Supplementary Material for: Microglial characterisation in transient human neurodevelopmental structures

Human neurodevelopment is characterised by the appearance, development and disappearance or transformation of various transient structures that underlie the establishment of connectivity within and between future cortical and subcortical areas. Examples of transient structures in the forebrain (amongst many others) include the subpial granular layer and the subplate zone. We have previously characterised the precise spatiotemporal dynamics of microglia in the human telencephalon. Here, we describe the diversity of microglial morphologies in the subpial granular layer and the subplate zone. Where possible, we couple the predominant morphological phenotype with functional characterisations to infer tentative roles for microglia in a changing neurodevelopmental landscape. We interpret these findings within the context of relevant morphogenetic and neurogenetic events in humans. Due to the unique genetic, molecular and anatomical features of the human brain and because many human neurological and psychiatric diseases have their origins during development, these structures deserve special attention.