Prete David A, Heikoop David, McGillivray Joshua E, Reilly James P, Trainor Laurel J
Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, Ontario, Canada.
Department of Electrical and Computer Engineering, McMaster University, Hamilton, Ontario, Canada.
Eur J Neurosci. 2022 Apr;55(8):1972-1985. doi: 10.1111/ejn.15660. Epub 2022 Apr 17.
The human auditory system excels at detecting patterns needed for processing speech and music. According to predictive coding, the brain predicts incoming sounds, compares predictions to sensory input and generates a prediction error whenever a mismatch between the prediction and sensory input occurs. Predictive coding can be indexed in electroencephalography (EEG) with the mismatch negativity (MMN) and P3a, two components of event-related potentials (ERP) that are elicited by infrequent deviant sounds (e.g., differing in pitch, duration and loudness) in a stream of frequent sounds. If these components reflect prediction error, they should also be elicited by omitting an expected sound, but few studies have examined this. We compared ERPs elicited by infrequent randomly occurring omissions (unexpected silences) in tone sequences presented at two tones per second to ERPs elicited by frequent, regularly occurring omissions (expected silences) within a sequence of tones presented at one tone per second. We found that unexpected silences elicited significant MMN and P3a, although the magnitude of these components was quite small and variable. These results provide evidence for hierarchical predictive coding, indicating that the brain predicts silences and sounds.
人类听觉系统擅长检测处理语音和音乐所需的模式。根据预测编码理论，大脑会预测传入的声音，将预测结果与感官输入进行比较，每当预测与感官输入之间出现不匹配时，就会产生预测误差。预测编码可以通过脑电图（EEG）中的失配负波（MMN）和P3a进行索引，这是事件相关电位（ERP）的两个成分，由频繁声音流中不常见的异常声音（例如音高、持续时间和响度不同）引发。如果这些成分反映了预测误差，那么遗漏预期声音也应该会引发它们，但很少有研究对此进行过考察。我们将以每秒两个音调呈现的音调序列中不常见的随机出现的遗漏（意外静音）所引发的ERP与以每秒一个音调呈现的音调序列中频繁出现的、有规律出现的遗漏（预期静音）所引发的ERP进行了比较。我们发现，意外静音会引发显著的MMN和P3a，尽管这些成分的幅度相当小且变化不定。这些结果为分层预测编码提供了证据，表明大脑会预测静音和声音。
