Network interactions underlying mirror feedback in stroke: A dynamic causal modeling study

Abstract

Mirror visual feedback (MVF) is potentially a powerful tool to facilitate recovery of disordered movement and stimulate activation of under-active brain areas due to stroke. The neural mechanisms underlying MVF have therefore been a focus of recent inquiry. Although it is known that sensorimotor areas can be activated via mirror feedback, the network interactions driving this effect remain unknown. The aim of the current study was to fill this gap by using dynamic causal modeling to test the interactions between regions in the frontal and parietal lobes that may be important for modulating the activation of the ipsilesional motor cortex during mirror visual feedback of unaffected hand movement in stroke patients. Our intent was to distinguish between two theoretical neural mechanisms that might mediate ipsilateral activation in response to mirror-feedback: transfer of information between bilateral motor cortices versus recruitment of regions comprising an action observation network which in turn modulate the motor cortex. In an event-related fMRI design, fourteen chronic stroke subjects performed goal-directed finger flexion movements with their unaffected hand while observing real-time visual feedback of the corresponding (veridical) or opposite (mirror) hand in virtual reality. Among 30 plausible network models that were tested, the winning model revealed significant mirror feedback-based modulation of the ipsilesional motor cortex arising from the contralesional parietal cortex, in a region along the rostral extent of the intraparietal sulcus. No winning model was identified for the veridical feedback condition. We discuss our findings in the context of supporting the latter hypothesis, that mirror feedback-based activation of motor cortex may be attributed to engagement of a contralateral (contralesional) action observation network. These findings may have important implications for identifying putative cortical areas, which may be targeted with non-invasive brain stimulation as a means of potentiating the effects of mirror training.

The Activation of the Mirror Neuron System during Action Observation and Action Execution with Mirror Visual Feedback in Stroke: A Systematic Review

“…Another study enrolled both patients who have had strokes and brain tumors, and the data of stroke participants could not be separated; these studies were hence excluded [ 16 , 44 ]. Finally, 19 articles satisfied our inclusion criteria and were included in the present review [ 13 , 22 , 28 , 34 , 45 – 59 ]. Figure 1 shows the identification process for the selection of studies.…”

“…Eight articles explored the concurrent effects of AO or action execution with MVF on brain activation, evidenced by fMRI [ 34 , 47 , 48 , 50 , 53 , 55 – 57 ]. In studies regarding MVF, Michielsen et al found that bimanual movement with MVF led to significant activation of the precuneus and the posterior cingulate cortex (PCC), rather than the MNS [ 53 ].…”

“…MVF could boost the effects of the conventional upper limb rehabilitation of stroke [ 33 ]. It has been proposed that the training-induced effects of MVF arise from the activation of the ipsilesional primary motor cortex by enriching the visual and proprioceptive inputs to the MNS [ 10 , 19 , 34 ], but this hypothesis has not been duly confirmed in human studies [ 35 ].…”

Virtual Reality Applications for Neurological Disease: A Review

“…Saleh et al, 2017 Single Intervention: A VR goal-directed finger flexion movement with their unaffected hand while observing real-time visual feedback of the corresponding (veridical) or opposite (mirror) hand.fMRIStanden et al, 2017 Eight Weeks Training: Randomly divided into 2 conditions: (1) VR employing infrared capture to translate the position of the hand into gameplay or usual care;(2) Control -usual care. (1) Wolf Motor Function Test;(2) Nine-Hole Peg Test;(3) Motor Activity Log; (4) Nottingham Extended Activities of Daily Living.…”

Effect of brain training through visual mirror feedback, action observation and motor imagery on orofacial sensorimotor variables: A single‐blind randomized controlled trial

“…VMF is a commonly employed regimen in rehabilitation wherein patients receive visual input of the movement while the movement is being executed . It has been proposed that the training‐inducing effects of VMF arise from enriching the visual and proprioceptive inputs to the MNS . MI is defined as the dynamic mental execution of an action, without its actual motor execution …”