Tapp P Dwight, Siwak Christina T, Estrada Jimena, Holowachuk Daniel, Milgram Norton W
Department of Psychology, University of Toronto, Scarborough, Ontario M1C 1A4, Canada.
Learn Mem. 2003 Mar-Apr;10(2):148-60. doi: 10.1101/lm.56503.
The present study used two versions of a spatial list learning (SLL) paradigm to examine the effects of increased cognitive load on visuospatial working memory processes in young and old beagle dogs. In the first experiment, young, and a select group of old dogs were first presented with one item, then two, and then three, and were rewarded for responding to the novel position. The dogs were able to learn the task at short delays, but compared with young dogs, old dogs performed worse at delays of 10 sec, and could not reach longer delays. Analysis of errors indicated that memory was best for end items in the spatial list and that within sessions, the number of errors in later trials was greater than the number of errors in earlier trials. A second version of the task, a modified SLL (mSLL) was developed to control for the use of non-mnemonic strategies on the SLL task. In this version, the first two items were presented individually. Acquisition and maximal memory performance were better in the young relative to the old dogs. Similar to the original SLL design, memory for early list items was worse than memory for later list items in both young and old dogs. The within-session pattern of errors however, did not change from trial to trial on the mSLL. The present results suggest that multiple working memory processes are engaged during complex tests of visuospatial function and the neuroanatomical substrates controlling these processes are affected differentially by age in the beagle dog.
本研究使用了两种版本的空间列表学习（SLL）范式，以检验认知负荷增加对幼年和老年比格犬视觉空间工作记忆过程的影响。在第一个实验中，先向幼年和一组选定的老年犬呈现一个物品，然后是两个，再然后是三个，并对其对新位置的反应给予奖励。这些犬能够在短延迟情况下学会任务，但与幼年犬相比，老年犬在10秒延迟时表现较差，并且无法达到更长的延迟。错误分析表明，对空间列表中末尾物品的记忆最佳，并且在各实验环节中，后期试验的错误数量多于早期试验的错误数量。开发了该任务的第二个版本，即改良的SLL（mSLL），以控制在SLL任务中使用非记忆策略的情况。在这个版本中，前两个物品是单独呈现的。与老年犬相比，幼年犬的习得和最大记忆表现更好。与原始SLL设计类似，幼年和老年犬对列表早期物品的记忆都比对后期物品的记忆差。然而，在mSLL上，各实验环节中的错误模式在不同试验之间没有变化。目前的结果表明，在视觉空间功能的复杂测试中涉及多种工作记忆过程，并且控制这些过程的神经解剖学基质在比格犬中受到年龄的不同影响。
