Abstract：
Hippocampus is essential for episodic memory formation, lesion studies demonstrating its role especially in processing spatial and temporal information. Further, adult hippocampal neurogenesis (AHN) in the dentate gyrus (DG) has also been linked to learning. To study hippocampal neuronal activity during events like learning, in vivo calcium imaging has become increasingly popular. It relies on the use of adeno-associated viral (AAV) vectors, which seem to lead to a decrease in AHN when applied on the DG. More notably, imaging requires the implantation of a relatively large lens into the tissue. Here, we examined how injection of an AAV vector and implantation of a 1-mm-diameter lens into the dorsal DG routinely used to image calcium activity impact the behavior of adult male C57BL/6 mice. To this aim, we conducted open-field, object-recognition and object-location tasks at baseline, after AAV vector injection, and after lens implantation. Finally, we determined AHN from hippocampal slices using a doublecortin-antibody. According to our results, the operations needed for in vivo imaging of the dorsal DG did not have adverse effects on behavior, although we noticed a decrease in AHN ipsilaterally to the operations. Thus, our results suggest that in vivo imaging can be safely used to, for example, correlate patterns of calcium activity with learned behavior. One should still keep in mind that the defects on the operated side might be functionally compensated by the (hippocampus in the) contralateral hemisphere.
摘要：
海马对于情景记忆的形成至关重要，病变研究表明其作用，特别是在处理空间和时间信息。Further,齿状回（DG）中的成年海马神经发生（AHN）也与学习有关。为了研究学习等事件期间的海马神经元活动，体内钙成像越来越普及。它依赖于腺相关病毒（AAV）载体的使用，当应用于DG时，这似乎导致AHN降低。更值得注意的是,成像需要将相对较大的晶状体植入组织中。这里,我们研究了常规用于钙活动成像的AAV载体的注射和直径1毫米的晶状体植入背侧DG对成年雄性C57BL/6小鼠的行为的影响.为了这个目标,我们进行了开场，基线处的对象识别和对象定位任务，AAV载体注射后，和晶状体植入后。最后,我们使用双抗体从海马切片中确定了AHN。根据我们的结果,背侧DG体内成像所需的操作对行为没有不利影响，尽管我们注意到AHN在同上减少了。因此，我们的结果表明，体内成像可以安全地用于，例如,钙活动模式与学习行为相关。仍然应该记住，手术侧的缺陷可能会在功能上由对侧半球（海马体）补偿。
