Loss of Postnatal Retinal Input Perturbs Cortical Lamination in the Developing Ferret Visual Cortex

Area of Science:

• Neuroscience
• Developmental Biology
• Ophthalmology

Background:

• Activity-dependent processes shape visual system development.
• Early blindness in humans and animal models shows altered visual cortex structure.
• The precise impact of lost retinal activity on visual cortex organization is not fully understood.

Purpose of the Study:

• To investigate the effects of early bilateral enucleation on primary visual cortex (V1) development in ferrets.
• To characterize cytoarchitectural changes and inhibitory neuron populations in V1 post-enucleation.
• To understand the time course of these alterations during postnatal development.

Main Methods:

• Bilateral enucleation performed on postnatal day 7 (P7) in ferrets.
• Comparative analysis of V1 thickness and cytoarchitecture between enucleated and control animals from P20 to P38.
• Quantification of the number and distribution of major inhibitory neuron populations.

Main Results:

• V1 thickness increased in enucleated ferrets compared to controls by P32.
• Macroscopic anatomical development was perturbed, but interneuron numbers and distribution showed minor changes.
• Developmental trajectories of visual input-dependent organization differed between control and enucleated groups.

Conclusions:

• Postnatal enucleation induces significant and lasting alterations in visual cortex organization.
• These findings in ferrets may model changes seen in early blind humans.
• Results highlight challenges for developing restorative therapies for early vision loss.