Polarity-specific transcranial direct current stimulation disrupts auditory pitch learning
Polarity-specific transcranial direct current stimulation disrupts auditory pitch learning
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DOI：
10.3389/fnins.2015.00174
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发表时间：
2015-05-18
影响因子：
4.3
通讯作者：
Zatorre, Robert J.
中科院分区：
文献类型：
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作者：
Matsushita, Reiko;Andoh, Jamila;Zatorre, Robert J.
经颅直流电刺激（tDCS）因其潜在的治疗用途而引起越来越多的关注。虽然它的影响主要研究运动和视觉任务，但对听觉领域的影响知之甚少。过去对听觉任务的tDCS研究显示了不同的行为结果，可能是由于刺激参数、任务诱发的大脑活动或每项研究中使用的任务测量的差异。因此，需要进一步的研究，使用经过充分验证的任务来澄清tDCS对听觉系统的行为影响。在这里，我们利用了先前功能性磁共振成像研究的结果，该研究表明，在微音调旋律模式的细粒度音高学习过程中，右侧听觉皮层被调制。通过同样的任务，用tDCS瞄准右侧听觉皮层，从而使我们能够测试该区域与音调学习有因果关系的假设。本研究的参与者接受了为期3天的训练，而我们每天使用心理物理阶梯程序使用微调性旋律测量音高辨别阈值。在执行任务的第二天，我们对三组参与者在右侧听觉皮层上进行了阳极、阴极或假tDCS。在3天的训练中，假组和正极组均表现出预期的显著学习效果（音调阈值降低）；相反，我们观察到阳极tDCS对听觉音高学习的阻断作用，因此该组在3天内的阈值没有显着变化。结果支持了右听觉皮层在音高辨别学习中的因果作用。
Transcranial direct current stimulation (tDCS) is attracting increasing interest because of its potential for therapeutic use. While its effects have been investigated mainly with motor and visual tasks, less is known in the auditory domain. Past tDCS studies with auditory tasks demonstrated various behavioral outcomes, possibly due to differences in stimulation parameters, task-induced brain activity, or task measurements used in each study. Further research, using well-validated tasks is therefore required for clarification of behavioral effects of tDCS on the auditory system. Here, we took advantage of findings from a prior functional magnetic resonance imaging study, which demonstrated that the right auditory cortex is modulated during fine-grained pitch learning of microtonal melodic patterns. Targeting the right auditory cortex with tDCS using this same task thus allowed us to test the hypothesis that this region is causally involved in pitch learning. Participants in the current study were trained for 3 days while we measured pitch discrimination thresholds using microtonal melodies on each day using a psychophysical staircase procedure. We administered anodal, cathodal, or sham tDCS to three groups of participants over the right auditory cortex on the second day of training during performance of the task. Both the sham and the cathodal groups showed the expected significant learning effect (decreased pitch threshold) over the 3 days of training; in contrast we observed a blocking effect of anodal tDCS on auditory pitch learning, such that this group showed no significant change in thresholds over the 3 days. The results support a causal role for the right auditory cortex in pitch discrimination learning.