Hage Steffen R, Nieder Andreas
Animal Physiology, Institute of Neurobiology, University of Tübingen, 72076 Tübingen, Germany
Animal Physiology, Institute of Neurobiology, University of Tübingen, 72076 Tübingen, Germany.
J Neurosci. 2015 May 6;35(18):7030-40. doi: 10.1523/JNEUROSCI.2371-14.2015.
Complex audio-vocal integration systems depend on a strong interconnection between the auditory and the vocal motor system. To gain cognitive control over audio-vocal interaction during vocal motor control, the PFC needs to be involved. Neurons in the ventrolateral PFC (VLPFC) have been shown to separately encode the sensory perceptions and motor production of vocalizations. It is unknown, however, whether single neurons in the PFC reflect audio-vocal interactions. We therefore recorded single-unit activity in the VLPFC of rhesus monkeys (Macaca mulatta) while they produced vocalizations on command or passively listened to monkey calls. We found that 12% of randomly selected neurons in VLPFC modulated their discharge rate in response to acoustic stimulation with species-specific calls. Almost three-fourths of these auditory neurons showed an additional modulation of their discharge rates either before and/or during the monkeys' motor production of vocalization. Based on these audio-vocal interactions, the VLPFC might be well positioned to combine higher order auditory processing with cognitive control of the vocal motor output. Such audio-vocal integration processes in the VLPFC might constitute a precursor for the evolution of complex learned audio-vocal integration systems, ultimately giving rise to human speech.
复杂的听觉-发声整合系统依赖于听觉系统与发声运动系统之间的紧密连接。为了在发声运动控制过程中获得对听觉-发声交互的认知控制，前额叶皮质（PFC）需要参与其中。腹外侧前额叶皮质（VLPFC）中的神经元已被证明分别对发声的感觉认知和运动产生进行编码。然而，PFC中的单个神经元是否反映听觉-发声交互尚不清楚。因此，我们记录了恒河猴（猕猴）VLPFC中的单神经元活动，同时它们根据指令发声或被动聆听猴叫声。我们发现，VLPFC中随机选择的12%的神经元会根据特定物种叫声的声学刺激来调节其放电率。这些听觉神经元中近四分之三在猴子发声运动之前和/或期间其放电率还会有额外的调节。基于这些听觉-发声交互，VLPFC可能处于将高阶听觉处理与发声运动输出的认知控制相结合的有利位置。VLPFC中的这种听觉-发声整合过程可能构成复杂的习得性听觉-发声整合系统进化的前身，并最终产生人类语言。
