Institute of Science and Technology Austria, Am Campus 1, A-3400 Klosterneuburg, Austria.
Nat Commun. 2016 Jun 10;7:11824. doi: 10.1038/ncomms11824.
Hippocampal neurons encode a cognitive map of space. These maps are thought to be updated during learning and in response to changes in the environment through activity-dependent synaptic plasticity. Here we examine how changes in activity influence spatial coding in rats using halorhodopsin-mediated, spatially selective optogenetic silencing. Halorhoposin stimulation leads to light-induced suppression in many place cells and interneurons; some place cells increase their firing through disinhibition, whereas some show no effect. We find that place fields of the unaffected subpopulation remain stable. On the other hand, place fields of suppressed place cells were unstable, showing remapping across sessions before and after optogenetic inhibition. Disinhibited place cells had stable maps but sustained an elevated firing rate. These findings suggest that place representation in the hippocampus is constantly governed by activity-dependent processes, and that disinhibition may provide a mechanism for rate remapping.
海马体神经元对空间进行认知编码。这些地图被认为是在学习过程中以及通过活动依赖性突触可塑性对环境变化做出响应时进行更新的。在这里，我们使用介离子介导的、空间选择性的光遗传学沉默来研究活动变化如何影响大鼠的空间编码。盐藻视紫红质刺激会导致许多位置细胞和中间神经元的光诱导抑制；一些位置细胞通过去抑制而增加其放电，而有些则没有影响。我们发现，未受影响的亚群的位置场保持稳定。另一方面，受抑制的位置细胞的位置场不稳定，在光遗传学抑制前后的会话中出现重映射。去抑制的位置细胞具有稳定的地图，但持续维持升高的放电率。这些发现表明，海马体中的位置表示受活动依赖性过程的持续控制，而去抑制可能为速率重映射提供了一种机制。
