Imagine waking up to find that the left half of your world was missing.
Your everyday life would be devastated by no longer being able to notice
anything to the left - even food on the left of your plate. Even worse,
it would be like your very concept of left itself was impaired. Your
everyday perceptions of the world and your interactions in it would
suffer. This disorder, called hemispatial neglect, is a common result
of stroke that affects thousands of Canadians every year.
Damage to the right hemisphere often results in hemispatial neglect, a
failure to attend to or report information appearing on the left side
of space despite intact sensory processing and visual acuity. Neglect
can be debilitating in everyday life; patients may fail to notice
objects on the left of a scene, may ignore words on the left of a
page, and typically, omit to copy features on the left of a figure
while preserving the corresponding features on the right. While
previous research has suggested that patients with parietal lobe
neglect have a deficit that is mainly perceptual in nature, Dr.
Marotta's recent work has revealed that hemispatial neglect also
impairs the programming and control of visually guided grasping -
possibly by preventing the formation of a complete representation
of an object.
Dr. Marotta's research in this area is aimed at providing a better
understanding of the neurological basis of hemispatial neglect and
its effects on perception and action. Insight from this research
will help in the development of sophisticated diagnostic tools and
more theoretically-motivated approaches to the rehabilitation of
patients with this common disorder. In addition, this work also
provides a crucial bridge to the important analogous lesion and
single-unit studies in nonhuman primates that record parietal activity
during eye-hand coordination.
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Feloiu, F.D., Marotta, J.J., Vesia, M., Black, S.E. & Crawford, J.D. (2008).
Left-to-right reversal of hemispatial neglect symptoms following adaptation to reversing prisms.
In M. Jenkin and L.R. Harris (Eds), Cortical Mechanisms of Vision (pp. 138-155). New York, NY: Cambridge University Press.
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Feloiu F.D., Marotta, J.J., Black, S.E. & Crawford, J.D. (2005).
Adaptation to reversing prisms: pointing in patients with right-parietal damage.
Vision Sciences Society, Journal of Vision, 5(8), 120a.
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Marotta, J.J., McKeeff, T.J. & Behrmann, M. (2003).
Hemispatial neglect: its effects on visual perception and visually guided grasping.
Neuropsychologia, 41(9), 1262-1271.
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