Lipton Paul A, White John A, Eichenbaum Howard
Department of Psychology, Boston University, Boston, Massachusetts 02215, USA.
J Neurosci. 2007 May 23;27(21):5787-95. doi: 10.1523/JNEUROSCI.1063-07.2007.
Hippocampal neuronal activity distinguishes separate events that share common elements. Here, we examined whether the capacity to disambiguate overlapping experiences is an exclusive feature of hippocampal processing or whether information processing one stage earlier in the hippocampal system also disambiguates common elements of distinct experiences. We compared the spatial firing patterns of neurons in the dorsocaudal medial entorhinal cortex (dcMEC) and hippocampal CA1 neurons in animals continuously alternating left-turn and right-turn routes through a T-maze. Neurons in the dcMEC more strongly distinguished left-turn from right-turn trials compared with CA1 neurons, whereas CA1 neurons more selectivity encoded places traversed within each route. These results indicate that dcMEC spatial firing patterns are experience dependent and reflect the mnemonic demands of a spatial memory task. Furthermore, the results suggest that neuronal populations in the dcMEC and CA1 differentially emphasize complementary aspects of spatial memory representations.
海马体神经元活动能够区分具有共同元素的不同事件。在此，我们研究了区分重叠经历的能力是海马体处理过程的独有特征，还是海马体系统中更早阶段的信息处理也能区分不同经历的共同元素。我们比较了动物在T型迷宫中连续交替进行左转和右转路线时，背尾侧内侧内嗅皮层（dcMEC）神经元和海马体CA1神经元的空间放电模式。与CA1神经元相比，dcMEC中的神经元在区分左转和右转试验方面表现得更为明显，而CA1神经元则更具选择性地编码每条路线内经过的位置。这些结果表明，dcMEC的空间放电模式依赖于经历，并反映了空间记忆任务的记忆需求。此外，结果还表明，dcMEC和CA1中的神经元群体在空间记忆表征的互补方面存在差异。
