Neural Correlate of Pitch in Auditory Cortex

描述（由申请人提供）：将和谐相关的音调组合成一个单一的音高感知是我们听觉系统处理语音和音乐的重要策略。尽管生理数据已经证明，处理音高所需的信息存在于皮层下区域，但如何在皮层中处理或表征音高仍然未知。我们计划研究清醒绒猴听觉皮层中音调表征的神经机制。我们将特别关注吻侧区(R)，这是与初级听觉皮层（AI）相邻的第二个核心区域，相对而言尚未被探索，可能在音高处理中发挥重要作用。首先，我们将使用窄带点击序列来研究速率调制作为AI和R中具有未解析谐波的刺激的可能的显式编码机制。接下来，我们将使用谐波和非谐波复杂音调来研究速率调制作为AI和R中具有分辨谐波刺激的音调的可能显式编码机制。如果使用这种机制，我们将确定神经元的首选音高是否具有地形组织。此外，我们将研究神经元对共同音高的不同谐波的响应之间的脉冲同步，作为一个潜在的隐含的音高编码机制。我们的假设是，人工智能处理一般的频谱和时间信息，而领域R的神经活动更具体地与音调相关。

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.