Final answer:
Neurons in the visual cortex of very young kittens predominantly respond to vertical lines. This response reflects the neurons' programming and the visual system's reliance on changes in retinal activity for signal encoding.
Step-by-step explanation:
Most of the neurons in the visual cortex of very young kittens respond to vertical lines. The development of the visual system in kittens involves a critical period where input is essential for proper neuronal connection development. Experiments with kittens have shown that if they are deprived of visual input in one eye during this critical period, other areas of the visual cortex can compensate, which highlights the plasticity of the developing brain. This indicates a preference for vertical lines in the visual cortex during early development, which may correspond to the way neurons are programmed to respond to the environment. It's not just the presence or absence of visual stimuli that neurons react to, but rather changes in retinal activity. The process of lateral inhibition, where horizontal cells in the retina inhibit more distant photoreceptors and bipolar cells, sharpens edges and enhances contrast, helping the visual system to encode signals more efficiently.