Grey-box modeling and hypothesis testing of functional near-infrared spectroscopy-based cerebrovascular reactivity to anodal high-definition tDCS in healthy humans

• DOI: 10.1371/journal.pcbi.1009386
• Publication Date: 2021-10-06T19:11:51Z
• Authors: Yashika Arora; Pushpinder Walia; Mitsuhiro Hayashibe; Makii Muthalib; Shubhajit Roy Cho...; Stephane Perrey; Anirban Dutta
• Keywords: Akaike information criterion; Transcranial Direct Current Stimulation

Transcranial direct current stimulation (tDCS) has been shown to evoke hemodynamics response; however, the mechanisms have not investigated systematically using systems biology approaches. Our study presents a grey-box linear model that was developed from physiologically detailed multi-compartmental neurovascular unit consisting of vascular smooth muscle, perivascular space, synaptic and astrocyte glial cell. Then, linearization performed on nonlinear find appropriate complexity (Akaike information criterion) fit functional near-infrared spectroscopy (fNIRS) based measure blood volume changes, called cerebrovascular reactivity (CVR), high-definition (HD) tDCS. The applied fNIRS-based CVR during first 150 seconds anodal HD-tDCS in eleven healthy humans. models for each four nested pathways starting tDCS scalp density perturbed potassium released active neurons Pathway 1, astrocytic transmembrane 2, concentration 3, voltage-gated ion channel muscle cell 4 were fitted total hemoglobin (tHb) changes optodes vicinity 4x1 electrodes as well contralateral sensorimotor cortex. We found perturbation 3 presented least mean square error (MSE, median <2.5%) lowest Akaike criterion (AIC, -1.726) individual fitting at targeted-region. minimal realization transfer function with reduced-order approximations ensemble average tHb time series. Again, nine poles two zeros (all free parameters), provided best Goodness Fit 0.0078 Chi-Square difference test pathways. Therefore, our approach investigate initial transient hemodynamic response fNIRS data. Future studies need steady-state responses, including oscillations be driven by calcium dynamics, where transcranial alternating may provide frequency-dependent physiological entrainment system identification. postulate such mechanistic understanding identification electrical can facilitate adequate delivery tissue under simultaneous portable imaging various diseases.