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Sensory adaptation

Sensory adaptation refers to the way our senses adjust to different stimuli. Various senses—including hearing, touch, smell, proprioception, and sight—can adapt in response to changes in the environment. Adaptations can allow these senses to continue to function in adverse or overstimulating conditions. Created by Ronald Sahyouni.

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  • blobby green style avatar for user Jay Kim
    Are you sure the brain flips the image back over time if the goggle turns the image upside down?
    It would make more sense that brain adapted to the inverted scene and allowed proper planning of movements over time through recalibration. Please provide sources.
    (10 votes)
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    • male robot hal style avatar for user Okilus
      Taken from Wikipedia: http://en.wikipedia.org/wiki/Perceptual_adaptation#Experimental_support

      In the 1890s, psychologist George M. Stratton conducted experiments in which he tested the theory of perceptual adaptation.[2] In one experiment, he wore a reversing glasses for 21½ hours over three days, with no change in his vision. After removing the glasses, "normal vision was restored instantaneously and without any disturbance in the natural appearance or position of objects."[2]

      Modern version of inverting mirrors with harness.
      On a later experiment, Stratton wore the glasses for eight whole days. By day four, the images seen through the instrument were still upside down. However, on day five, images appeared upright until he concentrated on them; then they became inverted again. By having to concentrate on his vision to turn it upside down again, especially when he knew images were hitting his retinas in the opposite orientation as normal, Stratton deduced his brain had reprocessed his vision and adapted to the changes in vision.
      (23 votes)
  • leafers sapling style avatar for user Joshua Taylor
    At , it's mentioned that cologne is not noticed over time due to receptors in the inner ear? Is this the nose, rather?
    (11 votes)
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  • leafers ultimate style avatar for user Jerry J. Français II
    Is sensory adaptation synonymous with habituation?
    (2 votes)
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    • blobby green style avatar for user Lyolya Hovhannisyan
      The terms neural adaptation and habituation are often confused for one another. Habituation is an attentional phenomenon while neural adaptation is a physiological phenomenon, although the two are not entirely separate. During habituation, we have some conscious control over whether we notice something to which we have become habituated. However, when it comes to neural adaptation, we have no conscious control over it. For example, if we have adapted to something (like an odor or perfume), we cannot consciously force ourselves to smell that certain odor. Neural adaptation is tied very closely to stimulus intensity; as the intensity of a light increases, your senses will adapt more strongly to it.[8] In comparison habituation can vary depending on the stimulus. With a weak stimulus habituation can occur also immediately but with a strong stimulus the animal may not habituate at all[9] e.g. a cool breeze versus a fire alarm. Habituation also has a set of characteristics that must be met to be termed a habituation process.[10]
      (15 votes)
  • blobby green style avatar for user Mike Weisenhaus
    sensory adaptation that Ronald describes is in the middle ear to the stapes bone, not the inner ear. There are other adaptive mechanisms in the inner ear though.
    (7 votes)
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  • blobby green style avatar for user Tobey
    It's not really made clear at the end how exactly rods and cones lose their sensitivity to light. At first he says when the pupil constricts in the presence of bright light, "over time" rods and cones get "down-regulated," which presumably means the down-regulation with each instance of constriction is permanent. But then he says when the pupil dilates in the dark, rods and cones are "up-regulated," but ends it there, not specifying whether this also happens "over time" as the down-regulation does. So is it that the more we're in bright light, the more we're desensitized to light, but that can be counteracted by spending time in darker areas and vice versa?
    (4 votes)
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    • piceratops sapling style avatar for user Katherine Terhune
      At least part of it is because of a phenomenon called bleaching, where the pigment that detects light becomes inactivated by exposure to too much light. This is why you get blinded by bright light after coming out of a dark cave, suddenly all the pigment is bleached and must be restored before you can see again.

      Also, down-regulation and up-regulation in our bodies is very rarely permanent. It's all a dynamic process
      (5 votes)
  • starky ultimate style avatar for user ♪♫  Viola  ♫♪
    Couldn't we have up regulation in other senses too, not just vision? For example, with hearing, if you're in a quiet room, your ear becomes sensitive and picks up small noises.
    (3 votes)
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    • piceratops ultimate style avatar for user ILoveToLearn
      Yes, for sure. Actually, it rained last night, and I turned off my fan when I went to sleep. (I usually leave it blaring as loudly as it goes.) My ears picked up on every tiny little noise that I never hear because the fan is on. I not only heard the rain (which is why I turned the fan off in the first place) I could hear every tiny noise from outside, etc.
      (4 votes)
  • leafers seedling style avatar for user Aleema Yesmukanova
    At 3.15 it's said "we've talked about proprioception in earlier video". How can I find that video?
    (2 votes)
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    • purple pi purple style avatar for user Jousboxx
      Balance is a part of proprioception. If you couldn't tell which way you were oriented, walking on two legs would be extremely difficult and you would fall down often. This is just one of the many ways proprioception effects us,
      (3 votes)
  • female robot ada style avatar for user neha
    What are the so-called "light-sensitive molecules" made by the rods and cones?

    Edit: Are these the light-sensing pigments that get bleached during periods of high light exposure, causing down-regulation?
    (3 votes)
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    • marcimus purple style avatar for user melissadequadros
      I think he's referring to photo-receptors And yes, I think so. This explains how when you're coming out of a dark room into the sunlight, it's hard to adjust for a few seconds. The rods don't like bright light, and I'm thinking that there's a pathway to down-regulate the rods and switch over to the cones being activated.
      (2 votes)
  • mr pants teal style avatar for user frehman
    This video was great -- very straightforward. However, I was using some other sources to study this topic and came across a video that said habituation deals with hearing while sensory adaptation deals with touch, smell, proprioception, and sight. Khan Academy, on the other hand, says that hearing is a part of sensory adaptation. Can someone please clarify these two concepts for me. Thanks!
    (3 votes)
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  • blobby green style avatar for user aabenpoliak
    Why do you say that proprioception is down-regulated?
    (3 votes)
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Video transcript

Voiceover: In this video we're going to talk about something known as sensory adaptation. Sensory adaptation. As the name implies what sensory adaptation is is a change in the sensitivity of your perception of a sensation. We're going to look at a couple of different examples of sensory adaptation. The first example, the first sense that we're going to look at is hearing, your sense of hearing. Let's look at hearing. How is it that we're able to go to a rock concert and listen to the entire concert and walk out and still be able to hear things? How is it that our ear drums aren't blown out because of the really really loud sound? One of the ways that you're able to adapt to really loud noises is by a small muscle in your inner ear. What this inner ear muscle does is whenever there's a really loud noise it causes it to contract. When the muscle contracts it actually dampens the vibrations that go into your inner ear. By dampening really loud noises it actually helps protect your ear drums from getting blown. It helps protect your inner ear from getting damaged. This actually takes a few seconds for it to kick in. It doesn't work for really really immediate super loud noises such that of a gunshot or a rifle fire. The rife, when it goes off, the noise occurs really really quickly. The muscle doesn't have time to contract and protect your ear. You can actually have some kind of damage if you do hear a gunshot close to your ear because of this inability to contract very quickly. Another sense that we rely on heavily and that is adaptable is our sense of touch. You might've noticed that if you dip your hands in really cold water it's super cold at first, but over time the water doesn't feel as cold. That's because the sensory nerves in your hand that are sensitive to temperature, as soon as they go off, they become saturated. They stop firing as much. Your sense of touch, your sense of temperature gets adapted. Another sense that is adaptable is your sense of smell. We can detect really really low concentrations of chemicals in the air such as perfumes. I don't know if you've ever actually experienced this or not, but if you spray some cologne or some perfume on, over time at first you're able to smell it. Over time you forget that you're wearing it. That's again because the sensory receptors in your [ear], they become desensitized. They become desensitized to the molecules. Similarly, your sense of touch, the temperature receptors also get desensitized. There are a couple of other senses that also get-- that can also change and adapt to changes in stimulus. One of those changes is your sense of proprioception. This we talked about in an earlier video, but is your sense of balance, your sense of self, knowing where you are in space. One experiment they actually did to change someone's sensation of proprioception was they actually put some goggles. Imagine here we have a person. Here are his eyes. What they actually did was they put goggles on. What these goggles basically did is they skewed everything. They either made everything upside down or they titled everything at a certain angle. Basically, the perception of the world basically changed. What they were seeing was no longer what they were used to. Over time, their brain was actually able to accommodate. If an image was initially upside down, over time, the image got flipped right side up again. There's this sensory adaptation that can occur for your sense of proprioception as well. Another sense that undergoes sensory adaptation is your sense of sight. For all these senses over here we were talking about down regulation. Hearing, whenever it's a really loud sound, the muscle contracts and your ability to perceive sound is down regulated. This is the same with touch. Over time your ability to feel certain things, feel pressure, feel temperature gets down regulated. The same thing goes for smell and proprioception. With sight, we can get both down and up regulation. We can get both down and up regulation. When would we get down regulation? Imagine that it's really really bright outside. If it's super bright outside, you've got lots and lots of light coming in and it enters your eye. If your pupils were really big and dilated, let's imagine that you've got your pupils here and they're really big and dilated. A whole bunch of light would enter your pupils. In fact it could even damage your retina. One adaptation that your eyeball has to really bright intensity light is the pupil actually constricts. The pupil gets smaller. It goes from this size, for example, to this size. What that effectively does is it allows less light to enter the back of the eye. Another adaptation to bright light that occurs in your eye is the change in the sensitivity of your rods and cones. There's an entire playlist on site in which I talk about rods and cones. Basically what occurs is your rods and cones that are sitting in the [ren] in the back of your eye, they get desensitized. They actually lose sensitivity to light over time. The combination of pupil constriction and desensitization of the rods and cones in your eyes effectively leads to a down regulation in your ability to sense light. What happens in a dark setting? In a dark setting when there's not a lot of light, there's not very much light. We can just draw a little bit of light coming in. What you'd want to do is the exact opposite. If your pupils were initially small, you'd want to make them big so that we can get more light coming into the back of the eye. In addition, what happens in the dark is these rods and cones actually start synthesizing light sensitive molecules. There's actually more light sensitive molocules. They become more sensitive to light. This effectively leads to a up regulation in sensitivity.