A simultaneous modulation of reactive and proactive inhibition processes by anodal tDCS on the right inferior frontal cortex.

Toni Cunillera,Debora Brignani,David Cucurell,Lluís Fuentemilla,Carlo Miniussi,Alessio Avenanti

doi:10.1371/journal.pone.0113537

Abstract

Proactive and reactive inhibitory processes are a fundamental part of executive functions, allowing a person to stop inappropriate responses when necessary and to adjust performance in in a long term in accordance to the goals of a task. In the current study, we manipulate, in a single task, both reactive and proactive inhibition mechanisms, and we investigate the within-subjects effect of increasing, by means of anodal transcranial direct current stimulation (tDCS), the involvement of the right inferior frontal cortex (rIFC). Our results show a simultaneous enhancement of these two cognitive mechanisms when modulating the neural activity of rIFC. Thus, the application of anodal tDCS increased reaction times on Go trials, indicating a possible increase in proactive inhibition. Concurrently, the stop-signal reaction time, as a covert index of the inhibitory process, was reduced, demonstrating an improvement in reactive inhibition. In summary, the current pattern of results validates the engagement of the rIFC in these two forms of inhibitory processes, proactive and reactive inhibition and it provides evidence that both processes can operate concurrently in the brain.

Highlights

A key aspect of executive functions is behavioral inhibition, the ability to control inappropriate or unwanted responses [1]
Anodal transcranial direct current stimulation (tDCS) slowed down the reaction times (RTs) on Go trials, and this result was accompanied by a significant reduction in commission errors when the discriminability of stimuli was easy, a significant interaction discriminability per tDCS-session did not reach statistical significant levels
The major contribution of the current study is to show the simultaneous enhancement and interrelation of these two traditionally separated cognitive mechanisms when modulating the neural activity of right inferior frontal cortex (rIFC)

Summary

Introduction

A key aspect of executive functions is behavioral inhibition, the ability to control inappropriate or unwanted responses [1]. This ability constitutes the basis of PLOS ONE | DOI:10.1371/journal.pone.0113537. There are many situations requiring to stop a specific response or to move in a controlled fashion. We can eat slowly in an etiquette dinner, even though being ‘‘famished’’, and we can even react and stop eating if somebody asks us to do it or if we perceive a strange taste or smell in the food. A better understanding of the underlying cognitive processes and its neural substrates would be the key to furthering the knowledge of this field and developing clinical treatments

Methods

Discussion

Conclusion