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Abstract:
Abstract: Previous behavioral and neurophysiological studies
suggest the brain constructs multiple representations of space. How
these representations are bound to give humans a coherent sense of
space is not clear. We investigated binding between personal and
peripersonal space using tactile extinction. We hypothesized that
mechanisms which access peripersonal space would improve deficits
of personal spatial awareness if they bind personal and
peripersonal representations. Visual-tactile and tactile-motor
integration were considered as two candidate mechanisms. Ten right
hemisphere stroke patients were touched with probes under
contrasting conditions: looking at their left versus right hands,
and receiving the stimuli passively versus moving their fingers
actively on the probes. The patients were more aware of tactile
stimuli when looking at their left hand than when looking at their
right hand (51.4% accurate looking left, 22.8% looking right,
p<0.0001 with bilateral stimulation and 88.6% looking left,
67.6% looking right, p<0.0001 with unilateral left stimulation).
Five patients not paralyzed on the left were also more aware of
tactile stimuli when they actively moved on the probe than when
they passively received the stimuli (57.6% accurate with movement,
23.2% without, p<0.0001). Cross-modal and sensori-motor
integration increased awareness of contralesional spatial
locations, suggesting these mechanisms bind personal and
peripersonal space.
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