Talker adaptation improves speech processing efficiency by reducing possible mappings between talkers' speech acoustics and listeners' phonemic representations. We investigated the functional neuroanatomy of talker adaptation by applying noninvasive neurostimulation (high-definition transcranial direct current stimulation; HD-tDCS) to left superior temporal lobe while participants performed an auditory word identification task. We factorially manipulated talker variability (single vs. mixed talkers) and speech context (isolated words vs. connected speech), measuring listeners' speech processing efficiency under anodal, cathodal, or sham stimulation. Speech processing was faster for single talkers than mixed talkers, and connected speech reduced the additional processing costs associated with mixed-talker speech. However, the beneficial effect of connected speech in the mixed-talker condition was significantly attenuated under both anodal and cathodal stimulation versus sham. Stimulation of left superior temporal lobe disrupts the brain's ability to use local phonetic context to rapidly adapt to a talker, revealing this region's causal role in talker adaptation.

中文翻译：

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左颞叶的无创神经刺激破坏了说话者在语音处理中的快速适应

说话者适应通过减少说话者的语音声学和听众的音素表示之间可能的映射来提高语音处理效率。我们通过在参与者执行听觉单词识别任务时对左上颞叶应用无创神经刺激（高清经颅直流电刺激；HD-tDCS）来研究说话者适应的功能神经解剖学。我们逐级操纵说话者的变异性（单个说话者与混合说话者）和语音上下文（孤立的单词与连接的语音），测量听众在阳极、阴极或假刺激下的语音处理效率。单个说话者的语音处理速度比混合说话者更快，并且连接语音减少了与混合说话者语音相关的额外处理成本。然而，与假刺激相比，在阳极和阴极刺激下，混合说话者条件下连接语音的有益效果均显着减弱。刺激左上颞叶会破坏大脑利用当地语音环境快速适应说话者的能力，揭示了该区域在说话者适应中的因果作用。