Taube J S, Muller R U, Ranck J B
Department of Physiology, SUNY Health Sciences Center, Brooklyn 11203.
J Neurosci. 1990 Feb;10(2):436-47. doi: 10.1523/JNEUROSCI.10-02-00436.1990.
The discharge characteristics of postsubicular head-direction cells in a fixed environment were described in the previous paper (Taube et al., 1990). This paper reports changes in the firing properties of head-direction cells following changes in the animal's environment. Head-direction cells were recorded from rats as they moved freely in a 76-cm-diameter gray cylinder. A white card, occupying 100 degrees of arc, was taped to the inside wall of the cylinder and served as the major orienting spatial cue in the animal's environment. Rotation of the cue card produced near-equal rotation in the preferred firing direction of head-direction cells, with minimal changes in peak firing rate, directional firing range, or asymmetry of the firing-rate/head-direction function. Card removal had no effect on peak firing rate or range of firing, but in 8/13 cells the preferred direction rotated by at least 24 degrees. Similarly, changing the shape of the environment to a rectangular or square enclosure caused the preferred firing direction to rotate by at least 48 degrees for 8/10 cells in the rectangle and 3/8 cells in the square, with minimal changes in the peak firing rate or directional firing range. Hand holding the animals and moving them around the cylinder had no effect on the preferred direction or firing range of the cell, but decreased the maximal firing rate in 7/9 cells. On 2 occasions, 2 head-direction cells were recorded simultaneously. The rotation of the preferred firing direction for one cell was the same as the rotation of the preferred direction for the second cell after each environmental manipulation. These results demonstrate that specific visual cues in the environment can exert control over the preferred firing direction and indicate that head-direction cell firing is not a simple sensory response to visual cues, but rather represents more abstract information concerning the animal's spatial relationship with its environment. The constancy of the angle between the preferred firing directions of pairs of simultaneously recorded head-direction cells suggests that there is a fixed mapping of the population onto direction within the environment. Thus, environmental manipulations appear to cause only a change in the reference direction, but leave all other discharge characteristics of directional cells unchanged. In the discussion, comparisons are drawn between the responses of head-direction cells and hippocampal place cells to similar environmental manipulations (Muller and Kubie, 1987), and ways in which these 2 spatial systems interact in navigation are discussed.(ABSTRACT TRUNCATED AT 400 WORDS)
前一篇论文（陶布等人，1990年）描述了在固定环境中后下托头部方向细胞的放电特性。本文报告了动物环境变化后头部方向细胞放电特性的变化。当大鼠在直径76厘米的灰色圆柱体中自由移动时，记录其头部方向细胞。一张占据100度弧的白色卡片贴在圆柱体内壁上，作为动物环境中的主要定向空间线索。线索卡片的旋转使头部方向细胞的首选放电方向产生近乎相等的旋转，而峰值放电率、定向放电范围或放电率/头部方向函数的不对称性变化最小。移除卡片对峰值放电率或放电范围没有影响，但在13个细胞中有8个细胞的首选方向旋转了至少24度。同样，将环境形状改变为矩形或正方形围栏，导致矩形中10个细胞中的8个和正方形中8个细胞中的3个细胞的首选放电方向旋转至少48度，而峰值放电率或定向放电范围变化最小。手持动物并在圆柱体周围移动对细胞的首选方向或放电范围没有影响，但在9个细胞中有7个细胞的最大放电率降低。有两次，同时记录了两个头部方向细胞。每次环境操作后，一个细胞的首选放电方向的旋转与第二个细胞的首选方向的旋转相同。这些结果表明，环境中的特定视觉线索可以控制首选放电方向，并表明头部方向细胞放电不是对视觉线索的简单感觉反应，而是代表了关于动物与其环境空间关系的更抽象信息。同时记录的成对头部方向细胞的首选放电方向之间角度的恒定性表明，在环境中存在群体到方向的固定映射。因此，环境操作似乎只导致参考方向的改变，但方向细胞的所有其他放电特性保持不变。在讨论中，对头部方向细胞和海马位置细胞对类似环境操作的反应进行了比较（穆勒和库比，1987年），并讨论了这两个空间系统在导航中相互作用的方式。（摘要截断于400字）
