Exploring the effects of anodal and cathodal high definition transcranial direct current stimulation targeting the dorsal anterior cingulate cortex

Wing Ting To,Sven Vanneste,John Hart,Justin Eroh

doi:10.1038/s41598-018-22730-x

Abstract

The dorsal anterior cingulate cortex (dACC) has been identified as a core region affected by many disorders, representing a promising target for neuromodulation. High Definition-transcranial Direct Current Stimulation (HD-tDCS) is a non-invasive neuromodulation technique that has already shown promising outcomes and has been tested to engage deeper structures. This study investigates whether it is possible to modulate dACC activity using anodal and cathodal HD-tDCS. Furthermore, it examines what effects anodal and cathodal HD-tDCS targeting dACC have on cognitive and emotional processing. Forty-five healthy subjects were randomly assigned to 1 of 3 groups: anodal, cathodal, and sham. Resting-state electroencephalography (rsEEG) and a cognitive and emotional Counting Stroop task were administered before and after HD-tDCS. RsEEG showed changes: anodal HD-tDCS showed significant increase in beta frequency band activity in dACC, while cathodal HD-tDCS led to significant increase in activity at dorsal and rostral ACC in the theta frequency band. Behavioral changes were also found after anodal HD-tDCS in the cognitive Counting Stroop for incongruent trials and after cathodal HD-tDCS in the emotional Counting Stroop for emotional trials. This study demonstrated that HD-tDCS is able to modulate dACC activity, suggesting that it has the potential to be used as a treatment tool.

Highlights

The anterior cingulate cortex has been demonstrated to be an important brain region in psychopathology as neuroimaging studies have shown dysfunctional anterior cingulate cortex activity in many neuropsychiatric disorders[1]
As the dorsal anterior cingulate cortex (dACC) is an important target for the treatment of different neurological and neuropsychiatric disorders, it is important to explore whether High Definition transcranial direct current stimulation (tDCS) (HD-tDCS) is capable of modulating this brain area
We investigated whether anodal and cathodal HD-tDCS were capable of modulating dorsal anterior cingulate cortex activity, reflected in neurophysiological and behavioral changes

Summary

Introduction

The anterior cingulate cortex has been demonstrated to be an important brain region in psychopathology as neuroimaging studies have shown dysfunctional anterior cingulate cortex activity in many neuropsychiatric disorders[1]. The dACC has deliberately been targeted using lesioning techniques (i.e. cingulotomy psychosurgery) and neuromodulation techniques (e.g. deep brain stimulation, TMS) for the treatment of various disorders, including obsessive-compulsive disorders, pain, addiction, and tinnitus (e.g. refs[7,11,12,13,19,23,50,51]). These findings point to a more general role of the dACC than involvement in cognitive processing alone. Other assessments were included in the study to control for other effects, such as anxiety (State-Trait Anxiety Inventory), general attention, and executive functions (Trail Making Tests A and B)

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