Brain perfusion alterations induced by standalone and combined non-invasive brain stimulation over the dorsolateral prefrontal cortex

Abstract

Abstract Non-invasive brain stimulation (NIBS) interventions are promising for the treatment of psychiatry disorders. Notwithstanding, the mechanisms of action of NIBS over the dorsolateral prefrontal cortex (DLPFC), a hub that modulates affective and cognitive processes, have not been completely mapped. We aimed to investigate regional cerebral blood flow (rCBF) changes over the DLPFC and the interconnected subgenual anterior cingulate cortex (sgACC) of different NIBS protocols using a Single Photon Emission Computed Tomography (SPECT). Twenty-three healthy subjects were allocated to randomly undergo four sessions of NIBS applied once a week: transcranial direct current stimulation (tDCS), intermittent theta-burst stimulation (iTBS), combined tDCS+iTBS and placebo. The radiotracer 99m-Technetium-ethylene-cysteine-dimer (99m-ECD) was injected intravenously during the NIBS session, and SPECT images were acquired after the session. Results revealed none of the active interventions changing rCBF on the targeted DLPFC, but the combination tDCS+iTBS increased rCBF on the right sgACC. TDCS respectively increased and decreased rCBF on DLPFC sub-regions under the cathode and anode, while iTBS did not show any significant changes compared to placebo. Our findings encourage future clinical trials combining tDCS+iTBS for psychiatric population and mechanistic studies to investigate the effects of tDCS and iTBS over the DLPFC. Research Category and Technology and Methods Basic Research: 9. Transcranial Direct Current Stimulation (tDCS)