eprintid: 10060937 rev_number: 31 eprint_status: archive userid: 608 dir: disk0/10/06/09/37 datestamp: 2018-11-08 09:04:31 lastmod: 2021-12-06 00:22:55 status_changed: 2019-02-20 15:01:37 type: article metadata_visibility: show creators_name: Li, LM creators_name: Violante, IR creators_name: Leech, R creators_name: Ross, E creators_name: Hampshire, A creators_name: Opitz, A creators_name: Rothwell, JC creators_name: Carmichael, DW creators_name: Sharp, DJ title: Brain state and polarity dependent modulation of brain networks by transcranial direct current stimulation ispublished: pub divisions: UCL divisions: B02 divisions: C07 divisions: D07 divisions: F84 divisions: D13 keywords: default mode network, magnetic resonance imaging, salience network, stimulation note: This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. abstract: Despite its widespread use in cognitive studies, there is still limited understanding of whether and how transcranial direct current stimulation (tDCS) modulates brain network function. To clarify its physiological effects, we assessed brain network function using functional magnetic resonance imaging (fMRI) simultaneously acquired during tDCS stimulation. Cognitive state was manipulated by having subjects perform a Choice Reaction Task or being at "rest." A novel factorial design was used to assess the effects of brain state and polarity. Anodal and cathodal tDCS were applied to the right inferior frontal gyrus (rIFG), a region involved in controlling activity large-scale intrinsic connectivity networks during switches of cognitive state. tDCS produced widespread modulation of brain activity in a polarity and brain state dependent manner. In the absence of task, the main effect of tDCS was to accentuate default mode network (DMN) activation and salience network (SN) deactivation. In contrast, during task performance, tDCS increased SN activation. In the absence of task, the main effect of anodal tDCS was more pronounced, whereas cathodal tDCS had a greater effect during task performance. Cathodal tDCS also accentuated the within-DMN connectivity associated with task performance. There were minimal main effects of stimulation on network connectivity. These results demonstrate that rIFG tDCS can modulate the activity and functional connectivity of large-scale brain networks involved in cognitive function, in a brain state and polarity dependent manner. This study provides an important insight into mechanisms by which tDCS may modulate cognitive function, and also has implications for the design of future stimulation studies. date: 2019-02-15 date_type: published official_url: https://doi.org/10.1002/hbm.24420 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1599432 doi: 10.1002/hbm.24420 lyricists_name: Carmichael, David lyricists_name: Rothwell, John lyricists_id: DWCAR66 lyricists_id: JCROT52 actors_name: Cuccu, Clara actors_id: CCCUC40 actors_role: owner full_text_status: public publication: Human Brain Mapping volume: 40 number: 3 pagerange: 904-915 event_location: United States issn: 1097-0193 citation: Li, LM; Violante, IR; Leech, R; Ross, E; Hampshire, A; Opitz, A; Rothwell, JC; ... Sharp, DJ; + view all <#> Li, LM; Violante, IR; Leech, R; Ross, E; Hampshire, A; Opitz, A; Rothwell, JC; Carmichael, DW; Sharp, DJ; - view fewer <#> (2019) Brain state and polarity dependent modulation of brain networks by transcranial direct current stimulation. Human Brain Mapping , 40 (3) pp. 904-915. 10.1002/hbm.24420 <https://doi.org/10.1002/hbm.24420>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10060937/7/Carmichael%20VoR%20Li_et_al-2019-Human_Brain_Mapping.pdf