ASTROCYTIC NETWORKS DEFINE NEURONAL ENSEMBLES ENCODING SENSORY FEATURES

Cortical processing of sensory stimuli depends on the efficient transfer of information within the cortical column. When specific patterns of activity propagate across layers, they selectively depolarize subsets of L5 neurons. This creates ensemble-specific activation, where only neurons receiving coherent translaminar input participate. Here, we determined that astrocyte networks contribute to this translaminar communication to influence sensory behavior. Using in vivo imaging of the mouse somatosensory cortex during freely moving behavior, we demonstrate that astrocytes are organized into vertically connected networks spanning from supragranular to infragranular layers, enabling columnar Ca²⁺ propagation during sensory processing. Disruption of these astrocytic networks in vivo reduced the efficiency of translaminar information flow, resulting in diminished selectivity of layer 5 pyramidal neurons for fine texture discrimination and recruitment of previously unresponsive neurons. This led to an expansion of the active neuronal ensemble that decreased stimulus selectivity and impaired tactile encoding behavior. Together, our findings reveal a critical role for astrocytic networks in facilitating translaminar information transfer and preserving the fidelity of cortical sensory representations.