Neural Correlate of Pitch in Auditory Cortex

描述(由申请人提供)：将和声相关的音调分组为单一的音高感知是我们的听觉系统处理语音和音乐的重要策略。虽然生理学数据已经证明，处理音调所需的信息存在于皮质下区域，但音调是如何在皮质中处理或表示的仍是未知的。我们计划研究觉醒的恒河猴(Callithrix Jacchus)听觉皮质中音调表征的神经机制。特别是，我们将重点关注嘴区域(R)，这是毗邻初级听觉皮质(AI)的第二个核心区，仍然相对未被探索，可能在处理基音方面发挥重要作用。首先，我们将使用窄带点击训练来研究速率调制作为AI和R中对含有未分辨谐波的刺激的基音的一种可能的显式编码机制。接下来，我们将使用调和和非调和复音来研究速率调制作为一种可能的显式基音编码机制，用于具有分解的谐波的刺激。如果使用这样的机制，我们将确定神经元的首选音调是否按地形组织。此外，我们还将研究神经元之间响应同一基音不同谐波的峰同步，作为一种潜在的基音隐式编码机制。我们的假设是，人工智能处理一般的光谱和时间信息，而R场的神经活动更具体地与音调有关。

DESCRIPTION (provided by applicant): The grouping of harmonically related tones into the single percept of pitch is a salient strategy for processing speech and music by our auditory system. Although physiological data has demonstrated that information necessary for processing pitch is present in subcortical areas, how pitch is processed or represented in cortex remains unknown. We plan to investigate neural mechanisms underlying pitch representation in the auditory cortex of awake marmoset monkeys (Callithrix jacchus). In particular, we will focus on the rostral field (R), a second core area neighboring primary auditory cortex (AI) that remains relatively unexplored and may play an important role in processing pitch. First, we will use narrowband click trains to investigate rate modulation as a possible explicit encoding mechanism of pitch in AI and R for stimuli with unresolved harmonics. Next, we will use harmonic and inharmonic complex tones to investigate rate modulation as a possible explicit encoding mechanism of pitch in AI and R for stimuli with resolved harmonics. If such a mechanism is used, we will determine if a neuron's preferred pitch is topographically organized. In addition, we will investigate spike synchronization between neurons responding to different harmonics of a common pitch, as a potential implicit encoding mechanism of pitch. Our hypothesis is that AI processes general spectral and temporal information, while neural activity in field R is more specifically related to pitch.