Single neurons responsible for error detection and adjustment found

By Rajaneesh K Gopinath, Ph.D.

A collaborative study involving researchers from Caltech and Cedars-Sinai Medical Center map the single neurons in the medial frontal cortex (MFC) of the brain that performs error self-monitoring.

To err is human but learning from past mistakes is one of the specialties of our brain. At times, this error recognition happens quite rapidly and results in behavioral adjustments that either rectifies it immediately or slows down a subsequent action to prevent the risk of a repeat. Previous explorations have identified the human medial frontal cortex to be the region that governs error monitoring but a new study has discovered for the first time, the single neurons that is responsible for this function. This finding would prove useful in understanding many psychiatric disorders such as Obsessive-Compulsive Disorder (OCD) and Schizophrenia which fall on opposite sides of the error recognition spectrum. Patients affected by the former worry about committing an error and perform repetitive rituals to guard against it while the latter is a condition where errors are not detected.

Stroop Task

The goal of the study was to map the neurons that showed activity when individuals recognize their errors, as quickly as they made it. To this end, the subjects of this study were implanted with thin electrodes and were asked to complete a color-naming Stroop task. In this test, subjects were presented with a computer screen that displayed names of colors and was asked to identify the color in which a word is printed and ignore what the word means. For instance, if the word “red” is printed in blue ink, the subjects will have to say blue to register a correct answer but saying red is an error.

Conclusions from the study

The readings revealed the presence of specific neurons called “error neurons” that gets activated when subjects self-recognized their errors. The error neurons were present in two different areas of the MFC, the dorsal anterior cingulate cortex (dACC) and the pre-supplementary motor area (pre-SMA). The activity of these neurons correlated positively with another standard error-related pattern of brainwave in the MFC, called the error-related negativity (ERN). This correlation could be used to predict whether an individual would adjust their behavior in response to the error they made.

The neurons in the pre-SMA preceded the ones in the dACC by a few milliseconds in registering error signals and they were of higher amplitudes. More importantly, it was found that these error neurons were distinct from the conflict neurons, that signal when an individual makes a mistake with their first response and then takes steps to correct it. The results of this collaborative study are published in the journal Neuron and has large implications in fathoming how the brain operates while learning from mistakes and how these neurons could be manipulated to treat patients.

References

1. https://www.sciencedirect.com/science/article/pii/S0896627318310079?via%3Dihub
2. https://www.eurekalert.org/pub_releases/2018-12/cmc-np120418.php
3. https://www.sciencedaily.com/releases/2018/12/181205171910.htm

Author

Rajaneesh K. Gopinath