Center for Neuroprosthetics, Swiss Federal Institute of Technology (EPFL), CH-1202 Geneva, Switzerland.
Brain Mind Institute, Faculty of Life Sciences, Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland.
J Neurosci. 2021 Oct 27;41(43):8917-8927. doi: 10.1523/JNEUROSCI.3164-20.2021. Epub 2021 Sep 8.
Previous studies have shown that self-generated stimuli in auditory, visual, and somatosensory domains are attenuated, producing decreased behavioral and neural responses compared with the same stimuli that are externally generated. Yet, whether such attenuation also occurs for higher-level cognitive functions beyond sensorimotor processing remains unknown. In this study, we assessed whether cognitive functions such as numerosity estimations are subject to attenuation in 56 healthy participants (32 women). We designed a task allowing the controlled comparison of numerosity estimations for self-generated (active condition) and externally generated (passive condition) words. Our behavioral results showed a larger underestimation of self-generated compared with externally generated words, suggesting that numerosity estimations for self-generated words are attenuated. Moreover, the linear relationship between the reported and actual number of words was stronger for self-generated words, although the ability to track errors about numerosity estimations was similar across conditions. Neuroimaging results revealed that numerosity underestimation involved increased functional connectivity between the right intraparietal sulcus and an extended network (bilateral supplementary motor area, left inferior parietal lobule, and left superior temporal gyrus) when estimating the number of self-generated versus externally generated words. We interpret our results in light of two models of attenuation and discuss their perceptual versus cognitive origins. We perceive sensory events as less intense when they are self-generated compared with when they are externally generated. This phenomenon, called attenuation, enables us to distinguish sensory events from self and external origins. Here, we designed a novel fMRI paradigm to assess whether cognitive processes such as numerosity estimations are also subject to attenuation. When asking participants to estimate the number of words they had generated or passively heard, we found bigger underestimation in the former case, providing behavioral evidence of attenuation. Attenuation was associated with increased functional connectivity of the intraparietal sulcus, a region involved in numerosity processing. Together, our results indicate that the attenuation of self-generated stimuli is not limited to sensory consequences but is also impact cognitive processes such as numerosity estimations.
先前的研究表明，与外部产生的相同刺激相比，听觉、视觉和体感领域的自我产生的刺激会被削弱，从而导致行为和神经反应降低。然而，这种衰减是否也会发生在感觉运动加工之外的更高层次的认知功能上仍然未知。在这项研究中，我们评估了 56 名健康参与者（32 名女性）的认知功能，如数量估计，是否会受到衰减的影响。我们设计了一项任务，允许对自我产生的（主动条件）和外部产生的（被动条件）单词的数量估计进行受控比较。我们的行为结果表明，与外部产生的单词相比，自我产生的单词被低估得更厉害，这表明自我产生的单词的数量估计受到了衰减。此外，尽管自我产生和外部产生单词的数量估计的错误追踪能力在条件间相似，但自我产生单词的报告数量和实际数量之间的线性关系更强。神经影像学结果表明，当估计自我产生与外部产生的单词数量时，数量低估涉及右顶内沟与扩展网络（双侧辅助运动区、左顶下小叶和左颞上回）之间的功能连接增加。我们根据两种衰减模型来解释我们的结果，并讨论其感知与认知起源。与外部产生的刺激相比，当我们自我产生感官事件时，我们会觉得它们的强度降低。这种现象称为衰减，使我们能够将感官事件与自我和外部来源区分开来。在这里，我们设计了一个新的 fMRI 范式来评估数量估计等认知过程是否也受到衰减的影响。当要求参与者估计他们生成或被动听到的单词数量时，我们在前一种情况下发现了更大的低估，为衰减提供了行为证据。衰减与顶内沟的功能连接增加有关，顶内沟是一个参与数量处理的区域。总之，我们的结果表明，自我产生的刺激的衰减不仅限于感官后果，还会影响数量估计等认知过程。
