Functional Connectivity Of Thalamo-Cortical Tricore Networks Based On Transcranial Direct Current Stimulation

Transcranial direct current stimulation(tDCS),as a non-invasive brain stimulation treatment,has been widely used to improve the adjunctive treatment of traumatic brain injury,schizophrenia,depression and other neuropsychiatric disorders.However,the neuromodulation mechanism of tDCS intervention remains largely unknow.The Default Mode Network(DMN),Central Executive Network(CEN)and Salience Network(SN)are the core neural cognitive networks that maintain normal cognitive function,and connection disorder between these three networks may be the neuropathological basis of many cognitive disorders.In summary,this study combined multichannel tDCS and functional magnetic resonance imaging to explore the modulation of connectivity patterns between different brain networks by tDCS under network targeting using functional connectivity and modulation effect analysis.Fifty-nine healthy participants were recruited in the current study,each of whom received two types of tDCS: a network-based tDCS targeting Sensorimotor Network(SMN-tDCS)and also received DMN-targeted as a control.Firstly,Sim NIBS was used to simulate the electric field of two different configurations of NB-tDCS for each participant,and the average electric field intensity within the relevant region of interest(ROI)was extracted.Then,we defined 34 critical nodes within DMN,CEN,SN,Subcortical Network,and Primary Sensory Network as ROI based on previous studies,and then calculated the functional connectivity between these ROI.Two-factor withinsubjects design repeated ANOVA was used for statistical purposes and further post-hoc was conducted based on significant interaction effects.Results showed that SMN-tDCS significantly induced alterations in functional connectivity patterns between/within the five core brain networks.Moreover,the change of functional connectivity also showed a significant negative correlation with the result of behavioral cognitive assessment and with the extracted mean electric field strength.In order to reveal the changes in connectivity between the three core cortical networks induced by SMN-tDCS,this study utilized the modulatory analysis model to explore the modulatory effects of stimulation target networks and subcortical network activities on the tri-core cortical networks.Based on the results of the significant interaction effects of the tri-core networks in the previous section,changes in the analysis of the moderation effects between/within the tri-core networks were further explored with Subcortical Network,and Primary Sensory Network as moderating variables.It was found that SMN-tDCS was modulated by stimulation target as well as the thalamus with significantly altered inter/intra modulation effects in the cortical triple core network.In conclusion,the study concluded that SMN-tDCS not only significantly affected the functional connectivity between/within its subcortical-cortical core brain network,but also that the altered connectivity was significantly correlated with motor imagery and fluid intelligence as well as with the intensity of cortical real stimulation.It was also possible to modulate the alteration of connectivity between distal networks(the three core cortical networks)through stimulation target as well as the thalamus,which provides a deeper understanding of the neuromodulatory mechanisms of tDCS intervention.