The Journal of Neuroscience, 2001, 21:RC196:1-4
RAPID COMMUNICATION
Rotational Remapping in Human Spatial Memory during Eye and
Head Motion
W. Pieter
Medendorp1, 2, 3,
Michael A.
Smith1, 2, 3,
Douglas B.
Tweed1, 2, 4, and
J. Douglas
Crawford1, 2, 3
1 Canadian Institutes of Health Research Group for
Action and Perception, 2 Centre for Vision Research, and
3 Department of Psychology, York University,
Toronto, Ontario, Canada M3J 1P3, and 4 Departments
of Physiology and Medicine, University of Toronto, Toronto, Ontario,
Canada M5S 1A8
The brain uses vision and other senses to compute the locations of
objects relative to the body, and then must update these locations when
the body moves. How geometrically sophisticated is this internal
updating? It has been suggested that updating simply shifts the stored
locations of all objects uniformly, by a common vector, when the eye or
head turns. For horizontal and vertical turns, a uniform shift would
often approximate the real changes in location of objects in front of
the subject. But for torsional rotations, a shift would be inadequate:
accurate updating would call for a more geometrically exact remapping,
not shifting but rotating the stored locations through the inverse of
the rotation of the eye in space. Here we asked human subjects to make
eye saccades to remembered targets after torsional head rotations. Their accuracy showed that spatial updating works in the torsional dimension and operates by rotation rather than shifting.
Key words:
remapping; coordinates; spatial perception; eye-head
movements; three-dimensional; human; spatial memory; rotation; rotational geometry
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