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Researchers use TDCS to affect error-monitoring behaviour (video)

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A research group from Vanderbilt University has recently published a paper demonstrating that Transcranial Direct Current Stimulation (TDCS) of Middle Frontal Cortex (MFC) can bi-directionally affect performance on an association learning task. In other words, the researchers found a correlation between certain stimulation parameters and the amount of time it took individuals to learn a simple task.In order to test whether or not stimulating MFC affects learning, the researchers had participants learn the association between one of two colours displayed on a computer screen and one of two buttons. Whenever a colour was displayed on the screen, participants had to click a button. They then got feedback about whether or not the button they pressed corresponded to the colour that had been displayed.

Based on this feedback, they had to decide which button to press when the next colour was displayed. This task was performed with and without 20 minutes of TDCS. Additionally, it was performed with anodal TDCS and cathodal TDCS.

TDCS involves running current through two electrodes (the ‘cathode’ and the ‘anode’). However, the current between them can be run in either direction. This switch in direction has been shown to have different effects on the brain. Specifically, individuals generally show increased neural activity for current running in one direction, and decreased neural activity for current running in the opposite direction.

The experiment took advantage of this fact to show that increasing neural activity in the MFC increases the likelihood that participants will choose the correct button after receiving incorrect feedback and decreasing activity decreases this liklihood.

Robert Reinhart applies the electrical stimulus to subject Laura McClenahan. After 20 minutes the headband is removed and the EEG cap will capture readings of her brain as she executes the learning task. (John Russell / Vanderbilt University)
Robert Reinhart applies the electrical stimulus to subject Laura McClenahan. After 20 minutes the headband is removed and the EEG cap will capture readings of her brain as she executes the learning task. (John Russell / Vanderbilt University)

This increase/decrease of neural activity was measured using Elecroencephalography (EEG). Specifically, the researchers used a characteristic EEG signal that is observed during “error monitoring.” This signal has been shown to be more prevalent when individuals use feedback in order to modify their behaviour in some way. In this case, it would be a matter of whether or not they used the “correct/incorrect” feedback to press the correct button when the next colour was displayed.

It is important to realize that this finding is, as of yet, only preliminary. This is far from being a “thinking cap” unless your only goal is to learn simple associations slightly more quickly. Everyone in the experiment was able to learn the association, so it’s certainly not the case that this technology will allow you to learn things you couldn’t have learned otherwise.

Additionally, it is important to remember that this is not a treatment for anything, and that the long term risks of TDCS are still not known.

However, it might suggest that something like the Foc.Us headset, if placed correctly and used responsibly, could give you ever so slight an edge in some aspects of video game performance.

Sources:
ncbi.nlm.nih.gov
vanderbilt.edu