Introduction

As we vocalize, our brains generate predictions of the sounds we produce to enable suppression of neural responses when intentions match vocalizations and to make adjustments when they do not. This may be instantiated by efference copy and corollary discharge mechanisms, which are impaired in people with schizophrenia (SZ). Although innate, these mechanisms can be affected by intentions. We asked if attending to pitch during vocalizations would take these mechanisms “off-line” and reduce suppression.

Methods

Event-related potentials (ERP) were recorded from 96 SZ and 92 healthy controls (HC) as they vocalized triplets in monotone (Phrase) or sang triplets in ascending thirds (Pitch). Pre-vocalization activity (Bereitschaftspotential, BP), N1, and P2 ERP components to sounds were compared during vocalization and playback.

Results

N1 was not as suppressed during Pitch as during Phrase. N1 suppression was not affected by SZ in either task when all data were collapsed across pitches (Pitch) and positions (Phrase). However, when binned according to vocalization performance, SZ showed less N1 suppression than HC at longer (>2 s) inter-stimulus intervals (Phrase) and inconsistent suppression across pitches (Pitch). Unlike N1, P2 was more suppressed during Pitch than Phrase and not affected by SZ. BP was greater during vocalization than playback but did not contribute to N1 or P2 effects. Pitch variability was inversely related to negative symptoms.

Conclusions

Neural processing is not suppressed when patients and controls sing, and corollary discharge abnormalities in schizophrenia are only seen at long vocalization intervals.

中文翻译：

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发声和歌唱揭示精神分裂症的必然放电功能的复杂模式

介绍

当我们发声时，我们的大脑会预测我们产生的声音，以便在意图与发声匹配时抑制神经反应，并在不匹配时进行调整。这可能是由精神分裂症 (SZ) 患者受损的情感复制和必然放电机制所实例化的。尽管是天生的，但这些机制可能会受到意图的影响。我们询问在发声期间注意音高是否会使这些机制“脱机”并减少抑制。

方法

从 96 名 SZ 和 92 名健康对照 (HC) 记录事件相关电位 (ERP)，因为他们以单调 (Phrase) 发声三连音或以升三度 (音高) 唱三连音。在发声和播放过程中比较了发声前活动（Bereitschaftspotential，BP）、N1 和 P2 ERP 组件与声音。

结果

N1 在 Pitch 期间不像在 Phrase 期间那样受到抑制。当所有数据在音高 (Pitch) 和位置 (Phrase) 之间折叠时，N1 抑制在任一任务中都不受 SZ 的影响。然而，当根据发声表现进行分组时，SZ 在较长（> 2 秒）的刺激间间隔（短语）和跨音高（音高）的不一致抑制下表现出比 HC 更少的 N1 抑制。与 N1 不同，P2 在 Pitch 期间比 Phrase 受到更多抑制，不受 SZ 影响。发声期间的 BP 比播放时更大，但对 N1 或 P2 效果没有贡献。音高变异性与阴性症状呈负相关。

结论

当患者和对照者唱歌时，神经处理不会受到抑制，精神分裂症的必然放电异常仅在较长的发声间隔中才会出现。