Multi-scale study of auditory scene analysis in the ventral auditory pathway

描述(申请人提供)：声音感知和听觉场景分析被认为是由腹侧听觉通路介导的，包括核心听觉皮质，听觉皮质的内侧外侧和前外侧带区域，以及腹外侧额前皮质。相比之下，背侧听觉通路被认为介导空间和听觉运动行为，包括核心听觉皮质，听觉皮质的尾外侧和尾内侧带区域，以及顶叶和额叶皮质。我们目前对这些通路在听觉场景分析和听觉感知中的作用的了解非常有限。这项拨款提案的首要目标是确定系统级、电路级和层级 听觉大脑的特定属性，有助于声音感知和听觉场景分析。为了实现这一目标，猴子将参与一项“声音检测”任务，这要求它们检测嵌入到由其他音串组成的听觉序列中的“目标”音串。通过系统地操纵序列的光谱和空间属性，我们改变了猴子能够检测到目标的概率。该任务提供了一种听觉场景分析的客观行为测量，因为只有当序列被分成两个听觉流时才能检测到目标音调突发。当猴子参与这项任务时，神经活动被记录在一个(在特定目标#1)或两个同时(在特定目标#2)大脑区域，使用多个接触的线性阵列电极。电极垂直于皮质板层插入，使我们能够表征神经活动在每个大脑区域的层状分布。对于每个皮质 我们测试了神经活动(即，单一单位活动和神经群体反应[例如，多单位活动])与猴子行为表现之间的相关性。具体目标#1确定听觉皮质中的神经回路，该回路调节空间信息与光谱信息的整合，以形成听觉场景的知觉表征。具体目标#2确定前额叶皮质和听觉皮质之间的前馈和反馈连接对听觉场景分析的神经机制和计算的不同贡献。无论是单独的还是集体的，特定的目标都为声音感知和听觉场景分析的神经基础提供了有价值的、定量的见解。

DESCRIPTION (provided by applicant): Sound perception and auditory scene analysis are thought to be mediated by the ventral auditory pathway, including core auditory cortex, the medial lateral and anterolateral belt regions of auditory cortex, and the ventrolateral prefrontal cortex. The dorsal auditory pathway, in contrast, is thought to mediate spatial and audiomotor behaviors and includes core auditory cortex, the caudolateral and caudomedial belt regions of auditory cortex, and the parietal and frontal cortices. Our current knowledge regarding the roles of these pathways in auditory scene analysis and auditory perception is very limited. The overarching goal of this grant proposal is to identify the systems-level, circuit-level, and lamina specific properties of the auditory brain that contribute to sound perception and auditory scene analysis. To achieve this goal, monkeys will participate in a "sound-detection" task, which requires them to detect a "target" tone burst that is embedded within an auditory sequence comprised of other tone bursts. By systematically manipulating the spectral and spatial attributes of the sequence, we change the probability that the monkey can detect the target. This task provides an objective behavioral measure of auditory scene analysis because the target tone burst can only be detected when the sequence is segregated into two auditory streams. While the monkey is participating in this task, neural activity is recorded in one (in Specific Aim #1) or two simultaneously (in Specific Aim #2) brain regions using multi-contact, linear-array electrodes. Electrodes are inserted orthogonal to the cortical laminae to enable us to characterize the laminar distribution of neural activity in each brain region. For each cortical lamina and brain region, we test the correlation between neural activity (i.e., single-unit activit and neural-population responses [e.g., multi-unit activity]) and the monkey's behavioral performance. Specific Aim #1 identifies the neural circuitry in auditory cortex that mediates the integration of spatial information with spectral information to form perceptual representations of an auditory scene. Specific Aim #2 identifies the differential contributions of feedforward versus feedback connections between the prefrontal cortex and the auditory cortex to the neural mechanisms and computations underlying auditory scene analysis. Individually and collectively, the Specific Aims provide valuable, quantitative insights into neural bases of sound perception and auditory scene analysis.