TY  - JOUR
A1  - Mehnert, Jan
A1  - Brunetti, Maddalena
A1  - Steinbrink, Jens
A1  - Niedeggen, Michael
A1  - Dohle, Christian
T1  - Effect of a mirror-like illusion on activation in the precuneus assessed with functional near-infrared spectroscopy
JF  - Journal of biomedical optics
N2  - Mirror therapy is a therapy to treat patients with pain syndromes or hemiparesis after stroke. However, the underlying neurophysiologic mechanisms are not clearly understood. In order to determine the effect of a mirror-like illusion (MIR) on brain activity using functional near-infrared spectroscopy, 20 healthy right-handed subjects were examined. A MIR was induced by a digital horizontal inversion of the subjects' filmed hand. Optodes were placed on the primary motor cortex (M1) and the occipito-parietal cortex (precuneus, PC). Regions of interest (ROI) were defined a priori based on previous results of similar studies and confirmed by the analysis of effect sizes. Analysis of variance of the ROI signal revealed a dissociated pattern: at the PC, the MIR caused a significant inversion of a hemispheric lateralization opposite to the perceived hand, independent of the moving hand. In contrast, activity in M1 showed lateralization opposite to the moving hand, but revealed no mirror effect. These findings extend our understanding on interhemispheric rivalry and indicate that a MIR is integrated into visuomotor coordination similar to normal view, irrespective of the hand that is actually performing the task. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)
KW  - functional near-infrared spectroscopy
KW  - optical imaging
KW  - mirror illusion
KW  - mirror therapy
KW  - precuneus
Y1  - 2013
U6  - https://doi.org/10.1117/1.JBO.18.6.066001
SN  - 1083-3668
VL  - 18
IS  - 6
PB  - SPIE
CY  - Bellingham
ER  - 
TY  - JOUR
A1  - Wang, Jing
A1  - Fritzsch, Claire
A1  - Bernarding, Johannes
A1  - Krause, Thomas
A1  - Mauritz, Karl-Heinz
A1  - Brunetti, Maddalena
A1  - Dohle, Christian
T1  - Cerebral activation evoked by the mirror illusion of the hand in stroke patients compared to normal subjects
JF  - Neurorehabilitation : an interdisciplinary journal
N2  - BACKGROUND: Mirror therapy (MT) was found to improve motor function after stroke, but its neural mechanisms remain unclear, especially in single stroke patients.
 OBJECTIVES: The following imaging study was designed to compare brain activation patterns evoked by the mirror illusion in single stroke patients with normal subjects.
 METHODS: Fifteen normal volunteers and five stroke patients with severe arm paresis were recruited. Cerebral activations during movement mirroring by means of a video chain were recorded with functional magnetic resonance imaging (fMRI). Single-subject analysis was performed using SPM 8.
 RESULTS: For normal subjects, ten and thirteen subjects displayed lateralized cerebral activations evoked by the mirror illusion while moving their right and left hand respectively. The magnitude of this effect in the precuneus contralateral to the seen hand was not dependent on movement speed or subjective experience. Negative correlation of activation strength with age was found for the right hand only. The activation pattern in stroke patients is comparable to that of normal subjects and present in four out of five patients.
 CONCLUSIONS: In summary, the mirror illusion can elicit cerebral activation contralateral to the perceived hand in the majority of single normal subjects, but not in all of them. This is similar even in stroke patients with severe hemiparesis.
KW  - Movement
KW  - mirror illusion
KW  - imaging
KW  - mirror therapy
KW  - stroke
Y1  - 2013
U6  - https://doi.org/10.3233/NRE-130999
SN  - 1053-8135
SN  - 1878-6448
VL  - 33
IS  - 4
SP  - 593
EP  - 603
PB  - IOS Press
CY  - Amsterdam
ER  -