Mirrored feedback in chronic stroke: recruitment and effective connectivity of ipsilesional sensorimotor networks.
BACKGROUND
Mirrored feedback has potential as a therapeutic intervention to restore hand function after stroke. However, the functional (effective) connectivity of neural networks involved in processing mirrored feedback after stroke is not known.


OBJECTIVE
To determine if regions recruited by mirrored feedback topographically overlap with those involved in control of the paretic hand and to identify the effective connectivity of activated nodes within the mirrored feedback network.


METHODS
Fifteen patients with chronic stroke performed a finger flexion task with their unaffected hand during event-related functional magnetic resonance imaging (fMRI). Real-time hand kinematics was recorded during fMRI and used to actuate hand models presented in virtual reality (VR). Visual feedback of the unaffected hand motion was manipulated pseudorandomly by either actuating the VR hand corresponding to the moving unaffected side (veridical feedback) or the affected side (mirrored feedback). In 2 control conditions, the VR hands were replaced with moving nonanthropomorphic shapes.


RESULTS
Mirrored feedback was associated with significant activation of regions within and outside the ipsilesional sensorimotor cortex, overlapping with areas engaged when patients performed the task with their affected hand. Effective connectivity analysis showed a significantly interconnected ipsilesional somatosensory and motor cortex in the mirrored feedback condition.


CONCLUSIONS
Mirrored feedback recruits ipsilesional brain areas relevant for control of the affected hand. These data provide a neurophysiological basis by which mirrored feedback may be beneficial as a therapy for restoring function after stroke.
['Saleh|Soha|S|', 'Adamovich|Sergei V|SV|', 'Tunik|Eugene|E|']
D000328:Adult D001696:Biomechanical Phenomena D001921:Brain D001931:Brain Mapping D002908:Chronic Disease D056228:Feedback, Sensory D005260:Female D007839:Functional Laterality D006225:Hand D006801:Humans D007909:Lenses D008279:Magnetic Resonance Imaging D008297:Male D008875:Middle Aged D009039:Motion Perception D009044:Motor Cortex D011601:Psychophysics D066191:Sensorimotor Cortex D020521:Stroke D014584:User-Computer Interface
mirrored feedback fMRI virtual reality motor control visuomotor integration