A Study Of Cortical Functional Changes In Potential Myofascial Trigger Points Subjects Based On Functional Near-Infrared Spectroscopy

ObjectiveFunctional near-infrared spectroscopy(fNIRS)was used to study the effects of activating potential myofascial trigger points(MTrPs)on cortical activation and effective connectivity(EC)in subjects.MethodsIn this study,the cerebral oxygenation signals(oxygenated hemoglobin,deoxyhemoglobin and total hemoglobin)of left prefrontal cortex/right prefrontal cortex(LPFC/RPFC),left motor cortex/right motor cortex(LMC/RMC)and left occipital lobe/right occipital lobe(LOL/ROL)of subjects were measured by fNIRS in(1)resting-state,(2)non-MTrP-a and(3)MTrP-a.The WA and EC were used to describe the changes of cortical activation and brain network connectivity in the frequency bands associated with MTrPs.The Visual Analogue Scale(VAS)was used to assess the maximum pain that the subjects could tolerate while pressing,and the Kolmogorov-Smirnov and Levene tests were applied to test the variance normality and homogeneity of the data at the group level.Significant differences for the WA and EC between resting-state and MTrP-a,resting-state and non-MTrP-a,MTrP-a and non-MTrP-a were evaluated by one-way ANOVA.ResultsIn the frequency bands Ⅲ,Ⅳ and Ⅴ,WA,which represents the degree of cerebral cortex activation,increased between right trigger point(MTrP-a)and resting state,left nonMTrP-a and right trigger point(MTrP-a),left non-MTrP-a and resting state.And pressing the right trigger point(MTrP-a)when compared with the resting state,LPFC,RPFC,LMC,RMC part of the channel in the Ⅲ,Ⅳ frequency band,Some channels of RMC are activated significantly in the Ⅴ frequency band.Pressing the left non-trigger point when compared with pressing the right trigger point,LPFC and some channels of RPFC were significantly activated at frequencies Ⅲ and Ⅳ.Compared with the right trigger point(MTrP-a)and the resting state,the left non-MTrP-a and the right trigger point(MTrP-a),and the right trigger point(MTrP-a)and the resting state,the strength of the effect connection showed a decreasing trend in the frequency bands Ⅲ,Ⅳ and Ⅴ.And pressing the right trigger point(MTrP-a)when compared with the resting state:LMC→RMC,LOL→ROL,LPFC→ROL,RMC→LMC in the Ⅳ and Ⅴ bands effect connection strength decreased significantly.Compared with pressing the left non-MTrP-a,the effect connection strength of LOL→ROL in the Ⅳ band was significantly decreased.Comparison of mCD in the resting state,the left non-MTrP-a and the right trigger point(MTrP-a),most of the direction of connection between cerebral cortex regions changed from the connection with the main coupling direction to the bidirectional connection without the main coupling direction.Conclusions1.Press MTrP-a and the non-MTrP-a,cerebral cortex may by vascular muscle source,neurogenic and endothelial cell metabolism and other factors,lead to nerve vascular coupling function obstacle and lead to neuronal activity,different channels and brain interval brain network connection strength and the direction of change in multiple frequency bands.2.Pressing one myofascial trigger point can cause activation of the cerebral cortex on both sides,which generally weakens the strength of the effective connection between the cerebral cortex regions and changes the direction of connection from the main coupling direction to the bidirectional direction.It may be one of the central sensitization mechanisms.