Dept. Neurobiology & Anatomy, Univ. of Rochester, Box 603, Rochester, NY 14642, USA.
Hear Res. 2013 Nov;305:135-43. doi: 10.1016/j.heares.2013.07.011. Epub 2013 Jul 26.
Neuronal activity in single prefrontal neurons has been correlated with behavioral responses, rules, task variables and stimulus features. In the non-human primate, neurons recorded in ventrolateral prefrontal cortex (VLPFC) have been found to respond to species-specific vocalizations. Previous studies have found multisensory neurons which respond to simultaneously presented faces and vocalizations in this region. Behavioral data suggests that face and vocal information are inextricably linked in animals and humans and therefore may also be tightly linked in the coding of communication calls in prefrontal neurons. In this study we therefore examined the role of VLPFC in encoding vocalization call type information. Specifically, we examined previously recorded single unit responses from the VLPFC in awake, behaving rhesus macaques in response to 3 types of species-specific vocalizations made by 3 individual callers. Analysis of responses by vocalization call type and caller identity showed that ∼19% of cells had a main effect of call type with fewer cells encoding caller. Classification performance of VLPFC neurons was ∼42% averaged across the population. When assessed at discrete time bins, classification performance reached 70 percent for coos in the first 300 ms and remained above chance for the duration of the response period, though performance was lower for other call types. In light of the sub-optimal classification performance of the majority of VLPFC neurons when only vocal information is present, and the recent evidence that most VLPFC neurons are multisensory, the potential enhancement of classification with the addition of accompanying face information is discussed and additional studies recommended. Behavioral and neuronal evidence has shown a considerable benefit in recognition and memory performance when faces and voices are presented simultaneously. In the natural environment both facial and vocalization information is present simultaneously and neural systems no doubt evolved to integrate multisensory stimuli during recognition. This article is part of a Special Issue entitled "Communication Sounds and the Brain: New Directions and Perspectives".
前额叶单个神经元的活动与行为反应、规则、任务变量和刺激特征有关。在非人类灵长类动物中，已发现腹外侧前额叶皮层（VLPFC）中记录的神经元对特定于物种的发声有反应。先前的研究发现，该区域存在多感觉神经元，它们对同时呈现的面孔和发声有反应。行为数据表明，在动物和人类中，面孔和声音信息是不可分割的，因此在通讯叫声的前额叶神经元编码中也可能紧密相连。在这项研究中，我们因此研究了 VLPFC 在编码发声呼叫类型信息中的作用。具体来说，我们检查了在清醒、行为猕猴中，VLPFC 中以前记录的单个单位对 3 种特定于物种的发声的反应，这些发声由 3 个不同的发声者发出。通过发声呼叫类型和发声者身份分析响应表明，约 19%的细胞具有呼叫类型的主要影响，而较少的细胞编码发声者。VLPFC 神经元的分类性能在整个群体中平均约为 42%。在离散时间箱中评估时，在第一个 300 毫秒内，对于鸣叫的分类性能达到 70%，并且在响应期间保持高于机会水平，尽管对于其他呼叫类型的性能较低。鉴于只有发声信息存在时，大多数 VLPFC 神经元的分类性能不佳，以及最近的证据表明大多数 VLPFC 神经元是多感觉的，因此讨论了添加伴随的面部信息对分类的潜在增强作用，并建议进行额外的研究。行为和神经证据表明，当同时呈现面孔和声音时，在识别和记忆性能方面有相当大的益处。在自然环境中，面部和发声信息同时存在，并且神经系统无疑在识别过程中进化为整合多感觉刺激。本文是题为“通讯声音与大脑：新方向与观点”的特刊的一部分。
