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Abstract:
Covert attentional orienting was tested in a subject (AI) who
is unable to move her eyes due to a congenital extraocular muscle
fibrosis. It has been suggested that covert attention shifts result
from programmed but unexecuted eye movements. In addition, the
neural circuits of the eye movement system and the spatial
attention system have been intimately linked. Subject AI was tested
on a spatial attention task employing valid, invalid, and double
cues to assess covert orienting. Attentional orienting benefits
were obtained for a subject who cannot move, and has never moved,
her eyes. Thus, the shifting of covert attention is not dependent
on the ability to move the eyes. These data do not speak to a
possible independence of the neural circuits of the eye movement
system and the attention shifting system, as there are no neural
deficits in AI. However the results do suggest that the ability to
covertly shift spatial attention is independent of the ability to
execute an eye movement and of the experience of moving the
eyes.
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