[gus_massa]

>>> LGN cells send a pulse to the visual cortex when they detect a change from dark to light, or vice versa

This looks like an binary toggle encoding (and that the receiving end must remember and count how many pulses received to know if that part is dark or light).

I vaguely remember something like that the neurons in that part or nearby send pulses periodically, and the time between pulses is smaller (or bigger?) when there is more light. (Or perhaps keep the time between pulses, but use double/triple/... pulses more light.) Perhaps add some slow adaptation to the light level, so after a time at a fixed light level the neuron uses the default interval between pulses. I'm not sure about the actual encoding, but all of what I remember are very different from the encoding in the article.