logged’ by the dACC neurons. This is possibly done to modulate or refine future behavioral impulses so that they may not occur again in the future. Such a possibility is correlated by the additional detection of ‘error-history’ neurons, which were also located in the dACC. Their activity, which increased in response to error-neuron firing, was found to predict the behavioral response of post-error slowing, as the team analyzed their data.
These potentially important findings may now inform the future directions of research into treatments for conditions such as OCD.
The team has published this research in the Cell Press journal, Neuron.
The researchers now also say that their work may enhance the understanding of other, relevant brain processes such as memory, cognition and behavioral self-regulation in certain situations and the future of their study.
Top Image: Mistakes are easy to make, and they need action to correct. (Source: Bernswaelz/Pixabay)
References
'Error Neurons' play role in how brain processes mistakes, 2018, EurekAlert, https://www.eurekalert.org/pub_releases/2018-12/cmc-np120418.php, (accessed 12 Dec. 18)
Z. Fu, et al. (2018), Single-Neuron Correlates of Error Monitoring and Post-Error Adjustments in Human Medial Frontal Cortex, Neuron
W. H. Alexander, et al. (2011), Medial prefrontal cortex as an action-outcome predictor, Nat Neurosci, 14 (10), Pp 1338-1344
F. Bonini, et al. (2014), Action monitoring and medial frontal cortex: leading role of supplementary motor area, Science, 343 (6173), Pp 888-891
M. Brázdil, et al. (2005), Intracerebral error-related negativity in a simple go/nogo task, Journal of Psychophysiology, 19 (4), Pp 244-255
B. Burle, et al. (2008), Error negativity does not reflect conflict: a reappraisal of conflict monitoring and anterior cingulate cortex activity, J Cogn Neurosci, 20 (9), Pp 1637-1655
M. J. Frank, et al. (2005), Error-related negativity predicts reinforcement learning and conflict biases, Neuron, 47 (4), Pp 495-501
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