Complexity and temporal dynamics of frequency coding in the awake rat auditory cortex
Complexity and temporal dynamics of frequency coding in the awake rat auditory cortex
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DOI：
10.1046/j.1460-9568.2003.03007.x
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发表时间：
2003-11-01
影响因子：
3.4
通讯作者：
Ostwald, J
中科院分区：
文献类型：
--
作者：
Gaese, BH;Ostwald, J
听觉皮层神经元是将声音分解为频谱和时间信息的神经网络的组成部分。特别是对它们的频率选择性进行了详细的研究。大多数研究使用麻醉制剂，发现主要是简单的v形调谐。从醒着的动物身上获得的少量数据表明，在那里可以找到更复杂形式的频谱接受场，即频率响应区。我们使用统计评估方法研究了清醒大鼠初级听觉皮层的频率响应区域，发现除了经典的v形调谐外，许多神经元中还存在复杂形式的频率响应区域，包括几个独立的亚区。用窄带噪声确定的响应区域与用纯音测量的响应区域非常相似。它们的宽度与白噪声刺激的反应强度密切相关。这些结果表明，频率响应区的兴奋亚区是神经元的主要特征，也与处理更复杂类型的刺激有关。研究频率响应区域的光谱时间动力学表明，除了典型的on反应外，大约三分之一的神经元表现出持久的兴奋或抑制成分。抑制通常持续时间较长，主要发生在初始兴奋性反应范围以外的频率范围。这些结果表明，清醒动物的听觉皮层神经元可以代表相当不同复杂性的光谱时间信息。
Auditory cortical neurons are elements of a neuronal network that decomposes sounds into spectral and temporal information. In particular, their frequency selectivity has been investigated in great detail. Most studies used anaesthetized preparations and found mainly simple V-shaped tuning. The few data available from awake animals indicate that more complex forms of spectral receptive fields, i.e. frequency response areas, can be found there. We investigated frequency response areas in the awake rat primary auditory cortex using statistical evaluation and found complex forms of frequency response areas with several separate subregions in many neurons, besides classical V-shaped tuning. Response areas, as determined with narrow band noise, were very similar to those measured with pure tones. Their width was well correlated to the response strength to white noise stimulation. These results suggest that the excitatory subregions of frequency response areas were the neurons' predominant characteristic, relevant also for the processing of more complex types of stimuli. Investigating the spectrotemporal dynamics of frequency response areas revealed that approximately one-third of the neurons showed long-lasting excitatory or inhibitory components in addition to the typical ON-response. Inhibition was usually of longer duration and occurred mainly in frequency ranges outside the range of initial excitatory responses. These results indicate that auditory cortical neurons in awake animals can represent spectrotemporal information of rather different complexity.