Inverse effects of tDCS over the left versus right DLPC on emotional processing: A pupillometry study

• Published in: PloS one Vol. 14; no. 6; p. e0218327
• Main Authors: Allaert, Jens, Sanchez-Lopez, Alvaro, De Raedt, Rudi, Baeken, Chris, Vanderhasselt, Marie-Anne
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 19.06.2019; Public Library of Science (PLoS)
• Subjects: Adult; Affect - physiology; Affect - radiation effects; Antidepressants; Attention - physiology; Attentional bias; Biology and Life Sciences; Brain; Clinical psychology; Cognition; Cognition - physiology; Cognitive ability; Dilation; Direct current; Effects; Electrical stimulation of the brain; Emotions; Emotions - physiology; Emotions - radiation effects; ESB; Female; Health psychology; Healthy Volunteers; Hemispheric laterality; Humans; Male; Medicine and Health Sciences; Mental depression; Movement disorders; Neurosciences; Physical Sciences; Prefrontal cortex; Prefrontal Cortex - physiopathology; Prefrontal Cortex - radiation effects; Psychiatry; Pupillometry; Research and Analysis Methods; Resource allocation; Social exclusion; Social Sciences; Stimulation; Stimuli; Transcranial Direct Current Stimulation - methods; Belgium
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0218327

The Dorsolateral prefrontal cortex (DLPFC) is implicated in cognitive and emotional responses. Yet, research that investigates the causal role of the left versus right DLPFC during the processes of emotion appraisal is lacking. In the current study, transcranial direct current stimulation (tDCS) was used to disentangle the functional lateralization of the DLPFC on emotional processing in response to the anticipation of, and subsequent confrontation with emotional stimuli in healthy volunteers. Forty-eight subjects received both active and sham (on separate days) anodal tDCS over either the left (N = 24) or right (N = 24) DLPFC. Subjects' pupil dilation (PD, a physiological marker of cognitive resource allocation) was recorded while performing an appraisal task in which negative and positive emotion eliciting images were presented, each preceded by an informative cue indicating the valence of the upcoming stimulus. As compared to sham stimulation, left DLPFC anodal tDCS resulted in increased PD when confronted with negative emotional images, whereas right DLPFC anodal tDCS resulted in decreased PD when confronted with emotional images, irrespective of valence. The interpretation of pupil dilation in response to emotional stimuli is limited. These findings suggest inverse lateralized DLPFC effects on cognitive resource allocation (as measured by pupillary responses) when confronted with emotional stimuli. The current findings may shed some light on mechanisms that explain the antidepressant effects of non-invasive brain stimulation of the left DLPFC.