Anodal tDCS targeting the right orbitofrontal cortex enhances facial expression recognition

Abstract

The orbitofrontal cortex (OFC) has been implicated in the capacity to accurately recognise facial expressions. The aim of the current study was to determine if anodal transcranial direct current stimulation (tDCS) targeting the right OFC in healthy adults would enhance facial expression recognition, compared with a sham condition. Across two counterbalanced sessions of tDCS (i.e. anodal and sham), 20 undergraduate participants (18 female) completed a facial expression labelling task comprising angry, disgusted, fearful, happy, sad and neutral expressions, and a control (social judgement) task comprising the same expressions. Responses on the labelling task were scored for accuracy, median reaction time and overall efficiency (i.e. combined accuracy and reaction time). Anodal tDCS targeting the right OFC enhanced facial expression recognition, reflected in greater efficiency and speed of recognition across emotions, relative to the sham condition. In contrast, there was no effect of tDCS to responses on the control task. This is the first study to demonstrate that anodal tDCS targeting the right OFC boosts facial expression recognition. This finding provides a solid foundation for future research to examine the efficacy of this technique as a means to treat facial expression recognition deficits, particularly in individuals with OFC damage or dysfunction.

Keywords: emotion; facial expression recognition; mild brain stimulation; orbitofrontal cortex; transcranial direct current stimulation (tDCS).

© The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Figures

Fig. 1.

Median reaction times on the facial expression recognition task, averaged across participants, for each emotion across the anodal and sham conditions.

Fig. 2.

Mean facial expression recognition accuracy, reflected as proportion correct, for each emotion across the anodal and sham conditions.

Fig. 3.

Mean efficiency of facial expression recognition for each emotion across the anodal and sham conditions.

Fig. 4.

Mean approachability ratings for each emotion across the anodal and sham conditions.

Fig. 5.

Median reaction times on the approachability task, averaged across participants, for each emotion in both the anodal and sham conditions.