Genovesio Aldo, Cirillo Rossella, Tsujimoto Satoshi, Mohammad Abdellatif Sara, Wise Steven P
Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy;
Department of Intelligence Science and Technology, Graduate School of Informatics, Kyoto University, Kyoto, Japan; Nielsen Neuro, Tokyo, Japan; and.
J Neurophysiol. 2015 Jul;114(1):48-56. doi: 10.1152/jn.00057.2015. Epub 2015 Apr 22.
Rhesus monkeys performed two tasks, both requiring a choice between a red square and a blue circle. In the duration task, the two stimuli appeared sequentially on each trial, for varying durations, and, later, during the choice phase of the task, the monkeys needed to choose the one that had lasted longer. In the matching-to-sample task, one of the two stimuli appeared twice as a sample, with durations matching those in the duration task, and the monkey needed to choose that stimulus during the choice phase. Although stimulus duration was irrelevant in the matching-to-sample task, the monkeys made twice as many errors when the second stimulus was shorter. This across-task interference supports an order-dependent model of the monkeys' choice and reveals something about their strategy in the duration task. The monkeys tended to choose the second stimulus when its duration exceeded the first and to choose the alternative stimulus otherwise. For the duration task, this strategy obviated the need to store stimulus-duration conjunctions for both stimuli, but it generated errors on the matching-to-sample task. We examined duration coding in prefrontal neurons and confirmed that a population of cells encoded relative duration during the matching-to-sample task, as expected from the order-dependent errors.
恒河猴执行两项任务，两项任务都要求在红色方块和蓝色圆圈之间做出选择。在时长任务中，每次试验中两个刺激依次出现，时长各不相同，随后，在任务的选择阶段，猴子需要选择持续时间更长的那个。在样本匹配任务中，两个刺激中的一个作为样本出现两次，持续时间与时长任务中的相同，猴子需要在选择阶段选择那个刺激。尽管刺激时长在样本匹配任务中无关紧要，但当第二个刺激较短时，猴子犯的错误是原来的两倍。这种跨任务干扰支持了一种依赖顺序的猴子选择模型，并揭示了它们在时长任务中的策略。当第二个刺激的时长超过第一个时，猴子倾向于选择第二个刺激，否则就选择另一个刺激。对于时长任务，这种策略避免了为两个刺激都存储刺激时长关联信息的需要，但在样本匹配任务中产生了错误。我们检查了前额叶神经元中的时长编码，并证实了一群细胞在样本匹配任务中编码相对时长，正如从依赖顺序的错误中所预期的那样。
