Umeå Center for Functional Brain Imaging, Umeå University, 901 87 Umeå, Sweden.
Department of Integrative Medical Biology, Physiology Section, Umeå University, 901 87 Umeå, Sweden.
Cereb Cortex. 2023 Feb 20;33(5):2287-2301. doi: 10.1093/cercor/bhac208.
Two critical features of working memory are the identification and appropriate use of task-relevant information while avoiding distraction. Here, in 3 experiments, we explored if these features can be achieved also for nonconscious stimuli. Participants performed a delayed match-to-sample task in which task relevance of 2 competing stimuli was indicated by a cue, and continuous flash suppression was used to manipulate the conscious/nonconscious visual experience. Experiment 1 revealed better-than-chance performance with nonconscious stimuli, demonstrating goal-directed use of nonconscious task-relevant information. Experiment 2 demonstrated that the cue that defined task relevance must be conscious to allow such goal-directed use. In Experiment 3, multi-voxel pattern analyses of brain activity revealed that only the target was prioritized and maintained during conscious trials. Conversely, during nonconscious trials, both target and distractor were maintained. However, decoding of task relevance during the probe/test phase demonstrated identification of both target and distractor information. These results show that identification of task-relevant information can operate also on nonconscious material. However, they do not support the prioritization of nonconscious task-relevant information, thus suggesting a mismatch in the attentional mechanisms involved during conscious and nonconscious working memory.
工作记忆的两个关键特征是在识别和适当使用与任务相关的信息的同时避免分心。在这里,我们通过 3 个实验来探索这些特征是否也可以应用于非意识刺激。参与者执行延迟匹配样本任务,其中两个竞争刺激的任务相关性由提示指示,同时使用连续闪光抑制来操纵意识/非意识的视觉体验。实验 1 表明,即使是非意识刺激,也能表现出优于偶然的成绩,这证明了对非意识任务相关信息的目标导向使用。实验 2 表明,定义任务相关性的提示必须是有意识的,才能允许这种目标导向的使用。在实验 3 中,大脑活动的多体素模式分析表明,只有目标在意识试验中被优先和保持。相反,在非意识试验中,目标和干扰项都被保持。然而,在探测/测试阶段对任务相关性的解码表明,目标和干扰项信息都被识别。这些结果表明,对任务相关信息的识别也可以作用于非意识材料。然而,它们并不支持非意识任务相关信息的优先级化,因此表明在意识和非意识工作记忆中涉及的注意力机制存在不匹配。