Comstock Lindy, Carvalho Vinícius Rezende, Lainscsek Claudia, Fallah Aria, Sejnowski Terrence J
Department of Psychiatry & Biobehavioral Sciences, UCLA, Los Angeles, CA 90095, USA.
Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA 90095, USA.
Brain Sci. 2024 Sep 2;14(9):895. doi: 10.3390/brainsci14090895.
Transcranial magnetic stimulation (TMS) has been widely used to study the mechanisms that underlie motor output. Yet, the extent to which TMS acts upon the cortical neurons implicated in volitional motor commands and the focal limitations of TMS remain subject to debate. Previous research links TMS to improved subject performance in behavioral tasks, including a bias in phoneme discrimination. Our study replicates this result, which implies a causal relationship between electro-magnetic stimulation and psychomotor activity, and tests whether TMS-facilitated psychomotor activity recorded via electroencephalography (EEG) may thus serve as a superior input for neural decoding. First, we illustrate that site-specific TMS elicits a double dissociation in discrimination ability for two phoneme categories. Next, we perform a classification analysis on the EEG signals recorded during TMS and find a dissociation between the stimulation site and decoding accuracy that parallels the behavioral results. We observe weak to moderate evidence for the alternative hypothesis in a Bayesian analysis of group means, with more robust results upon stimulation to a brain region governing multiple phoneme features. Overall, task accuracy was a significant predictor of decoding accuracy for phoneme categories (F(1,135) = 11.51, < 0.0009) and individual phonemes (F(1,119) = 13.56, < 0.0003), providing new evidence for a causal link between TMS, neural function, and behavior.
经颅磁刺激（TMS）已被广泛用于研究运动输出背后的机制。然而，TMS对参与意志性运动指令的皮质神经元的作用程度以及TMS的局部局限性仍存在争议。先前的研究将TMS与行为任务中受试者表现的改善联系起来，包括音素辨别偏差。我们的研究重复了这一结果，这意味着电磁刺激与精神运动活动之间存在因果关系，并测试了通过脑电图（EEG）记录的TMS促进的精神运动活动是否可作为神经解码的更好输入。首先，我们表明特定部位的TMS在两种音素类别的辨别能力上引发了双重解离。接下来，我们对TMS期间记录的EEG信号进行分类分析，发现刺激部位和解码准确性之间的解离与行为结果相似。在对组均值的贝叶斯分析中，我们观察到支持备择假设的证据较弱至中等，对控制多个音素特征的脑区进行刺激时结果更可靠。总体而言，任务准确性是音素类别解码准确性的显著预测指标（F(1,135) = 11.51，< 0.0009）和单个音素解码准确性的显著预测指标（F(1,119) = 13.56，< 0.0003），为TMS、神经功能和行为之间的因果联系提供了新证据。
