Webster Paula J, Skipper-Kallal Laura M, Frum Chris A, Still Hayley N, Ward B Douglas, Lewis James W
Blanchette Rockefellar Neurosciences Institute, Department of Neurobiology & Anatomy, West Virginia University Morgantown, WV, USA.
Blanchette Rockefellar Neurosciences Institute, Department of Neurobiology & Anatomy, West Virginia UniversityMorgantown, WV, USA; Department of Neurology, Georgetown University Medical CampusWashington, DC, USA.
Front Neurosci. 2017 Jan 6;10:579. doi: 10.3389/fnins.2016.00579. eCollection 2016.
A major gap in our understanding of natural sound processing is knowledge of where or how in a cortical hierarchy differential processing leads to categorical perception at a semantic level. Here, using functional magnetic resonance imaging (fMRI) we sought to determine if and where cortical pathways in humans might diverge for processing action sounds vs. vocalizations as distinct acoustic-semantic categories of real-world sound when matched for duration and intensity. This was tested by using relatively less semantically complex natural sounds produced by non-conspecific animals rather than humans. Our results revealed a striking double-dissociation of activated networks bilaterally. This included a previously well described pathway preferential for processing vocalization signals directed laterally from functionally defined primary auditory cortices to the anterior superior temporal gyri, and a less well-described pathway preferential for processing animal action sounds directed medially to the posterior insulae. We additionally found that some of these regions and associated cortical networks showed parametric sensitivity to high-order quantifiable acoustic signal attributes and/or to perceptual features of the natural stimuli, such as the degree of perceived recognition or intentional understanding. Overall, these results supported a neurobiological theoretical framework for how the mammalian brain may be fundamentally organized to process acoustically and acoustic-semantically distinct categories of ethologically valid, real-world sounds.
我们对自然声音处理的理解存在一个重大差距，即不清楚在皮质层级结构中，差异处理在何处以及如何导致语义层面的分类感知。在这里，我们使用功能磁共振成像（fMRI）来确定，当动作声音与发声在持续时间和强度上匹配时，作为现实世界声音的不同声学 - 语义类别，人类的皮质通路在处理动作声音与发声时是否以及在何处可能会出现分化。我们通过使用非同种动物而非人类产生的语义相对不太复杂的自然声音来进行测试。我们的结果揭示了双侧激活网络的显著双重分离。这包括一条先前已被充分描述的通路，该通路优先处理从功能定义的初级听觉皮层侧向传导至颞上回前部的发声信号，以及一条描述较少的通路，该通路优先处理向内侧传导至岛叶后部的动物动作声音。我们还发现，这些区域中的一些以及相关的皮质网络对高阶可量化声学信号属性和/或自然刺激的感知特征（如感知识别程度或意图理解）表现出参数敏感性。总体而言，这些结果支持了一个神经生物学理论框架，即哺乳动物大脑可能如何从根本上组织起来以处理在行为学上有效的现实世界声音的声学和声学 - 语义上不同的类别。
