When might the brain go wrong: the role of immune cells at critical time-points during development

The Melbourne Neuropsychiatry Centre (MNC) is undertaking leading research in neuropsychiatric disorders, with an emphasis on longitudinal brain imaging studies to identify neurobiological risk and resilience markers of illness in humans. Clinical research has revealed that altered connectivity underlies many neuropsychiatric disorders from depression to autism and schizophrenia. This finding directly implicates the brain’s synapses, which are the main method by which neurons communicate with each other and supporting glial cells. Key players in the development of synaptic connections are the brain’s immune cells, the microglia. Microglia are responsible for protecting the brain against invading pathogens but also crucially for pruning dysfunctional or under-utilised synapses during development and beyond. Notably, microglial dysfunction is implicated in many neuropsychiatric and neurodevelopmental disorders. It is therefore hypothesised that aberrant microglial pruning during development is having diverse effects on synapse formation and functioning that lead to the connectivity deficits identified in these disorders. However, to date the effect of microglial activity on the normal developing brain has not been extensively explored with reference to specific neurodevelopmental stages.