The midbrain is a subcortical area involved in central functions such as
integrating sensory modalities, movement initiation and bottom-up and
top-down attention. In chicken, the midbrain roof is termed optic tectum
(TeO) and consists of 15 layers with distinct in- and output regions.
Visual input targets the superficial layers, while auditory input
terminates in deeper layers. It has been shown that ablation of sensory
epithelia leads to changes in the cellular patterning and structural
organization of the sensory pathways. For the tectum, ablation of the
eye anlagen was shown to affect retinorecipient neurons. While the gross
morphology remained intact after enucleation, the shape of dendritic
endings was changed presumably due to missing presynaptic input during
synaptic pruning.
We investigated the effect of deafferentation in a multisensory cell
type, the Shepherd's crook neuron (SCN) in the TeO. SCNs have distinct
dendritic branches in retinorecipient layers (superficial layers 1 to 5
and 7) and in layers where auditory input terminates. To assess whether
removal of a single sensory input only affects the dendrites recipient
for that input, we removed the eye anlagen and retrogradely labeled SCNs
later in embryogenesis to visualize the morphology in lesioned and
non-lesioned embryos. We found no changes in the gross morphology or in
the basal dendrites, but an altered growth of the fine structures at the
apical dendrite of SCNs in the retinorecipient layers. Our data indicate
that the neuronal morphology of SCNs is mostly predefined before retinal
innervation affect the fine structure. (C) 2018 Elsevier B.V. All rights
reserved.
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The midbrain is a subcortical area involved in central functions such as
integrating sensory modalities, movement initiation and bottom-up and
top-down attention. In chicken, the midbrain roof is termed optic tectum
(TeO) and consists of 15 layers with distinct in- and output regions.
Visual input targets the superficial layers, while auditory input
terminates in deeper layers. It has been shown that ablation of sensory
epithelia leads to changes in the cellular patterning and structural
organiz...
»