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Abstract:
Abstract: Anosognosia refers to a lack of awareness or
explicit denial of neurologic deficit. We report a patient (CW)
with bilateral posterior parietal lesions (Left >Right) who
exhibited a mild right hemiparesis and performed poorly on a series
of tasks assessing the integrity of putative body representations
including the body "structural description", "body schema" and
"body image". Of greatest relevance here, CW exhibited anosognosia
for movement of both hands. When asked to imagine movements of the
fingers of his hands with his eyes closed, he produced the
"imagined" movements but denied doing so. Additionally, when asked
to produce the same movements with his eyes closed, his movements
were both slower and significantly less precise as judged by
spatial accuracy measures and the evaluation by blinded judges of
videotaped movements of his hands. Functional magnetic resonance
imaging (fMRI) techniques were used to examine activity associated
with imagined and executed finger movements. Results will be
discussed in terms of: (1) inhibitory deficits following brain
damage, (2) the role of the posterior parietal cortex in
monitoring/updating the spatial relations between body parts, and
(3) the possibility that motor imagery and motor execution may rely
on activity in partially segregated neuronal populations.
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