Okay, so, we have another topic here. Color vision. [INAUDIBLE] We talk about actually, this is the history, right? Well, from this [FOREIGN] And the nature actually indeed we got the evidence, right? This is actually people cloned these three, even the color-sensing pigment. It's red, and green, and blue. And also, if you measure the spectrum sensitivity to define the light, your foundation is three sets of this spectrum. [FOREIGN] Cells. But actually later, people also found actually some kind of phenomenons. It's very difficult to explain. Now use just this theory, okay? [FOREIGN] Difficult to explain some phenomenon. So the phenomenon is actually there is no way you can see a greenish red color. [FOREIGN] Okay, or if a bluish yellow [FOREIGN] [FOREIGN] If you only have this kind of three [FOREIGN] For the color vision actually as a lot of debating there, okay. One is actually top of this kind of trichromatic color vision. [FOREIGN] Color opponency [FOREIGN] So red and green is a one component coding, okay? And then another one is blue and the yellow. [FOREIGN]. Indeed, when people do the recording from the ganglion cells or even from the bipolar cell in the retina. People found actually, there is color-opponency coding in the retina. That is actually, for example for a ganglion cell in the center, you give a red light. Then the cell will be excited. If you give green light in this sorround, the cell, they inhibit it, okay? The red, excitation. If you give a uniform actually covers the whole receptive field for this same cell, then you get still get some excitation. That is because you stimulate at the center, right? But if it is surround, because you need green light to cancer. It is not effective so still you have the excitation. But this case, center, red, surround, green and then you have very few spikes, especially in the dark. No signal. So, then this is actually color-opponency coding. I guess it's quite easy for you're to work the mechanism underlying for these color opponency because we already talked about actually the center surround receptive field. Center surround receptive field, actually you recruit the horizontal cell, right, to feed it back. You can imagine if the center for one bipolar cell receives the red light. Red cone input and then the horizontal cell connect the green cones only. And they feed it back to this red cone cell. What would happen to connect the bipolar cell? Then you would have red on, green off, right? This is one of the mechanisms to generate this color-opponency coding. So okay, so then important, okay? So the color information first detected in the eye, in the retina is by three different cone photoreceptors [FOREIGN], okay? But then in the retina, you will further recoded the color information. [FOREIGN] In the brain. So, the color information to your brain is this opponency coding. Because it's ganglion cell sending information to the brain. Ganglion cell, you have this color opponent, of course, in the brain. You'll receive what the color opponence is coding, right?
