Authors: Osnat Yaski David Eilam
Publish Date: 2007/02/22
Volume: 10, Issue: 4, Pages: 415-428
Abstract
This study was aimed at uncovering physical and geometric properties that make a particular landmark a target of exploration and navigation Rats were tested in a square openfield arena with additional portable corners featuring the same properties as the arena corners It was found that the routes of progression converged upon the added corners whether located at the arena wall or the arena center Route convergence upon the added corners involved numerous visits to these corners However time spent at the added corners was relatively short compared with the arena corners including that from which rats were introduced into the arena There was no differential effect of testing rats in light or dark or with a low versus a high portable corner It is suggested that the added corners were distinct against the background of the arena enclosure whereas the four arena corners and walls were encoded by the rats as one geometric module This distinctness together with the greater accessibility of the added corners made them salient landmarks and a target of exploration Thus the impact of a landmark extended beyond its specific selfgeometry to include accessibility and distinctness which are contextual properties In addition to the contextual impact on locomotor behavior there was also a temporal effect with security initially dominating the rats’ behavior but then declining along with an increased attraction to salient landmarks These spatiotemporal patterns characterized behavior in both lit and dark arenas indicating that distal cues were secondary to local proximal cues in shaping routesWe are grateful to Tali Nitzan for help in the experiments Reut Avni for comments and Naomi Paz for editing the manuscript This research was supported by ‘The Israel Science Foundation’ Grant 471/04 This study was carried out under permit L05049 of the ‘TAU Institutional ethics committee for animal experimentation’
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