Maria Ironside1, Jacinta O'Shea2, Philip J Cowen3, Catherine J Harmer3. 1. Department of Psychiatry, University of Oxford, Oxford, United Kingdom. Electronic address: maria.ironside@psych.ox.ac.uk. 2. Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom. 3. Department of Psychiatry, University of Oxford, Oxford, United Kingdom.
Abstract
BACKGROUND: The difficulty in treating mood disorders has brought about clinical interest in alternative treatments, such as transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC). However, the optimal parameters for stimulation and underlying mechanisms of action are unclear. Psychiatric treatments have acute effects on emotional processing that predict later therapeutic action. Such effects have been proposed as cognitive biomarkers for screening novel treatments for depression and anxiety. METHODS: This study assessed the effect of tDCS on a battery of emotional processing measures sensitive to antidepressant action. To refine optimal stimulation parameters, DLPFC stimulation using two common electrode montages was compared with sham. Sixty healthy volunteers received 20 minutes of active or sham DLPFC stimulation before completing computerized emotional processing tasks, including a dot-probe measure of vigilance to threat. RESULTS: Relative to sham stimulation, participants receiving simultaneous anodal stimulation of left DLPFC and cathodal stimulation of right DLPFC (bipolar-balanced montage) showed reduced vigilance to threatening stimuli. There was no such significant effect when the cathode was placed on the supraorbital ridge (bipolar-unbalanced montage). There were no effects of tDCS on other measures of emotional processing. CONCLUSIONS: Our findings provide the first experimental evidence that modulating activity in the DLPFC reduces vigilance to threatening stimuli. This significant reduction in fear vigilance is similar to that seen with anxiolytic treatments in the same cognitive paradigm. The finding that DLPFC tDCS acutely alters the processing of threatening information suggests a potential cognitive mechanism that could underwrite treatment effects in clinical populations.
RCT Entities:
BACKGROUND: The difficulty in treating mood disorders has brought about clinical interest in alternative treatments, such as transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC). However, the optimal parameters for stimulation and underlying mechanisms of action are unclear. Psychiatric treatments have acute effects on emotional processing that predict later therapeutic action. Such effects have been proposed as cognitive biomarkers for screening novel treatments for depression and anxiety. METHODS: This study assessed the effect of tDCS on a battery of emotional processing measures sensitive to antidepressant action. To refine optimal stimulation parameters, DLPFC stimulation using two common electrode montages was compared with sham. Sixty healthy volunteers received 20 minutes of active or sham DLPFC stimulation before completing computerized emotional processing tasks, including a dot-probe measure of vigilance to threat. RESULTS: Relative to sham stimulation, participants receiving simultaneous anodal stimulation of left DLPFC and cathodal stimulation of right DLPFC (bipolar-balanced montage) showed reduced vigilance to threatening stimuli. There was no such significant effect when the cathode was placed on the supraorbital ridge (bipolar-unbalanced montage). There were no effects of tDCS on other measures of emotional processing. CONCLUSIONS: Our findings provide the first experimental evidence that modulating activity in the DLPFC reduces vigilance to threatening stimuli. This significant reduction in fear vigilance is similar to that seen with anxiolytic treatments in the same cognitive paradigm. The finding that DLPFC tDCS acutely alters the processing of threatening information suggests a potential cognitive mechanism that could underwrite treatment effects in clinical populations.
Authors: Mascha van 't Wout; Timothy Y Mariano; Sarah L Garnaat; Madhavi K Reddy; Steven A Rasmussen; Benjamin D Greenberg Journal: Brain Stimul Date: 2016-03-09 Impact factor: 8.955
Authors: Maria Ironside; Michael Browning; Tahereh L Ansari; Christopher J Harvey; Mama N Sekyi-Djan; Sonia J Bishop; Catherine J Harmer; Jacinta O'Shea Journal: JAMA Psychiatry Date: 2019-01-01 Impact factor: 21.596
Authors: Timothy Y Mariano; Mascha Van't Wout; Sarah L Garnaat; Steven A Rasmussen; Benjamin D Greenberg Journal: Pain Med Date: 2015-12-11 Impact factor: 3.750