School of Psychology, UNSW Sydney, Sydney, Australia; Research School of Psychology, Australian National University, Canberra, Australia.
School of Psychology, UNSW Sydney, Sydney, Australia.
Neuroimage. 2019 Sep;198:170-180. doi: 10.1016/j.neuroimage.2019.04.038. Epub 2019 Apr 16.
When we move our articulator organs to produce overt speech, the brain generates a corollary discharge that acts to suppress the neural and perceptual responses to our speech sounds. Recent research suggests that inner speech - the silent production of words in one's mind - is also accompanied by a corollary discharge. Here, we show that this corollary discharge contains information about the temporal and physical properties of inner speech. In two experiments, participants produced an inner phoneme at a precisely-defined moment in time. An audible phoneme was presented 300 ms before, concurrently with, or 300 ms after participants produced the inner phoneme. We found that producing the inner phoneme attenuated the N1 component of the event-related potential - an index of auditory cortex processing - but only when the inner and audible phonemes occurred concurrently and matched on content. If the audible phoneme was presented before or after the production of the inner phoneme, or if the inner phoneme did not match the content of the audible phoneme, there was no attenuation of the N1. These results suggest that inner speech is accompanied by a temporally-precise and content-specific corollary discharge. We conclude that these results support the notion of a functional equivalence between the neural processes that underlie the production of inner and overt speech, and may provide a platform for identifying inner speech abnormalities in disorders in which they have been putatively associated, such as schizophrenia.
当我们移动发音器官来产生显性言语时，大脑会产生一种伴随发射，以抑制我们言语声音的神经和感知反应。最近的研究表明，内在言语——在头脑中默默地说出单词——也伴随着伴随发射。在这里，我们表明这种伴随发射包含了内在言语的时间和物理性质的信息。在两项实验中，参与者在一个精确定义的时间点内产生内在的音素。一个可听见的音素在参与者产生内在音素之前 300 毫秒、同时或之后 300 毫秒呈现。我们发现，产生内在音素会减弱事件相关电位的 N1 成分——听觉皮层处理的指标——但只有当内在音素和可听见的音素同时发生且内容匹配时才会减弱。如果可听见的音素在产生内在音素之前或之后呈现，或者如果内在音素与可听见的音素的内容不匹配，则 N1 不会减弱。这些结果表明，内在言语伴随着时间精确且内容特定的伴随发射。我们得出结论，这些结果支持了内在言语和显性言语产生所依赖的神经过程之间的功能等同性的概念，并可能为在假定与之相关的精神分裂症等障碍中识别内在言语异常提供一个平台。
