Massoudi Roohollah, Van Wanrooij Marc M, Versnel Huib, Van Opstal A John
Department of Biophysics, Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Department of Biophysics, Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands; Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Centre Nijmegen, P.O. Box 9101 HB Nijmegen, The Netherlands.
PLoS One. 2015 Feb 13;10(2):e0116118. doi: 10.1371/journal.pone.0116118. eCollection 2015.
So far, most studies of core auditory cortex (AC) have characterized the spectral and temporal tuning properties of cells in non-awake, anesthetized preparations. As experiments in awake animals are scarce, we here used dynamic spectral-temporal broadband ripples to study the properties of the spectrotemporal receptive fields (STRFs) of AC cells in awake monkeys. We show that AC neurons were typically most sensitive to low ripple densities (spectral) and low velocities (temporal), and that most cells were not selective for a particular spectrotemporal sweep direction. A substantial proportion of neurons preferred amplitude-modulated sounds (at zero ripple density) to dynamic ripples (at non-zero densities). The vast majority (>93%) of modulation transfer functions were separable with respect to spectral and temporal modulations, indicating that time and spectrum are independently processed in AC neurons. We also analyzed the linear predictability of AC responses to natural vocalizations on the basis of the STRF. We discuss our findings in the light of results obtained from the monkey midbrain inferior colliculus by comparing the spectrotemporal tuning properties and linear predictability of these two important auditory stages.
到目前为止，大多数关于核心听觉皮层（AC）的研究都描述了非清醒、麻醉状态下细胞的频谱和时间调谐特性。由于在清醒动物身上进行的实验很少，我们在此使用动态频谱-时间宽带涟漪来研究清醒猴子AC细胞的频谱时间感受野（STRF）特性。我们发现，AC神经元通常对低涟漪密度（频谱）和低速度（时间）最为敏感，并且大多数细胞对特定的频谱时间扫描方向没有选择性。相当一部分神经元更喜欢调幅声音（在零涟漪密度时）而非动态涟漪（在非零密度时）。绝大多数（>93%）的调制传递函数在频谱和时间调制方面是可分离的，这表明时间和频谱在AC神经元中是独立处理的。我们还基于STRF分析了AC对自然发声反应的线性可预测性。通过比较这两个重要听觉阶段的频谱时间调谐特性和线性可预测性，我们根据从猴子中脑下丘获得的结果来讨论我们的发现。
