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Résumé |
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. Moreover, neural networks
allowed to explore the constraints on this process linked to neural
architecture Therefore, the emergence of a spatial code for temporal
sensory cues is a necessary condition to efficiently associate
temporally structured stimuli with decisions. |
