Bingman Verner P, Hough Gerald E, Kahn Meghan C, Siegel Jennifer J
Department of Psychology and J.P. Scott Center for Neuroscience, Mind and Behavior, Bowling Green State University, Bowling Green, OH 43403, USA.
Brain Behav Evol. 2003;62(2):117-27. doi: 10.1159/000072442.
The hippocampus (HF) of birds and mammals is essential for the map-like representation of environmental landmarks used for navigation. However, species with contrasting spatial behaviors and evolutionary histories are likely to display differences, or 'adaptive specializations', in HF organization reflective of those contrasts. In the search for HF specialization in homing pigeons, we are investigating the spatial response properties of isolated HF neurons and possible right-left HF differences in the representation of space. The most notable result from the recording work is that we have yet to find neurons in the homing pigeon HF that display spatial response properties similar to HF 'place cells' of rats. Of interest is the suggestion of neurons that show higher levels of activity when pigeons are near goal locations and neurons that show higher levels of activity when pigeons are in a holding area prior to be being placed in an experimental environment. In contrast to the rat, the homing pigeon HF appears to be functionally lateralized. Results from a current lesion study demonstrate that only the left HF is sensitive to landmarks that are located within the boundaries of an experimental environment, whereas the right HF is indifferent to such landmarks but sensitive to global environmental features (e.g., geometry) of the experimental space. The preliminary electrophysiological and lateralization results offer interesting departure points for better understanding possible HF specialization in homing pigeons. However, the pigeon and rat HF reside in different forebrain environments characterized by a wulst and neocortex, respectively. Differences in the forebrain organization of pigeons and rats, and birds and mammals in general, must be considered in making sense of possible species differences in how HF participates in the representation of space.
鸟类和哺乳动物的海马体（HF）对于用于导航的环境地标地图状表征至关重要。然而，具有不同空间行为和进化历史的物种可能在HF组织中表现出差异，即“适应性特化”，以反映这些差异。在寻找归巢鸽的HF特化过程中，我们正在研究孤立的HF神经元的空间反应特性以及HF在空间表征中可能存在的左右差异。记录工作最显著的结果是，我们尚未在归巢鸽的HF中发现具有与大鼠HF“位置细胞”相似空间反应特性的神经元。有趣的是，有迹象表明，当鸽子靠近目标位置时，某些神经元的活动水平较高；当鸽子在被放置于实验环境之前处于等待区域时，另一些神经元的活动水平较高。与大鼠不同，归巢鸽的HF似乎在功能上存在偏侧化。当前一项损伤研究的结果表明，只有左HF对位于实验环境边界内的地标敏感，而右HF对这类地标不敏感，但对实验空间的整体环境特征（如几何形状）敏感。初步的电生理和偏侧化结果为更好地理解归巢鸽可能存在的HF特化提供了有趣的切入点。然而，鸽子和大鼠的HF分别位于以厚皮质和新皮质为特征的不同前脑环境中。在理解HF参与空间表征的过程中，鸽子和大鼠以及鸟类和哺乳动物在前脑组织上的差异必须加以考虑。
