Tuning the brakes – Modulatory role of transcranial random noise stimulation on inhibition

Background: Everyday decision-making requires the ability to flexibly modify and sometimes terminate our actions, such as avoiding a tempting slice of cake to hitting the brakes in an emergency. Neural oscillations, such as beta-band rhythms observed over the medial prefrontal cortex(mPFC), help regulate these context-dependent behaviours. However, how random noise stimulation would modulate neural rhythms and corresponding inhibitory behaviors remain understudied. Objectives: To target the mPFC using random noise stimulation and modulate neural activity underlying inhibitory behaviours. Methods: Using a single blinded within-subject design, fifteen participants received random noise or sham stimulation in a pseudo-randomized order while performing a Go/Conflict/No-Go task. We measured neural activity and behavior before and after stimulation. Results: We show that random noise stimulation significantly improved inhibitory behaviors (4.6 +/- 4.42%) by reducing the number of errors in No-Go trials. This improvement was a function of participants' impulsivity-levels and baseline performance, i.e., impulsive individuals who made more baseline errors improved more after receiving stimulation. At the neural level, we show that random noise stimulation increases low-beta power at stimulation site, mediated by an increase in the duration of intermittent beta-bursts. Conclusion: We show for the first time that random noise stimulation improves the ability to withhold response to unexpected inhibitory cues as a function of an individual's impulsivity level. This improvement could be attributed to increased low-beta band power and intermittent-burst duration. These results suggest that random noise stimulation of the mPFC could potentially be used as a neuromodulatory intervention to target maladaptive behaviors in impulse control disorders. ### Competing Interest Statement The authors have declared no competing interest.