Neural Tube Organoids: A Novel System to Study Developmental Timing.

The neural tube (NT) is a transient structure formed during embryogenesis which develops into the brain and spinal cord. While mouse models have been commonly used in place of human embryos to study NT development, species-specific differences limit their applicability. One major difference is developmental timing, with NT formation from the neural plate in 16 days in humans compared to 4 days in mice, as well as differences in the time taken to form neuronal subtypes and complete neurogenesis. Neural tube organoids (NTOs) represent a new way to study NT development in vitro. While mouse and human NTOs have been shown to recapitulate the major developmental events of NT formation; it is unknown whether species-specific developmental timing, also termed allochrony, is also recapitulated. This review summarises current research using both mouse and human NTOs and compares developmental timing events in order to assess if allochrony is maintained in organoids.