Speech and Hearing Science, Arizona State University, Tempe, AZ, USA; Department of Communication Sciences and Disorders, Saint Louis University, Saint Louis, MO, USA.
Speech and Hearing Science, Arizona State University, Tempe, AZ, USA.
Clin Neurophysiol. 2019 Nov;130(11):2182-2192. doi: 10.1016/j.clinph.2019.07.028. Epub 2019 Aug 12.
A recent functional magnetic resonance imaging (fMRI) study of adults with dyslexia showed a general deficit in suppressing responses to various types of repetitive stimuli. This diminished neural adaptation may interfere with implicit learning and forming stable word representations. With fMRI, spatial but not temporal characteristics of the adaptation response could be identified. We address this knowledge gap using event-related potentials.
Fourteen adults with dyslexia and 14 controls participated in an auditory gating paradigm using tone pairs. Response amplitudes and latencies for N1 and P2 were measured. Participants also compared word pairs consisting of identical or subtly different words, a task requiring stable word representations.
Only the controls showed a robust gating effect in an attenuated N1 response to the second tone relative to the first. The dyslexia group was less accurate than the controls in detecting word differences. The N1 gating magnitude was associated with this detection accuracy.
Neural adaptation occurs by approximately 100 ms after stimulus presentation and is diminished in adults with dyslexia. This complements fMRI findings of relevant brain regions by implying a time window representing sensory and pre-attentive auditory processes.
The association between gating magnitude and word discrimination contributes to a neurophysiological account of underspecified word representations.
最近一项针对阅读障碍成年人的功能性磁共振成像（fMRI）研究表明，他们普遍存在抑制对各种类型重复刺激反应的缺陷。这种神经适应能力的下降可能会干扰内隐学习和形成稳定的单词表征。通过 fMRI，可以识别适应反应的空间而非时间特征。我们使用事件相关电位来解决这一知识空白。
14 名阅读障碍成年人和 14 名对照参与者参与了使用双音的听觉门控范式。测量 N1 和 P2 的反应幅度和潜伏期。参与者还比较了由相同或略有不同的单词组成的单词对，这是一项需要稳定单词表征的任务。
只有对照组在相对于第一个音调的第二个音调的 N1 反应中表现出强烈的门控效应。阅读障碍组在检测单词差异方面的准确性低于对照组。N1 门控幅度与这种检测准确性相关。
神经适应在刺激呈现后约 100 毫秒发生，并在阅读障碍成年人中减弱。这通过暗示代表感觉和前注意听觉过程的时间窗口，补充了相关脑区的 fMRI 发现。
门控幅度与单词辨别之间的关联有助于对内隐学习和形成稳定的单词表征。
