title: Functional Connectivity Substrates for tDCS Response in Minimally Conscious State Patients.
abstract: Transcranial direct current stimulation (tDCS) is a non-invasive technique recently employed in disorders of consciousness, and determining a transitory recovery of signs of consciousness in almost half of minimally conscious state (MCS) patients. Although the rising evidences about its possible role in the treatment of many neurological and psychiatric conditions exist, no evidences exist about brain functional connectivity substrates underlying tDCS response. We retrospectively evaluated resting state functional Magnetic Resonance Imaging (fMRI) of 16 sub-acute and chronic MCS patients (6 tDCS responders) who successively received a single left dorsolateral prefrontal cortex (DLPFC) tDCS in a double-blind randomized cross-over trial. A seed-based approach for regions of left extrinsic control network (ECN) and default-mode network (DMN) was performed. tDCS responders showed an increased left intra-network connectivity for regions co-activated with left DLPFC, and significantly with left inferior frontal gyrus. Non-responders (NR) MCS patients showed an increased connectivity between left DLPFC and midline cortical structures, including anterior cingulate cortex and precuneus. Our findings suggest that a prior high connectivity with regions belonging to ECN can facilitate transitory recovery of consciousness in a subgroup of MCS patients that underwent tDCS treatment. Therefore, resting state-fMRI could be very valuable in detecting the neuronal conditions necessary for tDCS to improve behavior in MCS.
authors.affiliation: Coma Science Group, GIGA-Research, University and University Hospital of LiegeLiege, Belgium; NAPLab, IRCCS SDN Istituto di Ricerca Diagnostica e NucleareNaples, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Cavaliere
authors.affiliation: NAPLab, IRCCS SDN Istituto di Ricerca Diagnostica e Nucleare Naples, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Aiello
authors.affiliation: Coma Science Group, GIGA-Research, University and University Hospital of Liege Liege, Belgium.
authors.forename: Carol
authors.initials: C
authors.lastname: Di Perri
authors.affiliation: Coma Science Group, GIGA-Research, University and University Hospital of Liege Liege, Belgium.
authors.forename: Enrico
authors.initials: E
authors.lastname: Amico
authors.affiliation: Coma Science Group, GIGA-Research, University and University Hospital of Liege Liege, Belgium.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Martial
authors.affiliation: Coma Science Group, GIGA-Research, University and University Hospital of LiegeLiege, Belgium; Spaulding Neuromodulation Center, Spaulding Rehabilitation Hospital/Harvard Medical SchoolBoston, MA, USA.
authors.forename: Aurore
authors.initials: A
authors.lastname: Thibaut
authors.affiliation: Coma Science Group, GIGA-Research, University and University Hospital of Liege Liege, Belgium.
authors.forename: Steven
authors.initials: S
authors.lastname: Laureys
authors.affiliation: Department of Physics and Astronomy, Brain and Mind Institute, Western University London, ON, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Soddu
keywords: disorders of consciousness; magnetic resonance imaging; minimally conscious state; prefrontal cortex; resting state networks; transcranial direct current stimulation