Vallortigara Giorgio, Pagni Piero, Sovrano Valeria Anna
University of Trieste, Trieste, Italy.
J Cogn Neurosci. 2004 Apr;16(3):390-400. doi: 10.1162/089892904322926737.
Research has proved that disoriented children and nonhuman animals can reorient themselves using geometric and nongeometric features of the environment, showing conjoined use of both types of information to different degree depending on species and developmental level. Little is known of the neurobiological bases of these spatial reorientation processes. Here we take advantage of the neuroanatomical peculiarities of the visual system of birds (showing segregation of information between the two sides of the brain to a considerable degree) to investigate the way in which geometric and nongeometric information is encoded and used by the left and right hemispheres. Domestic chicks were trained binocularly in an environment with a distinctive geometry (a rectangular cage) with panels at the corners providing nongeometric cues. Between trials, chicks were passively disoriented to disable dead reckoning. When tested after removal of the panels, left-eyed chicks, but not right-eyed chicks, reoriented using the residual information provided by the geometry of the cage. When tested after removal of geometric information (i.e., in a square-shaped cage), both right- and left-eyed chicks reoriented using the residual nongeometric information provided by the panels. When trained binocularly with only geometric information, at test, left-eyed chicks reoriented better than right-eyed chicks. Finally, when geometric and nongeometric cues provided contradictory information, left-eyed chicks showed more reliance on geometric cues, whereas right-eyed chicks showed more reliance on nongeometric cues. The results suggest separate mechanisms for dealing with spatial reorientation problems, with the right hemisphere taking charge of large-scale geometry of the environment and with both hemispheres taking charge of local, nongeometric cues when available in isolation, but with a predominance of the left hemisphere when competition between geometric and non-geometric information occurs.
研究已经证明，迷失方向的儿童和非人类动物可以利用环境的几何和非几何特征重新定位自己，根据物种和发育水平不同程度地联合使用这两种信息。对于这些空间重新定位过程的神经生物学基础知之甚少。在这里，我们利用鸟类视觉系统的神经解剖学特性（大脑两侧的信息在很大程度上是分离的）来研究左右半球对几何和非几何信息的编码和使用方式。将家鸡在一个具有独特几何形状（矩形笼子）的环境中进行双眼训练，笼子的角落有面板提供非几何线索。在试验之间，让小鸡被动迷失方向以禁用航位推算。当移除面板后进行测试时，左眼的小鸡，但不是右眼的小鸡，利用笼子的几何形状提供的剩余信息重新定位。当移除几何信息后进行测试时（即在正方形笼子中），右眼和左眼的小鸡都利用面板提供的剩余非几何信息重新定位。当仅用几何信息进行双眼训练时，在测试中，左眼的小鸡比右眼的小鸡重新定位得更好。最后，当几何和非几何线索提供相互矛盾的信息时，左眼的小鸡表现出更多地依赖几何线索，而右眼的小鸡表现出更多地依赖非几何线索。结果表明，处理空间重新定位问题有不同的机制，右半球负责环境的大规模几何形状，当非几何线索单独可用时，两个半球都负责局部非几何线索，但当几何和非几何信息之间发生竞争时，左半球占主导地位。
