Fu Xiaochen, Reinert Janine K, Reuschenbach Josefine, Mago Adam, Lindeman Sander, Fukunaga Izumi
Sensory and Behavioural Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.
iScience. 2025 May 26;28(7):112755. doi: 10.1016/j.isci.2025.112755. eCollection 2025 Jul 18.
The olfactory system is a well-known model for studying the temporal encoding of sensory stimuli due to its rhythmic stimulus delivery through respiration. Sniff-locked activity is pervasive in the primary olfactory area, the olfactory bulb, and is considered critical to structuring the output of its computation. We tested the behavioral importance of these temporal features using simple closed-loop optogenetics embedded in custom behavioral paradigms. We found that mice perceive differences in evoked spike counts and discriminate between synchronous vs. asynchronous activations of the output neurons. Surprisingly, they failed to distinguish the timing of evoked activity relative to the sniff cycle. These results suggest that, beyond the first steps of olfactory processing, sniff rhythms play a more nuanced role, with greater reliance on the spike rate and synchrony for the neural encoding of the environment, consistent with a gradual transformation of encoding format at successive stages of sensory processing.
嗅觉系统是研究感觉刺激的时间编码的一个著名模型，因为它通过呼吸有节奏地传递刺激。嗅锁活动在主要嗅觉区域嗅球中普遍存在，并被认为对构建其计算输出至关重要。我们使用嵌入定制行为范式中的简单闭环光遗传学测试了这些时间特征的行为重要性。我们发现，小鼠能够感知诱发的脉冲计数差异，并区分输出神经元的同步激活与异步激活。令人惊讶的是，它们无法区分诱发活动相对于嗅周期的时间。这些结果表明，除了嗅觉处理的最初步骤之外，嗅节律起着更微妙的作用，在环境的神经编码中对脉冲率和同步性的依赖性更大，这与感觉处理连续阶段编码格式的逐渐转变一致。
