title: Resting-state fMRI reveals enhanced functional connectivity in spatial navigation networks after transcranial direct current stimulation.
abstract: A number of studies have established that transcranial direct current stimulation (tDCS) modulates cortical excitability. We previously demonstrated polarity dependent changes in parietal lobe blood oxygen level dependent (BOLD) fMRI in a group of young adults during a spatial navigation task [15]. Here we used resting state functional connectivity (rsFC) to examine whether analogous changes were also evident during the resting state. Participants were randomized to either a parietal-anodal, frontal-cathodal (P+F-) or the opposite montage (P-F+) and received 20min of tDCS (2mA) before undergoing resting-state fMRI. rsFC was evaluated between the groups by placing a seed in the medial superior parietal lobule (mSPL), which was under the target electrode. rsFC between the mSPL and a number of other areas involved in spatial navigation, scene processing, and sensorimotor processing was significantly higher in the P+F- than the P-F+ group. Thus, the modulatory effects of tDCS were evident during rest and suggest that stimulation primes not just the underlying neocortex but an extended network that can be recruited as necessary during active task performance.
authors.affiliation: Department of Radiology & Imaging Sciences, Emory University, Atlanta, GA, USA.
authors.forename: Venkatagiri
authors.initials: V
authors.lastname: Krishnamurthy
authors.affiliation: Department of Radiology & Imaging Sciences, Emory University, Atlanta, GA, USA. Electronic address: kaundinya.s.gopinath@emory.edu.
authors.forename: Kaundinya
authors.initials: K
authors.lastname: Gopinath
authors.affiliation: Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Brown
authors.affiliation: Rehabilitation R&D Center of Excellence, Atlanta VAMC, Decatur, GA, USA; Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Hampstead
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011897:Random Allocation; D012146:Rest; D065854:Spatial Navigation; D065908:Transcranial Direct Current Stimulation
keywords: Cortical excitability; Functional connectivity; Resting state networks; Spatial navigation; fMRI; tDCS