Eliades Steven J, Wang Xiaoqin
Department of Otorhinolaryngology: Head and Neck Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
Laboratory of Auditory Neurophysiology, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Hear Res. 2017 May;348:98-111. doi: 10.1016/j.heares.2017.03.001. Epub 2017 Mar 9.
During speech, humans continuously listen to their own vocal output to ensure accurate communication. Such self-monitoring is thought to require the integration of information about the feedback of vocal acoustics with internal motor control signals. The neural mechanism of this auditory-vocal interaction remains largely unknown at the cellular level. Previous studies in naturally vocalizing marmosets have demonstrated diverse neural activities in auditory cortex during vocalization, dominated by a vocalization-induced suppression of neural firing. How underlying auditory tuning properties of these neurons might contribute to this sensory-motor processing is unknown. In the present study, we quantitatively compared marmoset auditory cortex neural activities during vocal production with those during passive listening. We found that neurons excited during vocalization were readily driven by passive playback of vocalizations and other acoustic stimuli. In contrast, neurons suppressed during vocalization exhibited more diverse playback responses, including responses that were not predictable by auditory tuning properties. These results suggest that vocalization-related excitation in auditory cortex is largely a sensory-driven response. In contrast, vocalization-induced suppression is not well predicted by a neuron's auditory responses, supporting the prevailing theory that internal motor-related signals contribute to the auditory-vocal interaction observed in auditory cortex.
在说话过程中，人类会持续倾听自己的语音输出，以确保准确交流。这种自我监测被认为需要将有关声音声学反馈的信息与内部运动控制信号整合起来。在细胞水平上，这种听觉-发声相互作用的神经机制在很大程度上仍然未知。先前对自然发声的狨猴的研究表明，在发声过程中听觉皮层存在多种神经活动，主要表现为发声诱导的神经放电抑制。这些神经元潜在的听觉调谐特性如何有助于这种感觉运动处理尚不清楚。在本研究中，我们定量比较了狨猴发声时与被动聆听时听觉皮层的神经活动。我们发现，发声时兴奋的神经元很容易被发声和其他声学刺激的被动回放所驱动。相比之下，发声时受到抑制的神经元表现出更多样化的回放反应，包括那些无法通过听觉调谐特性预测的反应。这些结果表明，听觉皮层中与发声相关的兴奋在很大程度上是一种感觉驱动的反应。相比之下，神经元的听觉反应并不能很好地预测发声诱导的抑制，这支持了一种流行的理论，即与内部运动相关的信号有助于在听觉皮层中观察到的听觉-发声相互作用。
