GrahamH wrote:

DavidMcC wrote:

GrahamH wrote:This digression into particulars of neural activity is of no significance to the topic

Ha! It was you that started talking about neurons "constantly firing"!

Quote me!

Sorry, Graham, I seem to have mixed you up with crank (his post #441 refers to neurons "firing all the time").

DavidMcC wrote:

romansh wrote:

GrahamH wrote:This digression into particulars of neural activity is of no significance to the topic.

Short, to the point and accurate.

Yeah, it's easy to be "accurate" when you're not saying anything much.

Then perhaps you can succinctly address the topic under discussion.

romansh wrote:

DavidMcC wrote:

romansh wrote:

GrahamH wrote:This digression into particulars of neural activity is of no significance to the topic.

Short, to the point and accurate.

Yeah, it's easy to be "accurate" when you're not saying anything much.

Then perhaps you can succinctly address the topic under discussion.

I was addressing the side-issue on "constantly firing" neurons, brought up by crank,. Perhaps you should direct your question to him.

romansh wrote:

DavidMcC wrote:

romansh wrote:

GrahamH wrote:This digression into particulars of neural activity is of no significance to the topic.

Short, to the point and accurate.

Yeah, it's easy to be "accurate" when you're not saying anything much.

Then perhaps you can succinctly address the topic under discussion.

I think the topic is this:

It's 6 months since Christmas and my poinsettias still have red leaves. Is this a true claim?

scott1328 wrote:

romansh wrote:

DavidMcC wrote:

romansh wrote:
Short, to the point and accurate.

Yeah, it's easy to be "accurate" when you're not saying anything much.

Then perhaps you can succinctly address the topic under discussion.

I think the topic is this:

It's 6 months since Christmas and my poinsettias still have red leaves. Is this a true claim?

If we agree on a common nomenclature, yes.

But that is not topic under discussion.

DavidMcC wrote:

GrahamH wrote:

DavidMcC wrote:

GrahamH wrote:This digression into particulars of neural activity is of no significance to the topic

Ha! It was you that started talking about neurons "constantly firing"!

Quote me!

Sorry, Graham, I seem to have mixed you up with crank (his post #441 refers to neurons "firing all the time").

I think you're doing too many Grahams of crank, moderation is important! Too much crank takes its toll, as I've been told by numerous people, really really numerous people.

I don't believe you're understanding something about the ganglion cells. For starters, what is the purpose of a 1-to-1 mapping? Buffering? Amplification? No, I think there is something you're either missing or mistaking. Plus, I really really doubt there is anything about position encoded in any way, it would be completely useless information, redundant, zero information content. Which nerve the info is coming in on informs on its position.

The ganglion cells, if I remember, take in lots of outputs of rods and cones, a whole arbor if you want, and, I didn't get this right earlier, there is a great deal of overlap, meaning a given patch of retina will feed a number of ganglia, in a probably complex, but more or less regular way. Groups of ganglia in that first layer are sensitive to different types of signals in the patterns contained in the image on the retina and I believe the various ganglia also do a lot of communication amongst themselves in a given layer. I really don't want to go try to relearn about all of this, it's quite fascinating, and I'd end up spending a long long time doing this unable to tear myself away long past the time needed for this narrow issue and I don't have that time. The subsequent ganglion layer is fed similarly and extracts higher-order patterns and same again in the third, if there is a third. The foveal ganglia should act the same, there would just needs be a lot more ganglia in a given area, to match the increased density of rods there or cones, the color-sensitive guys.

crank wrote:

DavidMcC wrote:

GrahamH wrote:

DavidMcC wrote:
Ha! It was you that started talking about neurons "constantly firing"!

Quote me!

Sorry, Graham, I seem to have mixed you up with crank (his post #441 refers to neurons "firing all the time").

I think you're doing too many Grahams of crank, moderation is important! Too much crank takes its toll, as I've been told by numerous people, really really numerous people.

I don't believe you're understanding something about the ganglion cells. For starters, what is the purpose of a 1-to-1 mapping? Buffering? Amplification? No, I think there is something you're either missing or mistaking.

Really? What would that be. I would love to know what it is that Í'm "mssing or mistaking". Please do tell.

really doubt there is anything about position encoded in any way, it would be completely useless information, redundant, zero information content. Which nerve the info is coming in on informs on its position.

It is in the method of encoding, as implied in the previously linked article.

The ganglion cells, if I remember, take in lots of outputs of rods and cones, a whole arbor if you want, and, I didn't get this right earlier, there is a great deal of overlap, meaning a given patch of retina will feed a number of ganglia, in a probably complex, but more or less regular way. ...

The function of ganglion cells is to act as the output stage of the retina, and transmit the signal to the brain's LGN, via the optic nerve axons. The multiple connections between most RGCs and photoerecetors is simply a consequence of the minimization of the number of axons in the optic nerve, The quality of our peripheral vison is poor as a result, but our central vision is scanned around (by a form of saccadal movement) to fill in the information gap.

... You do understand, don't you, that there is a big difference between the fovea centralis and the rest of the retina? The former is made up of close-packed cone cells, and provides our best vision in terms of colour and spatial resolution (the latter because there is no arbour for these cells) - the article only talks in general about RGCs, with no mention of the fovea being any different, which is an oversight in the article, AFAIAC.

You obviously blew it with the rate thing, right? And you're doing it again now, what does this mean: "The multiple connections between most RGCs and photoerecetors is simply a consequence of the minimization of the number of axons in the optic nerve"? Simply? Only? You're just going to blithely ignore that a huge amount of data reduction has occurred? The article quoted discusses the layers in the retina, with a picture even:

Structure of the retina. (A) Section of the retina showing overall arrangement of retinal layers. (B) Diagram of the basic circuitry of the retina. A three-neuron chain—photoreceptor, bipolar cell, and ganglion cell—provides the most direct route for transmitting visual information to the brain. Horizontal cells and amacrine cells mediate lateral interactions in the outer and inner plexiform layers, respectively. The terms inner and outer designate relative distances from the center of the eye (inner, near the center of the eye; outer, away from the center, or toward the pigment epithelium).

No exception for the fovea. Not understanding the massive signal processing and data reduction that occurs in the ganglia misses crucial issues. The rods' and cones' are in no way connected directly, in a one to one manner, to the optic nerve, they are subject to the same compression, meaning many to one ultimate ganglion output. There are two linked articles on the previous page, I can find nothing about encoding for position. You've misread something again, rather grossly, I think. Try to explain why such an encoding would be useful, why can't the brain know the position based on which nerves are sending the info> It's valueless info because it's redundant info, highly inefficient to waste resources to create and transmit those data.

OK, I came to the conclusuion that crank's rediculous post above was just anotjhert attempt to get me to insult him. I didn't bite, just decided that this site wasn't worth bothering with, if that is all it can come up with.
A. Of course the basic kind of circuitry is the same in the fovea as elseswhere in the retina - what is different is the arbour - in the FC, it is an arnouir of one, which is how you get better quality vision in that area. I would have thought it was obvious to anyone who knows the first thing about the retina.
B. I did not claim that rods and cones are connected directly - it was you grossly misreading my posts, not me grossly misreading the standard texts on the retina!
C. The position encoding thatbI think is the exaplanation of the otherwise mysterious spike patterns is only necessary outside of the FC, because the arbour makes it possiblle (and useful) to minimize the blurring that they cause. Obviopuisly, the brain cannot tell the exact positition of each photorecptorjust fron whichg axon it is connected to when there are a hundred times as many photoreceptors as axons! Again, I thought that was obvious.

Just came across this .. thought it was interesting.

romansh wrote:Just came across this .. thought it was interesting.

It is interesting. It does seem to be basically how we adapt to unusual colour balance, rather than anything to do with expectation that strawberries should be red.

Original:



Applying global colour balance I get this:



Masking out some spots I get this:



So the human visual system is doing something equivalent to a white balance algorithm.

DavidMcC wrote:OK, I came to the conclusuion that crank's rediculous post above was just anotjhert attempt to get me to insult him.

Do you really believe this David?
Has it ever occured to you that your incessant need to interpet criticism of your claims as personal goading, is a problem on your part?

scott1328 wrote:
It's 6 months since Christmas and my poinsettias still have red leaves. Is this a true claim?

It's more than 6 months since you posted that, so things may have changed.

The leaves of your poinsettias still look red to you .
c.f.
I've looked at that photo of strawberries a dozen times and they still look red to me.

Do you want to say that the strawberries depicted in the photo ARE red? What would that mean? The spectrum of light tells us they are much more cyan than red (i.e. they are not red).

DavidMcC wrote:OK, I came to the conclusuion that crank's rediculous post above was just anotjhert attempt to get me to insult him. I didn't bite, just decided that this site wasn't worth bothering with, if that is all it can come up with.
A. Of course the basic kind of circuitry is the same in the fovea as elseswhere in the retina - what is different is the arbour - in the FC, it is an arnouir of one, which is how you get better quality vision in that area. I would have thought it was obvious to anyone who knows the first thing about the retina.
B. I did not claim that rods and cones are connected directly - it was you grossly misreading my posts, not me grossly misreading the standard texts on the retina!
C. The position encoding thatbI think is the exaplanation of the otherwise mysterious spike patterns is only necessary outside of the FC, because the arbour makes it possiblle (and useful) to minimize the blurring that they cause. Obviopuisly, the brain cannot tell the exact positition of each photorecptorjust fron whichg axon it is connected to when there are a hundred times as many photoreceptors as axons! Again, I thought that was obvious.

You mixed up the test system setup with the neural signaling and accuse me of ridiculous posts? You didn't manage to acknowledge that you made this serious blunder. And you fail to show a single reference that shows this positional signaling, something that seems absurd to me. I asked the simple question, why would that be needed, the info is already there by dent of which nerves the signals come in on. You fail to address that also. I hardly remember this thread now but if I get more silly accusations I will reacquaint myself with the particulars and redemolish any new BS I see.

GrahamH wrote:

scott1328 wrote:
It's 6 months since Christmas and my poinsettias still have red leaves. Is this a true claim?

It's more than 6 months since you posted that, so things may have changed.

The leaves of your poinsettias still look red to you .
c.f.
I've looked at that photo of strawberries a dozen times and they still look red to me.

Do you want to say that the strawberries depicted in the photo ARE red? What would that mean? The spectrum of light tells us they are much more cyan than red (i.e. they are not red).

Despite David's and Crank's deep dive into the minutiae of the underlying science which I quite likely accept as fun, other than it isn't quite the point of the thread.

Your post is closer to the crux of the OP. The cyan strawberries are an example of the brain/eye combination doing its thing and giving us an illusion of redness. I don't think any one is arguing against this. It in effect it is the same (similar) as the yellow circle I showed earlier ... Blue and green light combining to give an appearance of yellow. Now, some objected to the term of 'illusion' and I hope 'appearance' is a more acceptable term.

Now when an object reflects blue and green light does it mean the object itself is yellow and if an object reflects yellow does it mean it yellow? So Scott's poinsettia is red in the sense in that it appears red and by common agreement we call the poinsettia red. But is it? I don't have a clue, but it would be a coincidence if it was.

I have heard two things in this thread that vaguely ring true ... one the question is the poinsettia, itself, red? does not make sense; and by insisting that the poinsettia itself is red is a form of naïve realism.

I never realized it would be such hard concept to discuss?

What is the precise wavelength of red light?

Answer: There is no precise wavelength. Instead, WE have gauged 'red light' to have a wavelength WITHIN OUR VISIBLE SPECTRUM of between 620 - 750nm.

Question: Does this measure 'objectify' the meaning and/or value of red light?

Answer: No, since the gauge and values of 'red light' have been ascertained in the first instance from the commonality of our experiences.

In other words, it's one thing to say that 'light' has the property of having different wavelengths, but to assign numerical values to words such as 'red' (as in red light) is in itself an exercise in measuring our 'subjective' appraisal of light itself. Further, it should be noted that without this supposedly 'subjective' awareness of light, that we would have had NO knowledge of light in the first instance, not least as the basis of light having a meaning/value beyond our experience of it (as in having a wavelength beyond which we can see/experience it).

The bottom-line is that our "subjective experiences" of colour are the very essence/basis of ALL notions such as red, wavelength, and unobservable light, not least 'light' itself.

The incredible irony is that there is no means to justify the "objectivity" of the scientific understanding of light whilst simultaneously undermining the "subjectivity" of our personal experiences of it. Yet, here we are in the 21st century, all experiencing the idiotic argument that the scientific understanding of light somehow undermines the folk-psychology view of it all.

F>U>B>A>R.

In a few hundred years from now, you geezers will all be regarded in the same light as those fools who argued for the flat earth, etc.. You simply don't have a fucking clue. If I offend you by saying that, then tough shit. I'm merely here to shorten the age of this present darkness. Who knows, the odd spark might light here or there... and then the fire might spread.

GrahamH wrote:

scott1328 wrote:
It's 6 months since Christmas and my poinsettias still have red leaves. Is this a true claim?

It's more than 6 months since you posted that, so things may have changed.

The leaves of your poinsettias still look red to you .
c.f.
I've looked at that photo of strawberries a dozen times and they still look red to me.

Do you want to say that the strawberries depicted in the photo ARE red? What would that mean? The spectrum of light tells us they are much more cyan than red (i.e. they are not red).

Actually in the time since I made the claim, the poinsettias have shed those red leaves and set out new ones beginning in January.

jamest wrote:What is the precise wavelength of red light?

Answer: There is no precise wavelength. Instead, WE have gauged 'red light' to have a wavelength WITHIN OUR VISIBLE SPECTRUM of between 620 - 750nm.

A wiser James somewhere in some other universe will actually address the topic of this thread.

romansh wrote:

jamest wrote:What is the precise wavelength of red light?

Answer: There is no precise wavelength. Instead, WE have gauged 'red light' to have a wavelength WITHIN OUR VISIBLE SPECTRUM of between 620 - 750nm.

A wiser James somewhere in some other universe will actually address the topic of this thread.

But see how he reverses it. "we" have invented wavelength, photons, rods and cones etc as explanations for a primary reality of subjectivity. There's a perverse artistry about it. Or perhaps it's parody.