title: Widespread modulation of cerebral perfusion induced during and after transcranial direct current stimulation applied to the left dorsolateral prefrontal cortex.
abstract: Noninvasive neuromodulatory techniques such as transcranial direct current stimulation (tDCS) are attracting increasing interest as potential therapies for a wide range of neurological and psychiatric conditions. When targeted to the dorsolateral prefrontal cortex (DLPFC), anodal, facilitatory tDCS has been shown to improve symptoms in a range of domains including working memory, mood, and pain perception (Boggio et al., 2008a; Dockery et al., 2009; Kalu et al., 2012). However, the mechanisms underlying these promising behavioral effects are not well understood. Here, we investigated brain perfusion changes, as assessed using whole-brain arterial spin labeling (ASL), during tDCS applied to the left DLPFC in healthy humans. We demonstrated increased perfusion in regions closely anatomically connected to the DLPFC during anodal tDCS in conjunction with a decreased functional coupling between the left DLPFC and the thalami bilaterally. Despite highly similar effects on cortical excitability during and after stimulation (Nitsche and Paulus, 2000, 2001), cortical perfusion changes were markedly different during these two time periods, with widespread decreases in cortical perfusion being demonstrated after both anodal and cathodal tDCS compared to the period during stimulation. These findings may at least partially explain the different effects on behavior in these time periods described previously in the motor system (Stagg et al., 2011). In addition, the data presented here provide mechanistic explanations for the behavioral effects of anodal tDCS applied to the left DLPFC in terms of modulating functional connectivity between the DLPFC and thalami, as has been hypothesized previously (Lorenz et al., 2003).
authors.affiliation: Oxford Centre for Functional Magnetic Resonance Imaging of the Brain and Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom. cstagg@fmrib.ox.ac.uk
authors.forename: Charlotte J
authors.initials: CJ
authors.lastname: Stagg
authors.forename: Richard L
authors.initials: RL
authors.lastname: Lin
authors.forename: Melvin
authors.initials: M
authors.lastname: Mezue
authors.forename: Andrew
authors.initials: A
authors.lastname: Segerdahl
authors.forename: Yazhuo
authors.initials: Y
authors.lastname: Kong
authors.forename: Jingyi
authors.initials: J
authors.lastname: Xie
authors.forename: Irene
authors.initials: I
authors.lastname: Tracey
mesh_terms: D000328:Adult; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D017397:Prefrontal Cortex / Q000098:blood supply* / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D055815:Young Adult