Center for Neural Science, New York University, New York, NY 10003, USA.
Department of Psychology, New York University, New York, NY 10003, USA.
Cereb Cortex. 2021 May 10;31(6):2886-2897. doi: 10.1093/cercor/bhaa396.
Core auditory cortex (AC) neurons encode slow fluctuations of acoustic stimuli with temporally patterned activity. However, whether temporal encoding is necessary to explain auditory perceptual skills remains uncertain. Here, we recorded from gerbil AC neurons while they discriminated between a 4-Hz amplitude modulation (AM) broadband noise and AM rates >4 Hz. We found a proportion of neurons possessed neural thresholds based on spike pattern or spike count that were better than the recorded session's behavioral threshold, suggesting that spike count could provide sufficient information for this perceptual task. A population decoder that relied on temporal information outperformed a decoder that relied on spike count alone, but the spike count decoder still remained sufficient to explain average behavioral performance. This leaves open the possibility that more demanding perceptual judgments require temporal information. Thus, we asked whether accurate classification of different AM rates between 4 and 12 Hz required the information contained in AC temporal discharge patterns. Indeed, accurate classification of these AM stimuli depended on the inclusion of temporal information rather than spike count alone. Overall, our results compare two different representations of time-varying acoustic features that can be accessed by downstream circuits required for perceptual judgments.
核心听觉皮层（AC）神经元通过具有时间模式的活动对声音刺激的缓慢波动进行编码。然而，时间编码是否对于解释听觉感知技能是必要的，这仍然不确定。在这里，我们在沙鼠的 AC 神经元中进行记录，同时它们在 4Hz 幅度调制（AM）宽带噪声和 AM 率 >4Hz 之间进行区分。我们发现一部分神经元具有基于尖峰模式或尖峰计数的神经阈值，其优于记录的会话的行为阈值，这表明尖峰计数可以为这个感知任务提供足够的信息。依赖于时间信息的群体解码器优于仅依赖于尖峰计数的解码器，但尖峰计数解码器仍然足以解释平均行为表现。这使得更苛刻的感知判断可能需要时间信息的可能性仍然存在。因此，我们询问了在 4 到 12Hz 之间准确分类不同 AM 率是否需要包含在 AC 时间放电模式中的信息。事实上，这些 AM 刺激的准确分类取决于时间信息的包含，而不仅仅是尖峰计数。总的来说，我们的结果比较了两种可以通过感知判断所需的下游电路访问的时变声音特征的不同表示形式。
