Categorical perception is a fundamental cognitive function enabling animals to flexibly assign sounds into behaviorally relevant categories. This study investigates the nature of acoustic category representations, their emergence in an ascending series of ferret auditory and frontal cortical fields, and the dynamics of this representation during passive listening to task-relevant stimuli and during active retrieval from memory while engaging in learned categorization tasks. Ferrets were trained on two auditory Go-NoGo categorization tasks to discriminate two non-compact sound categories (composed of tones or amplitude-modulated noise). Neuronal responses became progressively more categorical in higher cortical fields, especially during task performance. The dynamics of the categorical responses exhibited a cascading top-down modulation pattern that began earliest in the frontal cortex and subsequently flowed downstream to the secondary auditory cortex, followed by the primary auditory cortex. In a subpopulation of neurons, categorical responses persisted even during the passive listening condition, demonstrating memory for task categories and their enhanced categorical boundaries.

中文翻译：

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听觉和额叶皮层中非紧凑声学类别的动力学和分层编码。

类别感知是一种基本的认知功能，使动物能够灵活地将声音分配到行为相关的类别中。本研究调查了声学类别表征的性质、它们在一系列上升的雪貂听觉和额叶皮层场中的出现，以及在被动聆听任务相关刺激和在从事学习分类任务时从记忆中主动检索期间这种表征的动态. 雪貂接受了两项听觉 Go-NoGo 分类任务的训练，以区分两种非紧凑型声音类别（由音调或调幅噪声组成）。神经元反应在更高的皮层区域中逐渐变得更加明确，尤其是在任务执行期间。分类反应的动态表现出级联自上而下的调制模式，最早在额叶皮层开始，随后向下游流向次级听觉皮层，然后是初级听觉皮层。在一个神经元亚群中，即使在被动聆听条件下，分类反应也持续存在，展示了对任务类别的记忆及其增强的分类边界。