Soyman Efe, Vicario David S
Rutgers University, New Brunswick, New Jersey
Rutgers University, New Brunswick, New Jersey.
J Neurophysiol. 2017 Mar 1;117(3):1266-1280. doi: 10.1152/jn.00462.2016. Epub 2016 Dec 28.
Sensory and motor brain structures work in collaboration during perception. To evaluate their respective contributions, the present study recorded neural responses to auditory stimulation at multiple sites simultaneously in both the higher-order auditory area NCM and the premotor area HVC of the songbird brain in awake zebra finches (). Bird's own song (BOS) and various conspecific songs (CON) were presented in both blocked and shuffled sequences. Neural responses showed plasticity in the form of stimulus-specific adaptation, with markedly different dynamics between the two structures. In NCM, the response decrease with repetition of each stimulus was gradual and long-lasting and did not differ between the stimuli or the stimulus presentation sequences. In contrast, HVC responses to CON stimuli decreased much more rapidly in the blocked than in the shuffled sequence. Furthermore, this decrease was more transient in HVC than in NCM, as shown by differential dynamics in the shuffled sequence. Responses to BOS in HVC decreased more gradually than to CON stimuli. The quality of neural representations, computed as the mutual information between stimuli and neural activity, was higher in NCM than in HVC. Conversely, internal functional correlations, estimated as the coherence between recording sites, were greater in HVC than in NCM. The cross-coherence between the two structures was weak and limited to low frequencies. These findings suggest that auditory communication signals are processed according to very different but complementary principles in NCM and HVC, a contrast that may inform study of the auditory and motor pathways for human speech processing. Neural responses to auditory stimulation in sensory area NCM and premotor area HVC of the songbird forebrain show plasticity in the form of stimulus-specific adaptation with markedly different dynamics. These two structures also differ in stimulus representations and internal functional correlations. Accordingly, NCM seems to process the individually specific complex vocalizations of others based on prior familiarity, while HVC responses appear to be modulated by transitions and/or timing in the ongoing sequence of sounds.
在感知过程中，感觉和运动脑结构协同工作。为了评估它们各自的作用，本研究在清醒的斑胸草雀的鸣禽大脑高阶听觉区域NCM和运动前区HVC中同时记录了多个部位对听觉刺激的神经反应。鸟类自身歌声（BOS）和各种同种歌声（CON）以分块和随机序列呈现。神经反应以刺激特异性适应的形式表现出可塑性，这两个结构之间的动态变化明显不同。在NCM中，随着每个刺激的重复，反应逐渐且持久地下降，并且在不同刺激或刺激呈现序列之间没有差异。相比之下，HVC对CON刺激的反应在分块序列中比在随机序列中下降得更快。此外，如随机序列中的差异动态所示，这种下降在HVC中比在NCM中更短暂。HVC中对BOS的反应比对CON刺激的反应下降得更缓慢。以刺激与神经活动之间的互信息计算的神经表征质量在NCM中高于HVC。相反，以记录部位之间的相干性估计的内部功能相关性在HVC中比在NCM中更大。这两个结构之间的交叉相干性较弱且仅限于低频。这些发现表明，听觉通信信号在NCM和HVC中根据非常不同但互补的原则进行处理，这种对比可能为人类语音处理的听觉和运动通路研究提供信息。鸣禽前脑感觉区域NCM和运动前区HVC对听觉刺激的神经反应以刺激特异性适应的形式表现出可塑性，动态变化明显不同。这两个结构在刺激表征和内部功能相关性方面也存在差异。因此，NCM似乎基于先前的熟悉程度来处理其他个体特定的复杂发声，而HVC的反应似乎受正在进行的声音序列中的转换和/或时间调制。
