Questions tagged [vision]

Questions regarding how the brain interprets information from the eyes. Consider using the "eyes" tag for discussion of eye anatomy, physiology and evolution.

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4
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1answer
420 views

Why do we see a different color when we mix two colors?

The compounds responsible for a color do not change when they are mixed with another material. The same compounds are there after mixing. However, when we mix colors such as blue and yellow we see ...
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2answers
2k views

How are colors outside the standard RGB color scheme perceived?

I found this image in a German book about biology. It's called DIN 5033 and represents the RGB color scheme. What colors are outside the RGB scheme, i.e., in the black areas of the picture?
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1answer
31 views

Does size correlate with sensory abilities?

On average, do smaller animals have senses inferior to those of bigger animals? I ask because it seems like a somewhat logical assumption: smaller eyes would in theory collect less light, and smaller ...
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1answer
412 views

How is color information transmitted from the eye to the brain via the optic nerve? [closed]

I would presume that is has something to do with synapses and specific chemicals starting specific charges through the optical nerve's sub-components, and that this is somehow interpreted by the brain ...
81
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3answers
14k views

Is there an RGB equivalent for smells?

Millions of colors in the visible spectrum can be generated by mixing red, green and blue - the RGB color system. Is there a basic set of smells that, when mixed, can yield all, or nearly all ...
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4answers
4k views

What are the floating translucent little objects called in the field of view? [duplicate]

Sometimes we see these small translucent shapes moving by when the eyes are open. When the eyes are moved they seem to follow that movement, but with a certain delay, as if they are floating in a ...
-1
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1answer
326 views

How do humans know what goes on in optical illusions? [closed]

Optical illusions are designed to deceive humans, I think. That thing is moving! It really is! It's moving! However, user Konrad Rudolph just told me what went on in a different optical illusions ...
4
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2answers
353 views

Is brain plasticity such that we can train ourself to see with our ears?

I am finishing writing some code which will parse a photo (eventually video) and use all the RGB information to synthesize an audio representation. I am wondering whether a typical person has ...
3
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1answer
1k views

What is the essential benefit of center-surround organization of retinal ganglion cells?

I am trying to understand the significance of the overlapping on-center off-surround and off-center on-surround organization of the retinal ganglion cells, also called center-surround organization. ...
8
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5answers
1k views

What is the smallest difference in light wavelength that the human eye can detect?

Is there a lower limit to the difference in wavelength (colour) our eyes can detect? If so, is this consistent between individuals? Are there any other traits correlated with precise colour vision?
3
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0answers
2k views

Why does double vision when drinking happen?

Why do you see double sometimes when you're drunk? Its weird because it seems to happen more when you try to focus. Try to look at something when you're drinking and it barely seems to double up Try ...
3
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1answer
87 views

Photoreceptors and light with mixed frequencies

I am interested in how the activation of a, say, blue cone depends on the incident light. Wikipedia tells me this: , which describes how strong the activation of the blue cone is for light with a ...
3
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1answer
3k views

What is the connectivity between on-center & off-center bipolar cells?

Do rod-photoreceptors only form synapses with on-center bipolar cells (and on-center ganglion cells in the next step)? If so, why is that? Why do rod-cells only connect to on-center cells, while the ...
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0answers
223 views

Can human eys/the brain be trained to see with bidirectional monocular vision?

Most people have a dominant eye, and while it uses its non-dominant eye in tandem with the dominant eye most of the time, the brain, being an expert in eliminating redunant information, ignores the ...
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1answer
2k views

Does light from the left visual field reach the temporal left retina?

A diagram of the visual pathway is shown here. Light from the left visual field reaches the left nasal retina and the right temporal retina. On the other hand light from the right visual field reaches ...
11
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1answer
3k views

Can “red” cone cells actually see much red light?

In electronics, the most common color scheme is the "red-green-blue" (RGB) scheme. This choice is often justified by claiming that the long- (L), medium- (M), and short- (S) type cones in the human ...
6
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1answer
599 views

What do blue cone cells add to visual function?

First of all, I saw this other question in the SE sites with a good answer, but I didn't find an explanation about the blue cones specifically. So most human beings have 3 types of cones (cells ...
0
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0answers
644 views

Is there any functional difference between Occipital lobe ( in mammals) and Optic lobe (vertebrates other than mammals)?

Visual processing centre in mammals and lower-vertebrates, are known to be different. In mammals, such as human, it is the Occipital Lobe of 2 hemispheres of cerebral cortex; which is a part of ...
3
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1answer
222 views

What happens when the congenitally blind brain receives visual input?

If a congenital blind person gets eye sight (either hypothetically, or in the near future due to advancements in technology), will their brain be able to handle that information, or will it become ...
5
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1answer
3k views

Why can myopic eyes focus on nearby objects, but not on distant ones?

In myopic eyes, far away objects get blurry. I understand that myopia means that the focus of the lenses concentrates light at a point in front of the retina, thus by the point the light rays reach my ...
3
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1answer
174 views

Nature of sight/ color perception?

I am wondering how we perceive color and whether that is dependent on the wavelength of the light, or on something manufactured in the brain. For instance, if we evolved on a planet orbiting a red ...
4
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1answer
58 views

Do low light levels during development affect the distribution of rods and cones in the retina?

I just can't seem to find any retinal development experiments that have been done using low light conditions. I am very interested in knowing if raising an animal in such conditions leads to a ...
5
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1answer
2k views

Can a color-blind person see color with filter glasses?

Why does color vision improve in color-blind persons using these filter glasses from Enchroma? Will a color blind person be able to see the same colors on a television? I'm asking, because the colors ...
12
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1answer
314 views

What really is color and how do we perceive it?

How do our brains actually transform the information that the cones in our eyes receive into the different colors that we can see and imagine?
9
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1answer
6k views

Why does my eyes see a red spot when over exposed to light?

When I looked into my projector when it was on the blue screen it left a red spot in my vision. I should not have tried it but all the colors left a red spot. Why not a blue or yellow spot was left?
4
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1answer
336 views

Do blind birds bob their head when they walk?

Birds try to keep their heads still for short periods of time between steps to improve their ability to see. You can find amusing videos of chickens used as small video camera stabilizers. But does ...
2
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1answer
591 views

Relaxing Eyes when using Virtual-Reality-Glasses?

Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies (eye focusing). For distant vision, the ciliary ...
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0answers
49 views

Does the change in eye color (melanin concentration) affect the iris pattern?

In cases of acquired heterochromia, is there a quantifiable change in the iris pattern; the clefts , furrows, etc. If yes, what changes are observed? And if no, are there any diseases or acquired ...
15
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1answer
7k views

Why do we go blind for a few seconds after switching off the light?

At night, when I switch off the lights, I always seem to go blind for a while. The room becomes pitch black and I am unable to see anything. After a while, however, my vision slowly recovers and I ...
2
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0answers
44 views

Controlling the pursuit path of the human eye

The human eye scans images by panning focus along a certain path. Stork et al. (2002) revealed that there is a feedback process involved in moving ocular focus along a path that produces minimum ...
64
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2answers
21k views

What is the evolutionary advantage of red-green color blindness?

Red-green colorblindness seems to make it harder for a hunter-gatherer to see whether a fruit is ripe and thus worth picking. Is there a reason why selection hasn't completely removed red-green ...
29
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2answers
8k views

Is it possible that by mutation a human could see infrared or other 'colours'?

Incoming light reacts with the several types of cone cells in the eye. In humans, there are three types of cones sensitive to three different spectra, resulting in trichromatic color vision. Each ...
3
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1answer
208 views

Do primate RGCs have overlapping receptive fields?

According to this link, http://hubel.med.harvard.edu/book/b10.htm retinal ganglion cells (RGCs) receive input from overlapping receptive fields (RFs). This is also an idea used in convolutional ...
25
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7answers
7k views

Why can't we see in low light if staring long enough?

For me it seems reasonable that if I kept my gaze on a fixed point in a room with low light, a progressively brighter and better picture would appear before my eyes, just like a camera can see in the ...
3
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1answer
637 views

What determines the shape of the center-surround receptive fields of retinal ganglion cells?

The wikipedia article about receptive fields of visual system tells us the following: The receptive field is often identified as the region of the retina where the action of light alters the firing ...
22
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3answers
54k views

Why do I see different hues of colors between each of my eyes?

Frequently, I see colors with a slightly different hue when looking through my eyes individually. The right eye is more red-tinted ('warmer' hued) and the left is typically more blue-tinted ('cooler' ...
10
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1answer
1k views

Are 2 eyes necessary for 3D vision?

To start off: I'm not a biology student, but a computer science major It has always been my understanding that humans have 2 eyes so that we can have 3D vision: the left eye see more of the left side ...
2
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1answer
2k views

Why is it necessary to have both cone and rod cells in the eye?

Our eyes have both cone and rod cells. Rod cells measure the intensity of light whereas cone cells identify the colour of the image formed in the eyes. So cone cells must also be able to identify ...
6
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1answer
324 views

Perception of white in the absence of rods

If the retina would not have any cones, one would be color blind. If white is the presence of all colors (in the matter of color mixture, not addition), then what would white look like without rods?
4
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1answer
23k views

Are there animals / mammals which only have one eye?

Do all animals (of a certain size and not thinking about worms) have the possibility to perceive depth? Do all mammals have at least two eyes? Are there mammals with more than two eyes?
22
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1answer
2k views

Why can't I read everything in my field of view?

When I look at a piece of text, I can see all the text on the paper, no matter where I look, because my field of view covers it all. However, if I stare at a specific word, I cannot read the text a ...
7
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1answer
2k views

Colorblindness in females and random X chromosome inactivation

From Annenberg Learner: Because the X is inactivated randomly in cells, one cell could have the maternal X inactivated, while the adjacent cell could have the paternal X inactivated. This causes ...
10
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2answers
5k views

Why can't our eyes smoothly transition from side to side without focusing on a moving object?

Why are we not able to slowly and smoothly look from side to side, or up and down in a single and smooth transition, given that we are able to do this if our eyes are focused on a moving object?
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2answers
745 views

Is there a difference between visual sensation and imagination in the brain?

How substantial is the difference between the neural signal associated with seeing an image and the imagination of that image? Surely, it can not entirely copy the pathway from the sensory organs to ...
7
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1answer
2k views

What is the function of the human eye white?

If you have a look at the eyes of most animals, you never see the white part unless the eyes are averted. In contrast, humans always have the whites visible because the iris is quite small. The only ...
9
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2answers
2k views

How many mega pixels does the eye have?

What is the number of mega pixels available in the human eye? It seems that newer camera models continuously keep increasing their pixel count. However, they never seem to be capable of reproducing ...
4
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1answer
410 views

Why doesn't the ambient lighting condition change the perception of colors we see on a monitor?

Suppose that I take a picture of an object illuminated by an incandescent light bulb and I choose the daylight white balance setting. The picture I then get will display a white object as looking ...
4
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2answers
5k views

How can some animals see ultraviolet or infrared light?

I know that some animals like birds, bees, and fish can see ultraviolet and infrared light. Whether it to detect flowers that bare nectar, or the urine trails of prey. But what I don't understand is ...
2
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1answer
928 views

All-trans-retinal being converted back to 11-cis-retinal or vitamin A

There are two pathways all-trans-retinal can take after detaching from the scotopsin: (1) it can convert back to 11-cis-retinal, or (2) it can convert to all-trans-retinol (form of vitamin A), which ...
2
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1answer
2k views

What causes the bright flash of light when poking my eye?

Recently, I poked myself in between my eye and eye socket, right below my eyebrow, and sometimes I would get this flash of light. Others have tried this too, and they also had a flash of light. I am ...