Perrodin Catherine, Kayser Christoph, Logothetis Nikos K, Petkov Christopher I
Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany;
Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QB, United Kingdom;
Proc Natl Acad Sci U S A. 2015 Jan 6;112(1):273-8. doi: 10.1073/pnas.1412817112. Epub 2014 Dec 22.
When social animals communicate, the onset of informative content in one modality varies considerably relative to the other, such as when visual orofacial movements precede a vocalization. These naturally occurring asynchronies do not disrupt intelligibility or perceptual coherence. However, they occur on time scales where they likely affect integrative neuronal activity in ways that have remained unclear, especially for hierarchically downstream regions in which neurons exhibit temporally imprecise but highly selective responses to communication signals. To address this, we exploited naturally occurring face- and voice-onset asynchronies in primate vocalizations. Using these as stimuli we recorded cortical oscillations and neuronal spiking responses from functional MRI (fMRI)-localized voice-sensitive cortex in the anterior temporal lobe of macaques. We show that the onset of the visual face stimulus resets the phase of low-frequency oscillations, and that the face-voice asynchrony affects the prominence of two key types of neuronal multisensory responses: enhancement or suppression. Our findings show a three-way association between temporal delays in audiovisual communication signals, phase-resetting of ongoing oscillations, and the sign of multisensory responses. The results reveal how natural onset asynchronies in cross-sensory inputs regulate network oscillations and neuronal excitability in the voice-sensitive cortex of macaques, a suggested animal model for human voice areas. These findings also advance predictions on the impact of multisensory input on neuronal processes in face areas and other brain regions.
当群居动物进行交流时，一种模态中信息内容的起始相对于另一种模态会有很大差异，例如视觉或面部动作先于发声出现时。这些自然发生的异步现象不会破坏可懂度或感知连贯性。然而，它们发生的时间尺度可能会以尚不清楚的方式影响整合性神经元活动，尤其是对于那些神经元对交流信号表现出时间上不精确但高度选择性反应的层级下游区域。为了解决这个问题，我们利用了灵长类动物发声中自然发生的面部和声音起始异步现象。以这些现象作为刺激，我们记录了猕猴颞叶前部功能性磁共振成像（fMRI）定位的声音敏感皮层的皮质振荡和神经元放电反应。我们发现视觉面部刺激的起始会重置低频振荡的相位，并且面部 - 声音异步会影响两种关键类型的神经元多感官反应的显著程度：增强或抑制。我们的研究结果表明，视听交流信号中的时间延迟、持续振荡的相位重置以及多感官反应的符号之间存在三方关联。结果揭示了跨感官输入中的自然起始异步如何调节猕猴声音敏感皮层中的网络振荡和神经元兴奋性，猕猴被认为是人类语音区域的动物模型。这些发现也推进了关于多感官输入对面部区域和其他脑区神经元过程影响的预测。
