Bostock E, Muller R U, Kubie J L
Department of Physiology, SUNY Health Sciences Center at Brooklyn 11203.
Hippocampus. 1991 Apr;1(2):193-205. doi: 10.1002/hipo.450010207.
Understanding the empirical rules that regulate alterations of hippocampal firing fields will enhance our understanding of hippocampal function. The current study sought to extend previous research in this area by examining the effect of substituting a new stimulus for a familiar stimulus in a familiar environment. Hippocampal place cells were recorded while rats chased food pellets scattered onto the floor of a cylindrical apparatus with a white cue card affixed to the apparatus wall. Once a place cell had been recorded in the presence of the white card, the white card was replaced by a black card of the same size and shape. The place cell was then recorded in the presence of the black card. Thirty-six cells were recorded using this procedure. All cells had stable firing fields in the presence of the white card. Both the white and black cards had stimulus control over place cell firing; generally, rotation of either card caused an equal rotation of the firing fields present. When the black card was substituted for the white card, place cells showed time-variant changes in their spatial firing patterns. The change was such that the spatial firing patterns of the majority of place cells were similar in the presence of the white and black cards during initial black card exposures. During subsequent presentations of the black card, the spatial firing patterns associated with the 2 cards became distinct from each other. Once the differentiation of firing patterns had occurred in a given rat, all place cells subsequently recorded from that rat had different firing patterns in the presence of the white and black cards. The findings are discussed relative to sensory-, motor-, attentional-, and learning-related interpretations of hippocampal function. It is argued that the time-variant alteration of place cell firing fields observed following exposure to a novel stimulus in this study reflects an experience-dependent modification of place cell firing patterns.
了解调节海马体放电场变化的经验法则将增进我们对海马体功能的理解。当前的研究试图通过在熟悉的环境中用新刺激替代熟悉刺激来扩展该领域之前的研究。在大鼠追逐散落在圆柱形装置地板上的食物颗粒时记录海马体位置细胞，该装置壁上贴有白色提示卡。一旦在白色卡片存在的情况下记录到一个位置细胞，就将白色卡片换成相同大小和形状的黑色卡片。然后在黑色卡片存在的情况下记录该位置细胞。使用此程序记录了36个细胞。在白色卡片存在的情况下，所有细胞都有稳定的放电场。白色和黑色卡片对位置细胞的放电都有刺激控制作用；一般来说，任一张卡片的旋转都会导致现有放电场发生同等程度的旋转。当用黑色卡片替代白色卡片时，位置细胞在其空间放电模式上表现出随时间变化的改变。这种变化使得在最初接触黑色卡片期间，大多数位置细胞在白色和黑色卡片存在时的空间放电模式相似。在随后展示黑色卡片时，与这两张卡片相关的空间放电模式变得彼此不同。一旦在给定的大鼠中发生了放电模式的分化，随后从该大鼠记录的所有位置细胞在白色和黑色卡片存在时都有不同的放电模式。我们将结合对海马体功能的感觉、运动、注意力和学习相关的解释来讨论这些发现。有人认为，在本研究中观察到的在接触新刺激后位置细胞放电场随时间变化的改变反映了位置细胞放电模式的经验依赖性改变。
