Astrocytes in the retinorecipient superior colliculus display unique cellular and structural properties

Astrocytes have long been considered to be a largely homogeneous cell population. Recent studies however suggest that astrocytes are highly adapted to the local neuronal circuitry. Glucose utilization in the retinorecipient superior colliculus (SC) is one of the highest in the brain. Since metabolic support to neurons is a major function of astrocytes, they could be of particular relevance in this region and display specific features. However, little is known about astrocytes and their interactions with neurons in this multisensory brain area. We thus here investigated region-specific cellular and structural properties of astrocytes in the visual layer of the SC. Using morphological reconstructions, fluorescent recovery after photobleaching (FRAP) and superresolution imaging, we found that astrocytes from the visual layers of the SC are highly distinct with a higher cellular density, a more complex morphology and a stronger proximity to synapses compared to astrocytes from the primary visual cortex and the hippocampus. These data point to astroglial diversity and specialization within neural circuits integrating sensory information in the adult brain.