Final answer:
Blocking NMDA receptors during visual system development disrupts ocular dominance column formation and could lead to abnormalities in the visual cortex, impairing binocular vision and depth perception.
Step-by-step explanation:
If NMDA receptors in the primary visual cortex were blocked throughout visual system development, the formation of ocular dominance columns would likely be disrupted. NMDA receptors play a crucial role in synaptic plasticity, which is essential for the development of the visual system. During a critical period of visual development, neural connections are refined based on sensory input. Blocking NMDA receptors would prevent the normal activity-dependent strengthening and weakening of synapses, leading to abnormal organization of the visual cortex.
In an adult visual system that has developed without functional NMDA receptors in the primary visual cortex, we might expect to see differences from the normal adult visual system. For one, the ocular dominance columns may not form properly, resulting in impaired binocular vision and depth perception. There could also be deficits in visual perception and processing, similar to the effects seen in experiments where kittens were deprived of visual input from one eye during development, leading to the occupation of deprived-eye cortical space by the other eye. This disruption in the normal development could potentially lead to a condition similar to prosopagnosia, as the visual processing pathways have not been correctly established.
Historical experiments, such as those involving kittens with one eye sutured shut and subjects wearing prism glasses, demonstrate the visual system's flexibility and the importance of sensory input during the critical period of development. Therefore, blocking NMDA receptors can have significant long-term effects on visual system function.