Operational hub cells: a morpho-physiologically diverse class of GABAergic neurons united by a common function.

GABAergic microcircuits structure the activation of neuronal ensembles that support most cortical computations. Because of the heterogeneous nature of the GABAergic cell community, a full understanding of structure-function relationships in these microcircuits may be hampered by a reductionist approach that consists of classifying them according to an exhaustive collection of parameters. It therefore could be beneficial to our understanding of these complex cells to also consider other approaches. Thus, graph theory has recently taught us that biological networks often include hub nodes that are essential for information flow, and ensuing experimental evidence has demonstrated the existence of 'operational' hub neurons. So far, only GABAergic neurons have been identified as 'operational hubs', further emphasizing their critical function in controlling cortical network dynamics.