Alleman Matteo, Panichello Matthew, Buschman Timothy J, Johnston W Jeffrey
Center for Theoretical Neuroscience.
Mortimer B. Zuckerman Mind, Brain, and Behavior Institute Columbia University, New York, NY, USA.
bioRxiv. 2023 Oct 23:2023.10.09.561584. doi: 10.1101/2023.10.09.561584.
When making decisions in a cluttered world, humans and other animals often have to hold multiple items in memory at once - such as the different items on a shopping list. Psychophysical experiments in humans and other animals have shown remembered stimuli can sometimes become confused, with participants reporting chimeric stimuli composed of features from different stimuli. In particular, subjects will often make "swap errors" where they misattribute a feature from one object as belonging to another object. While swap errors have been described behaviorally, their neural mechanisms are unknown. Here, we elucidate these neural mechanisms through trial-by-trial analysis of neural population recordings from posterior and frontal brain regions while monkeys perform two multi-stimulus working memory tasks. In these tasks, monkeys were cued to report the color of an item that either was previously shown at a corresponding location (requiring selection from working memory) or will be shown at the corresponding location (requiring attention to a position). Animals made swap errors in both tasks. In the neural data, we find evidence that the neural correlates of swap errors emerged when correctly remembered information is selected incorrectly from working memory. This led to a representation of the distractor color as if it were the target color, underlying the eventual swap error. We did not find consistent evidence that swap errors arose from misinterpretation of the cue or errors during encoding or storage in working memory. These results suggest an alternative to established views on the neural origins of swap errors, and highlight selection from and manipulation in working memory as crucial - yet surprisingly brittle - neural processes.
在纷繁复杂的世界中做出决策时，人类和其他动物常常需要同时在记忆中留存多个事物——比如购物清单上的不同物品。针对人类和其他动物的心理物理学实验表明，被记住的刺激有时会变得混淆，参与者会报告由来自不同刺激的特征组成的嵌合刺激。特别是，受试者常常会犯“交换错误”，即他们将一个物体的特征错误地归属于另一个物体。虽然交换错误已经从行为角度进行了描述，但其神经机制尚不清楚。在这里，我们通过对猴子执行两项多刺激工作记忆任务时后脑和额叶脑区神经群体记录进行逐次试验分析，阐明了这些神经机制。在这些任务中，猴子被提示报告一个物品的颜色，该物品要么先前在相应位置展示过（需要从工作记忆中进行选择），要么将在相应位置展示（需要关注一个位置）。动物在两项任务中都出现了交换错误。在神经数据中，我们发现证据表明，当从工作记忆中错误地选择正确记住的信息时，交换错误的神经关联就会出现。这导致了干扰物颜色的表征，就好像它是目标颜色一样，这是最终交换错误的基础。我们没有找到一致的证据表明交换错误是由于对提示的错误解读或在工作记忆的编码或存储过程中出现的错误导致的。这些结果为关于交换错误神经起源的既定观点提供了一种替代解释，并突出了工作记忆中的选择和操作作为关键——但出人意料地脆弱——的神经过程。
