Effective Connectivity of Cortical Sensorimotor Networks During Finger Movement Tasks: A Simultaneous fNIRS, fMRI, EEG Study

Abstract

Recently, interest has been growing to understand the underlying dynamic directional relationship between simultaneously activated regions of the brain during motor task performance. Such directionality analysis (or effective connectivity analysis), based on non-invasive electrophysiological (electroencephalography-EEG) and hemodynamic (functional near infrared spectroscopy-fNIRS; and functional magnetic resonance imaging-fMRI) neuroimaging modalities can provide an estimate of the motor task-related information flow from one brain region to another. Since EEG, fNIRS and fMRI modalities achieve different spatial and temporal resolutions of motor-task related activation in the brain, the aim of this study was to determine the effective connectivity of cortico-cortical sensorimotor networks during finger movement tasks measured by each neuroimaging modality. Nine healthy subjects performed right hand finger movement tasks of different complexity (simple finger tapping-FT, simple finger sequence-SFS, and complex finger sequence-CFS). We focused our observations on three cortical regions of interest (ROIs), namely the contralateral sensorimotor cortex (SMC), the contralateral premotor cortex (PMC) and the contralateral dorsolateral prefrontal cortex (DLPFC). We estimated the effective connectivity between these ROIs using conditional Granger causality (GC) analysis determined from the time series signals measured by fMRI (blood oxygenation level-dependent-BOLD), fNIRS (oxygenated-O2Hb and deoxygenated-HHb hemoglobin), and EEG (scalp and source level analysis) neuroimaging modalities. The effective connectivity analysis showed significant bi-directional information flow between the SMC, PMC, and DLPFC as determined by the EEG (scalp and source), fMRI (BOLD) and fNIRS (O2Hb and HHb) modalities for all three motor tasks. However the source level EEG GC values were significantly greater than the other modalities. In addition, only the source level EEG showed a significantly greater forward than backward information flow between the ROIs. This simultaneous fMRI, fNIRS and EEG study has shown through independent GC analysis of the respective time series that a bi-directional effective connectivity occurs within a cortico-cortical sensorimotor network (SMC, PMC and DLPFC) during finger movement tasks.

The Hemodynamic Mass Action of a Central Pattern Generator

“…Our findings are consistent with those obtained in the human brain with the simultaneous use of the fNIRS and the fMRI (for review see Steinbrink et al, 2006;Scarapicchia et al, 2017). There is compelling evidence that the changes in the BOLD fMRI signal are related to changes in deoxy-Hb, total-Hb, and regional cerebral blood volume during a variety of sensory, motor, cognitive tasks and resting states (Sakatani et al, 2007;Cui et al, 2011;Duan et al, 2012;Quaresima et al, 2012;Sasai et al, 2012;Tong et al, 2012;Sato et al, 2013;Yuan and Ye, 2013;Fabiani et al, 2014;Hocke et al, 2015;Noah et al, 2015;Anwar et al, 2016;Vannasing et al, 2016). Our findings are also supported by studies in mice with the simultaneous recording of fluorescentbased calcium recordings and BOLD fMRI signals (Schlegel et al, 2018).…”

Focal Hemodynamic Responses in the Stimulated Hemisphere During High-Definition Transcranial Direct Current Stimulation

“…Neuroimaging methods can be used to provide information about the brain-tissue effects of the tDCS electric fields when measured in a resting-state during (15)(16)(17)(18)(19)(20)(21)(22) and/or after (23-25) neurostimulation. Hemodynamic-based neuroimaging methods, such as positron emission tomography (PET), functional magnetic resonance imaging (fMRI), and functional near-infrared spectroscopy (fNIRS), detect cerebral hemodynamic changes based on neurovascular coupling mechanisms (26,27). Thus when a specific brain region is activated, regional cerebral blood flow (rCBF) increases in a temporally and spatially coordinated manner tightly linked to changes in neural activity through a complex sequence of coordinated events involving neurons, glia, arteries/arterioles, and signaling molecules (28,29).…”

Functional near‐infrared spectroscopy to probe sensorimotor region activation during electrical stimulation‐evoked movement

“…As a control condition, VOL wrist extension movements of the right arm also activated bilateral sensorimotor regions with significantly greater (~1·5x) contralateral LH than ipsilateral RH activation. These findings are consistent with a greater contralateral than ipsilateral sensorimotor region activation to perform unilateral VOL motor tasks assessed using fNIRS (Leff et al ., ) and fMRI neuroimaging (Ehrsson et al ., ; Muthalib et al ., ; Anwar et al ., ). Using TD‐fNIRS with NIRS‐SPM analysis (Muthalib et al ., ), only a significant contralateral LH activation pattern was found during VOL condition.…”