Recently, we argued that the neurocognitive mechanisms involved in the emergence of the vivid (non-veridical) experience of willed actions may depend on continued functioning of the intention-programming system (Berti et al, 2007). We predicted that during bimanual motor acts, anosognosic patients will show an influence of intended (but unexecutable) contralesional hand movement on the actual movements of the intact ipsilesional hand (bimanual coupling effect).Participants (4 hemiplegic patients, 1 with and 3 without anosognosia, plus 12 age-matched healthy controls) were asked to perform Bimanual congruent (both hands should move along a vertical line) and Bimanual non-congruent (right hand executed a vertical line, left hand a circle) movements in two conditions: a Real condition in which the subject was asked to actually move the left hand and an Imagery condition in which the subject was asked to imagine move the left hand (cf. Franz and Ramachandran, 1998). Right hand movements were registered with a tablet PC. Any bimanual coupling effects were calculated as the standard deviation (mm) from the trajectory of a strictly vertical path. In accord with our prediction, in the Real non-congruent condition we observed a coupling effect in the anosognosic patient as well as the healthy controls, whereas we did not observe any significative coupling effects in hemiplegic patients without anosognosia. We also did not observed coupling effects in healthy controls and in the anosognosic patient (as well as in hemiplegic patients without anosognosia) in the Imagery noncongruent condition. Thus, the intention to move one hand, even if this hand is not moving at all, could lead to a vivid awareness of the movement itself and this experience can go as far as to influence motor parameters of the other hand.
The effect of intention to move on motor execution: the case of anosognosia for hemiplegia
GARBARINI, FRANCESCA;PIEDIMONTE, ALESSANDRO;PIA, Lorenzo;BERTI, Annamaria
2010-01-01
Abstract
Recently, we argued that the neurocognitive mechanisms involved in the emergence of the vivid (non-veridical) experience of willed actions may depend on continued functioning of the intention-programming system (Berti et al, 2007). We predicted that during bimanual motor acts, anosognosic patients will show an influence of intended (but unexecutable) contralesional hand movement on the actual movements of the intact ipsilesional hand (bimanual coupling effect).Participants (4 hemiplegic patients, 1 with and 3 without anosognosia, plus 12 age-matched healthy controls) were asked to perform Bimanual congruent (both hands should move along a vertical line) and Bimanual non-congruent (right hand executed a vertical line, left hand a circle) movements in two conditions: a Real condition in which the subject was asked to actually move the left hand and an Imagery condition in which the subject was asked to imagine move the left hand (cf. Franz and Ramachandran, 1998). Right hand movements were registered with a tablet PC. Any bimanual coupling effects were calculated as the standard deviation (mm) from the trajectory of a strictly vertical path. In accord with our prediction, in the Real non-congruent condition we observed a coupling effect in the anosognosic patient as well as the healthy controls, whereas we did not observe any significative coupling effects in hemiplegic patients without anosognosia. We also did not observed coupling effects in healthy controls and in the anosognosic patient (as well as in hemiplegic patients without anosognosia) in the Imagery noncongruent condition. Thus, the intention to move one hand, even if this hand is not moving at all, could lead to a vivid awareness of the movement itself and this experience can go as far as to influence motor parameters of the other hand.
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