Polarity- and valence-dependent effects of prefrontal transcranial direct current stimulation on heart rate variability and salivary cortisol

Autor(es)

Brunoni, Andre R. ^{[1, 2]} ; Vanderhasselt, Marie-Anne ^[3] ; Boggio, Paulo S. ^{[4, 5]} ; Fregni, Felipe ^[6] ; Dantas, Eduardo Miranda ^[7] ; Mill, Jose G. ^[7] ; Lotufo, Paulo A. ^[1] ; Bensenor, Isabela M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Univ Hosp, Clin Res Ctr, BR-05508000 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Psychol, Dept Neurosci & Behav, BR-05508000 Sao Paulo - Brazil

^[3] Univ Ghent, Dept Expt Clin & Hlth Psychol, Ghent - Belgium

^[4] Univ Prebiteriana Mackenzie, Ctr Hlth & Biol Sci, Cognit Neurosci Lab, Sao Paulo - Brazil

^[5] Univ Prebiteriana Mackenzie, Ctr Hlth & Biol Sci, Dev Disorders Program, Sao Paulo - Brazil

^[6] Harvard Univ, Sch Med, Spaulding Rehabil Hosp, Lab Neuromodulat, Boston, MA - USA

^[7] Univ Fed Espirito Santo, Vitoria - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PSYCHONEUROENDOCRINOLOGY; v. 38, n. 1, p. 58-66, JAN 2013.
• Citações Web of Science: 45

Resumo

Recent evidence has supported the notion that the hypothalamic-pituitary-adrenal (HPA) and the sympatho-adreno-medullary (SAM) systems are modulated by cortical structures such as the prefrontal cortex. This top-down modulation may play a major role in the neuroendocrine changes associated with stressful events. We aimed to investigate further this hypothesis by modulating directly prefrontal cortex excitability using transcranial direct current stimulation (tDCS) - a non-invasive, neuromodulatory tool that induces polarity-dependent changes in cortical excitability - and measuring effects on salivary cortisol and heart rate variability as proxies of the HPA and SAM systems. Twenty healthy participants with no clinical and neuropsychiatric conditions were randomized to receive bifrontal tDCS (left anodal/right cathodal or left cathodal/right anodal) or sham stimulation, in a within-subject design. During each stimulation session, after a resting period, subjects were shown images with neutral or negative valence. Our findings showed that excitability enhancing left anodal tDCS induced a decrease in cortisol levels. This effect is more pronounced during emotional negative stimuli. Moreover, vagal activity was higher during left anodal tDCS and emotional negative stimuli, as compared to sham stimulation and neutral images. We also observed an association between higher mood scores, higher vagal activation and lower cortisol levels for anodal stimulation. Subjective mood and anxiety evaluation revealed no specific changes after stimulation. Our findings suggest that tDCS induced transient, polarity specific modulatory top-down effects with anodal tDCS leading to a down-regulation of HPA and SAM systems. Further research using tDCS and neuroendocrine markers should explore the mechanisms of stress regulation in healthy and clinical samples. (C) 2012 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 10/10797-5 - Variabilidade da frequência cardíaca e do cortisol salivar em voluntários saudáveis submetidos à estímulos visuais negativos e neutros, antes e após estimulação transcraniana por corrente contínua
• Beneficiário: Isabela Judith Martins Bensenor
• Modalidade de apoio: Auxílio à Pesquisa - Regular