Selective, non-lateralized impairment of motor imagery following right parietal damage.
Using variants of a visually guided pointing task, in which subjects make pointing movements towards targets of varying sizes, we explored motor imagery in a patient with visual neglect. When this patient actually pointed towards targets of different sizes he showed the normal correlation between movement duration (MD) and target size, such that MD increased as target size decreased. In contrast, his imagined movements did not show the same speed-accuracy trade-off observed for actual movements. This was true regardless of the hand used or the initial direction of movement (left versus right). The patient performed normally on several tasks of visual imagery, including size estimation, perceptual discrimination and localization of cities on an imagined map. This patient's performance suggests that the networks in the right parietal lobe play an important role in the generation of internal models of motor movements regardless of the hand used to perform the task.
Danckert
James
J
CIHR Group on Action and Perception, Department of Psychology, University of Western Ontario, Social Sciences Centre, London, Ontario, Canada. jdancker@uwo.ca
Ferber
Susanne
S
Doherty
Timothy
T
Steinmetz
Helena
H
Nicolle
David
D
Goodale
Melvyn A
MA
D000368:Aged; D003072:Cognition Disorders / Q000523:psychology*; D005246:Feedback / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006225:Hand / Q000502:physiology; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D010296:Parietal Lobe / Q000473:pathology*; D011597:Psychomotor Performance; D020521:Stroke / Q000473:pathology / Q000523:psychology