The Journal of Neuroscience, April 15, 2003, 23(8):3478
Rapid Spatial Reorientation and Head Direction Cells
Michaël B.
Zugaro,
Angelo
Arleo,
Alain
Berthoz, and
Sidney I.
Wiener
Centre National de la Recherche Scientifique-Collège de
France, Laboratoire de Physiologie de la Perception et de l'Action,
75231 Paris Cedex 05, France
It is surprising how quickly we can find our bearings when suddenly
confronted with a familiar environment, for instance when the lights
are turned on in a dark room. Subjectively, this appears to occur
almost instantaneously, yet the neural processes permitting this rapid
reorientation are unknown. A likely candidate is the head direction
(HD) cell system. These limbic neurons found in several brain regions,
including the thalamus and the hippocampus, discharge selectively when
the head of an animal is oriented in a particular ("preferred")
direction. This neuronal activity is independent of position and
ongoing behavior and is thus likely to constitute a physiological basis
for the sense of direction. Remarkably, although the HD cell system has
properties resembling those of a compass, it is independent of
geomagnetic fields. Rather, the preferred directions of the HD cells
are strongly anchored to visual cues in the environment. Here, we bring
evidence for the first time that a fundamental component of the
capacity to rapidly reorient in a familiar environment may be brought
about by updating of HD cell responses as rapidly as 80 msec after
changes in the visual scene. Continuous attractor networks have been
used successfully to model HD cell ensemble dynamics. The present
results suggest that after large rotations of the surrounding
landmarks, activity in such networks may be propagated in abrupt jumps
rather than in a gradually progressive manner.
Key words:
anterodorsal thalamic nucleus; update latency; spatial memory; landmark; visual orientation; attractor network
Copyright © 2003 Society for Neuroscience 0270-6474/03/2383478-05$05.00/0
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