Cerebral alteration perfusion induced by transcranial stimulation of the prefrontal cortex: a randomized, placebo-controlled study, using 99mTc SPECT

Abstract

tDCS (transcranial Direct Current Stimulation) has been extensively investigated in recent years for the treatment of mental and neurological disorders. However, studies analyzing its efficacy have presented heterogeneous results, raising questions about its application as a monotherapy treatment. On the other hand, recent research has shown that tDCS combined with other therapies is more effective than when applied by itself. Therefore, this project proposes to investigate the effects of tDCS combined with Theta-Burst Stimulation (TBS), a repetitive Transcranial Magnetic Stimulation (rTMS) technique. In this double-blind study, the combination of effects of tDCS and TBS on Dorsolateral Prefrontal Cortex (DLPFC) will be evaluated using the Single Photon Emission Computed Tomograph (SPECT) and a working memory task (n-back task). We will recruit 30 healthy subjects between 18 and 45 years old that will undergo four randomized stimulation protocols (sham tDCS + sham TBS, anodal tDCS + sham TBS, sham tDCS + active iTBS and anodal tDCS + active TBS), with one-week intervals between them. During the last nine minutes of the tDCS session, iTBS will be performed on the left DLPFC. Sequentially, an injection of technetium-99m (99mTc-ECD) will be administered and neuroimaging will be acquired within one hour of the session's end. N-back task will be applied before SPECT tomography. Our hypothesis is that there will be a difference in cerebral perfusion alterations between groups. Therefore, the protocol presenting the greatest effect, verified by the increase in cerebral perfusion and performance of working memory, can be used in further studies with psychiatric patients.In the final five minutes of each session, an injection of technetium-99m (99mTc-ECD) will be administered and neuroimaging will be acquired within one hour of the session's end. N-back task will be applied before SPECT tomography. Our hypothesis is that there will be a difference in cerebral perfusion alterations between groups. Therefore, the protocol presenting the greatest effect, verified by the increase in cerebral perfusion and performance of working memory, can be used in further studies with psychiatric patients. (AU)