larval neuron small undifferentiated primary neuron 2020-05-29T08:52:05Z pioneer neuron Primary neuron found in the embryo or larva that remains in an undifferentiated state during early larval stages (Andrade et al., 2019). They have a simple, thin, unbranched process that enters the neuropil, but lacks output synapses (Andrade et al., 2019). At least some of these differentiate into mature adult neurons during late larval and pupal stages (Andrade et al., 2019). In the first instar brain, there are around 802 of these neurons, which is more than 25% of brain primary neurons (Andrade et al., 2019). VFB:FBbt_00049543 fly_anatomy.ontology embryonically born secondary neuron primary SU neuron FBbt:00049543 immature primary neuron