Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
Behav Brain Res. 2021 Aug 27;412:113414. doi: 10.1016/j.bbr.2021.113414. Epub 2021 Jun 10.
Working memory is a construct that contains goal maintenance, interference control and memory capacity domains. Spatial working memory in presence of conflicting stimuli requires segregation and maintenance of the relevant information about a goal over a short period of time. Besides the prefrontal cortex, the hippocampus is an anatomical substrate for the working memory. We hypothesized that in a highly challenging task, where spatial stimuli are in a conflict and only some of them describe the goal location, the spatial working memory will be strongly dependant on the hippocampus. To verify this, we used an allothetic place avoidance alternation task (APAAT). Performance of this task demands a small number of entries and a long maximum time avoided between consecutive entries to the shock sector. These parameters reflected both domains of working memory. The experiment was conducted on hippocampal lesioned (HIPP n = 12) and sham-operated (CTRL n = 8) rats trained in four APAAT days, each consisting of four 5-minute stages: habituation, stage1 (st1) and stage2 (st2) of memory training, a 5-minute break followed by a retrieval test. The position of the shock sector was changed each day. The HIPP rats were impaired on both stages of memory training, whereas CTRL rats presented significant memory improvement on stage2. In HIPP rats the cognitive skill learning measured as shock per entrance ratio was compromised. Hippocampal lesions did not impair locomotor activity. In summary, even slight bilateral damage to the hippocampus is blocking working memory formation in a difficult task.
工作记忆是一个包含目标维持、干扰控制和记忆容量等多个领域的概念。在存在冲突刺激的情况下，空间工作记忆需要在短时间内对目标的相关信息进行分离和维持。除了前额叶皮层外，海马体也是工作记忆的解剖学基础。我们假设，在一个极具挑战性的任务中，空间刺激存在冲突，只有其中一些能够描述目标位置，那么空间工作记忆将强烈依赖于海马体。为了验证这一点，我们使用了异体回避交替任务（APAAT）。完成这项任务需要少量的进入次数和在连续进入回避区域之间的最长回避时间。这些参数反映了工作记忆的两个领域。实验在海马体损伤（HIPP，n=12）和假手术（CTRL，n=8）大鼠中进行，它们在四天的 APAAT 中接受训练，每天包括四个 5 分钟的阶段：习惯化、第一阶段（st1）和第二阶段（st2）的记忆训练、5 分钟的休息时间，然后进行检索测试。回避区域的位置每天都在变化。HIPP 大鼠在两个记忆训练阶段都受到了损伤，而 CTRL 大鼠在第二阶段的记忆表现显著提高。在 HIPP 大鼠中，作为每个进入次数的电击比率来衡量的认知技能学习受到了损害。海马体损伤并没有损害运动活动。总之，即使是轻微的双侧海马体损伤也会阻止在困难任务中形成工作记忆。
