University of California, Berkeley, San Francisco Graduate Program in Bioengineering, CA, USA.
J Neurophysiol. 2011 Apr;105(4):1908-17. doi: 10.1152/jn.01055.2010. Epub 2011 Feb 9.
We analyzed the receptive field information conveyed by interspike intervals (ISIs) in the auditory cortex. In the visual system, different ISIs may both code for different visual features and convey differing amounts of stimulus information. To determine their potential role in auditory signal processing, we obtained extracellular recordings in the primary auditory cortex (AI) of the cat while presenting a dynamic moving ripple stimulus and then used the responses to construct spectrotemporal receptive fields (STRFs). For each neuron, we constructed three STRFs, one for short-ISI events (ISI < 15 ms); one for isolated, long-ISI events (ISI > 15 ms); and one including all events. To characterize stimulus encoding, we calculated the feature selectivity and event information for each of the STRFs. Short-ISI spikes were more feature selective and conveyed information more efficiently. The different ISI regimens of AI neurons did not represent different stimulus features, but short-ISI spike events did contribute over-proportionately to the full spike train STRF information. Thus short-ISIs constitute a robust representation of auditory features, and they are particularly effective at driving postsynaptic activity. This suggests that short-ISI events are especially suited to provide noise immunity and high-fidelity information transmission in AI.
我们分析了听觉皮层中尖峰间隔（ISIs）传递的感受野信息。在视觉系统中，不同的 ISI 可能既可以对不同的视觉特征进行编码，又可以传递不同数量的刺激信息。为了确定它们在听觉信号处理中的潜在作用，我们在猫的初级听觉皮层（AI）中获取了细胞外记录，同时呈现了动态移动波纹刺激，然后使用响应构建了频谱时间感受野（STRFs）。对于每个神经元，我们构建了三个 STRFs，一个用于短 ISI 事件（ISI < 15 ms）；一个用于孤立的长 ISI 事件（ISI > 15 ms）；一个包括所有事件。为了描述刺激编码，我们计算了每个 STRF 的特征选择性和事件信息。短 ISI 尖峰的特征选择性更强，信息传递效率更高。AI 神经元的不同 ISI 方案并不代表不同的刺激特征，但短 ISI 尖峰事件确实对全尖峰序列 STRF 信息有不成比例的贡献。因此，短 ISI 构成了听觉特征的稳健表示，它们特别有效地驱动突触后活动。这表明短 ISI 事件特别适合在 AI 中提供噪声免疫和高保真信息传输。
