Leiden Institute of Brain and Cognition and Leiden Institute of Psychological Research, Leiden University, Leiden, The Netherlands.
PLoS One. 2011;6(5):e18307. doi: 10.1371/journal.pone.0018307. Epub 2011 May 19.
When we speak, we provide ourselves with auditory speech input. Efficient monitoring of speech is often hypothesized to depend on matching the predicted sensory consequences from internal motor commands (forward model) with actual sensory feedback. In this paper we tested the forward model hypothesis using functional Magnetic Resonance Imaging. We administered an overt picture naming task in which we parametrically reduced the quality of verbal feedback by noise masking. Presentation of the same auditory input in the absence of overt speech served as listening control condition. Our results suggest that a match between predicted and actual sensory feedback results in inhibition of cancellation of auditory activity because speaking with normal unmasked feedback reduced activity in the auditory cortex compared to listening control conditions. Moreover, during self-generated speech, activation in auditory cortex increased as the feedback quality of the self-generated speech decreased. We conclude that during speaking early auditory cortex is involved in matching external signals with an internally generated model or prediction of sensory consequences, the locus of which may reside in auditory or higher order brain areas. Matching at early auditory cortex may provide a very sensitive monitoring mechanism that highlights speech production errors at very early levels of processing and may efficiently determine the self-agency of speech input.
当我们说话时，我们会给自己提供听觉言语输入。人们通常假设，高效的言语监控依赖于将内部运动指令（前馈模型）产生的预测感觉后果与实际感觉反馈相匹配。在本文中，我们使用功能磁共振成像来检验前馈模型假说。我们进行了一项显性图片命名任务，通过噪声掩蔽参数化降低言语反馈的质量。在没有显性言语的情况下呈现相同的听觉输入作为聆听控制条件。我们的结果表明，预测和实际感觉反馈之间的匹配会导致听觉活动的抑制消除，因为与聆听控制条件相比，用正常的未掩蔽反馈说话会减少听觉皮层的活动。此外，在自我产生言语时，随着自我产生言语的反馈质量降低，听觉皮层的激活增加。我们得出结论，在说话过程中，早期听觉皮层参与将外部信号与内部产生的模型或感觉后果的预测相匹配，其位置可能位于听觉或更高阶的脑区。在早期听觉皮层的匹配可能提供了一种非常敏感的监测机制，可以在非常早期的处理水平上突出言语产生的错误，并有效地确定言语输入的自我代理。
