Early enucleation does not alter the gross morphology of identified projection neurons in the chicken optic tectum

During development of the nervous system, neurotrophic interactions are essential for the synchronization of substructures such as retina and visual midbrain. However, morphological studies of postsynaptic elements after ablation of afferents are sparse. We investigated the effect of uni- and bilateral eye anlagen removal on identified projection neurons in the chicken optic tectum. Without retinal input, neurons in the stratum griseum centrale express their specific cell adhesions molecules, retain large dendritic fields and form specialized dendritic endings; however, the latter are deformed and extend over a much larger area. Our results show that even monosynaptically innervated tectal neurons develop largely independently from trophic retinal inputs and only become dependent on these after synaptic contact with retinal afferents.