CORTICAL MECHANISMS OF AUDITORY PERCEPTION AND MEMORY

听觉和记忆的皮质机制

• 批准号: 6432791
• 负责人: MORTIMER MISHKIN
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF MENTAL HEALTH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6432791
• 关键词: Macaca mulatta; auditory cortex; auditory discrimination; brain mapping; experimental brain lesion; memory; neural information processing; sound frequency

Monkeys were trained on an auditory version of delayed matching-to-sample with randomly varying delays of 2-50 sec and retested after being given different types of bilateral temporal lobe lesions. Monkeys that received complete medial temporal removals or removal of only the rostral third of the superior temporal gyrus (STG) were severely impaired even at the shortest delays; whereas those given lesions limited to the rhinal (i.e. perirhinal/entorhinal) cortices, which are known to produce severe impairment in both visual and tactile recognition, were unaffected even at the longest delays. Our results suggest that the critical neural substrates for recognition in the auditory and visual modalities are anatomically distinct within the temporal lobe. The deficit in auditory recognition following medial temporal lesions may be due to a disconnection between the STG and other critical areas for memory function located outside the temporal lobe.To identify all the regions, both inside and outside the temporal lobe, that might participate in auditory processing, those regions activated during passive listening to a variety of auditory stimuli were mapped using 2-deoxyglucose autoradiography. The activated regions were found to include the entire extent of the superior temporal gyrus (STG), from its caudal tip to the temporal pole, the parahippocampal gyrus, and many extratemporal areas in the posterior parietal, insular, and prefrontal cortices. Our recent anatomical study shows that the auditory regions in prefrontal cortex receive strong projections from the STG (Romanski et al., Nature Neuroscience 2: 1131-6, 1999), strengthening the hypothesis that a disconnection between STG and prefrontal regions may account for the deficit in auditory recognition memory following medial temporal lesions. An important aspect of auditory processing is the spectral and temporal integration of acoustic information. To examine spectrotemporal integration in the primary auditory cortex of an awake rhesus monkey, we recorded neuronal responses to (a) pure tones and bandpassed noise in order to obtain frequency tuning curves (FTCs), (b) ripple stimuli in order to generate spectrotemporal receptive fields (STRFs), and (c) linear frequency modulated (FM) stimuli, which are natural components of monkey calls. In addition to the typical phasic onset responses observed in the anesthetized animal, primary cortical neurons in the awake monkey showed a variety of temporally structured types of response, including tonic, pauser, and offset responses, which appear to have different distributions in the two primary auditory areas, A1 and R. We also found evidence for greater spectral integration in primary auditory cortex than has previously been described in the anesthetized monkey. Although most of the neurons in the primary auditory cortex respond preferentially to a single best frequency, some neurons (10-15%) show multiple tuning peaks both in their FTCs and STRFs, suggesting that these neurons integrate spectral information over a wide range of frequencies, which is likely to be important in mediating auditory pattern recognition. Also, 75% of A1 and R neurons were selective for FM direction and/or rate, with response distributions suggesting that rate and directionality are independently represented in monkey primary auditory cortex.

猴子接受了延迟匹配样本的听觉版本，其随机变化的延迟为2-50秒，并在给予不同类型的双侧颞叶病变后进行了重新测试。 即使在最短的延迟下，也会严重受损的次颞内侧移动或仅移除上部颞上三分之一的猴子。虽然那些限于鼻中（即周围/内嗅）皮质的病变，但已知在视觉和触觉识别中会产生严重损害的皮质，即使在最长的延迟下也不会受到影响。 我们的结果表明，在听觉和视觉方式中识别的关键神经底物在颞叶中在解剖学上是不同的。 内侧时间病变后听觉识别的不足可能是由于STG与位于颞叶外部内存功能的其他关键领域之间的分离。确定所有区域内部和外部的时间叶子可能参与听觉处理，这些区域可能会参与听觉处理，这些区域在使用多种听觉刺激的过程中激活了这些区域。 发现活化区域包括从尾端到颞极的颞上回（STG）的整个范围，偏头痛以及后顶叶，岛状和前额叶皮质的许多颞外区域。 我们最近的解剖研究表明，前额叶皮层中的听觉区域从STG获得了强大的预测（Romanski等人，自然神经科学2：1131-6，1999），增强了以下假设：STG和前额叶​​区域之间的分离可能会导致听觉识别记忆的不足，这可能是听觉识别记忆的不足。听觉处理的一个重要方面是声学信息的光谱和时间整合。 为了检查清醒恒河猴的主要听觉皮层中的光谱量化整合，我们记录了对（a）纯音和带噪声的神经元反应，以获得频率调谐曲线（FTC），（b）为了产生频谱的刺激，以产生光谱刺激，以产生频谱的刺激（strul fiens）（strul formul）（strul formul forme forme forme forme forme and funsure（c），（c c）linfor fullfs（c）line（c c）linfore（c），（c c）linfore（c c）linfore（c c）。猴子的电话。 除了在麻醉动物中观察到的典型的体质发作反应外，清醒猴子中的主要皮质神经元还显示出各种时间结构的反应类型，包括滋补，pauser和Octsoct响应，这些反应似乎在两个主要的听觉库里群中发现了两个主要的听觉分布，它们在两个主要的听觉区域中似乎具有不同的证据。 尽管主要听觉皮层中的大多数神经元优先响应单个最佳频率，但一些神经元（10-15％）在其FTC和STRF中显示了多个调谐峰，这表明这些神经元在广泛的频率上整合了光谱信息，这对于调解听觉模式认识很重要。 同样，有75％的A1和R神经元在FM方向和/或速率方面具有选择性，响应分布表明速率和方向性在猴子主要听觉皮层中独立表示。