Bagur Sophie, Bourg Jacques, Kempf Alexandre, Tarpin Thibault, Bergaoui Khalil, Guo Yin, Ceballo Sebastian, Schwenkgrub Joanna, Verdier Antonin, Puel Jean Luc, Bourien Jérôme, Bathellier Brice
Université Paris Cité, Institut Pasteur, AP-HP, Inserm, Fondation Pour l'Audition, Institut de l'Audition, IHU reConnect, F-75012 Paris, France.
Institut des Neurosciences de Montpellier, Université de Montpellier, INSERM, Montpellier, France.
Sci Adv. 2025 Jan 10;11(2):eadr6214. doi: 10.1126/sciadv.adr6214. Epub 2025 Jan 8.
The temporal structure of sensory inputs contains essential information for their interpretation. Sensory cortex represents these temporal cues through two codes: the temporal sequences of neuronal activity and the spatial patterns of neuronal firing rate. However, it is unknown which of these coexisting codes causally drives sensory decisions. To separate their contributions, we generated in the mouse auditory cortex optogenetically driven activity patterns differing exclusively along their temporal or spatial dimensions. Mice could rapidly learn to behaviorally discriminate spatial but not temporal patterns. Moreover, large-scale neuronal recordings across the auditory system revealed that the auditory cortex is the first region in which spatial patterns efficiently represent temporal cues on the timescale of several hundred milliseconds. This feature is shared by the deep layers of neural networks categorizing time-varying sounds. Therefore, the emergence of a spatial code for temporal sensory cues is a necessary condition to efficiently associate temporally structured stimuli with decisions.
感觉输入的时间结构包含了对其进行解读的关键信息。感觉皮层通过两种编码来呈现这些时间线索：神经元活动的时间序列以及神经元放电率的空间模式。然而，目前尚不清楚这些共存的编码中哪一种因果性地驱动了感觉决策。为了区分它们各自的作用，我们在小鼠听觉皮层中通过光遗传学手段产生了仅在时间或空间维度上不同的活动模式。小鼠能够快速学会在行为上区分空间模式，但无法区分时间模式。此外，对整个听觉系统的大规模神经元记录显示，听觉皮层是第一个在几百毫秒的时间尺度上空间模式能够有效表征时间线索的区域。对随时间变化的声音进行分类的神经网络深层也具有这一特征。因此，出现用于时间感觉线索的空间编码是将时间结构的刺激与决策有效关联起来的必要条件。
