They once were blind but now they see. Which begs the question — what exactly do people see when they gain sight for the first time? Often, it’s terrifying.
What happens when people first really look at the world? Generally, we don’t know. They’re far too young to tell us what’s going on in their mind. By the time children are old enough to articulate what they see, they don’t remember what the world looked like in their first few weeks of life. There are special occasions, though, when full-grown adults can see for the first time. For the most part, they see a complete confusion. Often, that does a lot of emotional damage.
One of the earliest-known cases of regained sight is Virgil, the Roman poet. At age fifty, he had cataract surgery and regained his sight. Soon after, he wished he hadn’t. This is common to many blind people who regain their sight. Unlike infants, who are catered to, whose brains are primed for learning, and who have no option but to learn, blind people are asked to replace a familiar sensory system that reliably guides them through the world with an unfamiliar one that does nothing but confuse them. Sometimes the strain of assimilation is too much. Like many other patients, Virgil would shut his eyes and pretend he was still blind when the situation became overwhelming. He became depressed and died of pneumonia soon after his surgery. Although he had seen the world with his eyes, he retained his “mental blindness,” or what experts call “visual agnosia.”
For someone to see an object, the eye needs to pick it up, but the brain also needs to recognize it. This process takes both practice and a certain physical ability in the brain. Agnosia patients have generally suffered brain injuries and lost the ability to understand what they see – they see a rectangular object with a brown circle on top and a loop on one side, but don’t understand that they’re looking at a cup of coffee. There are only shapes. Those who have been blind most of their lives “wake up” with a certain amount of visual agnosia.
Spatial distance is often the primary problem they run into. One man saw people walking away from him as inexplicably shrinking. Another would practice spatial recognition by going out in a field and throwing his boot as far as he could. He’d hold out his hand to grab it, and if it wasn’t in reach, step forward before trying again.
Another area that many newly-sighted people find inexplicable is paintings and other visual representations. They can comprehend real objects, but not painted ones. When they do understand what the paintings are meant to represent, the shadows that are meant to define space and give shape just look like dark marks on the painting. Which, technically they are. It’s only a willful visual laziness on the part of the sighted that lets us see these paint blotches as shadows rather than shapes and colors.
Because we develop familiarity with faces and facial expressions at specific times in our lives – those who are deprived of human contact or changing facial expressions at that age often have trouble reading expressions for their entire lives – formerly blind people are often face-blind, or unable to decipher emotion from facial expression. Some have trouble differentiating between male and female faces.
Which isn’t to say that these people always have a completely blank slate, visually-speaking. It’s been shown that when blind people read Braille the visual cortex activates. They “see” with their brains, just not with their eyes. Surgeries on children are particularly successful. One doctor was surprised to find that a ten year old was coordinated enough to catch paper balls thrown at him only a few weeks after surgery, and knew the medical staff by sight. Young people assimilate the world very quickly.
In one famous case, a man regained his sight after being functionally blind since the age of ten months. (He was able to point at bright objects, but nothing more.) He had worked with machines and mechanics, and was able to read the clock in his hospital room shortly after recovering from surgery. The shapes, however unfamiliar to his eyes, made sense to his brain. He was also able to find his way around the room, coordinating what he saw with distances that he had walked before surgery.
When psychologists asked him to draw what he saw, starting with people, his house, and a bus,his drawings were quite extraordinary. They began as simple shapes. Houses were perfect squares with square windows and a rectangular door - the way a small child would draw a house. His buses were similar, squares and circles. As he developed, he added more detail to the design of the bus, including the text on its signs, but forgot to add parts of the outline of the bus, so that windows and wheels appear to be floating. He can draw people, in a symbolic way - two arms, two legs, and a head with all the features. When asked to draw an elephant he drew a smeared gray shape with four legs and tubes for both head and tail. Once he couldn’t represent the object with shapes or features that he knew had to be there, he couldn’t recreate it.
Learning to see is, in many ways, like learning to read. It’s a complex process involving time, practice, and mental ability, but it’s a process that only works one way. At some point we lose the ability to look at a “stop” sign and not automatically read the word “stop” – but at least not understanding the written word is imaginable. The idea of not understanding that a stop sign is a sign, or that it is a solid object placed in front of one thing and behind another, reaches too far back into our history. We have to look at others to understand what the world looks like before we connect “looks” to the world.
Amazing. What with all the recent technology that has come out to give the blind the ability of sight, I hadn’t even considered such advances to be detrimental on quality of life for recipients. After learning about blind sight and spatial neglect though, this makes a lot of sense. Guess it just goes to show that technological advancements aren’t always good news if the big picture isn’t taken into account…
The chemical formulas of various substances used to mimic plant-based aromas and flavors.
Tastes like science.
Careful of that isopentylacetate (natural chemical in ripe bananas), it’s also used as a chemical alarm signal when bee’s sting predators to attract other bees. Hence, eat bananas far from bee hives :P
Today I found out that sugar can act to modulate opiod receptor activity, or in other words, change the way your body perceives pain; wow. In the conversation of the rising rate of obesity and related metabolic diseases, I find this a real eye opener. Sugar addiction is a real problem that many industries profit off of. To think, something as simple as a sugary snack could lead to self medication for depression and anxiety is mind blowing. In other news, i’m gonna down some more fruit…
Federal officials say a large study of premature infants was ethically flawed because doctors didn’t inform the babies’ parents about increased risks of blindness, brain damage and death.
The study involved more than 1,300 severely premature infants at nearly two dozen medical institutions between 2004 and 2009. The infants were randomly assigned to receive two different levels of oxygen to see which was better at preventing blindness without increasing the risk of neurological damage or death.
In a March 7 letter, a Department of Health and Human Services official told the researchers that the study “was in violation of the regulatory requirements for informed consent” because parents weren’t told in advance about the “reasonably foreseeable risks.”
In fact, the consent form signed by parents “did not identify any risks” from subjecting the infants to either the low or high levels of oxygen used in the study,” writes Lisa Buchanan of the Office for Human Research Protections, part of HHS.
The study, published in 2010 by the New England Journal of Medicine, showed that infants who got the higher level of oxygen had more than twice the incidence of severe blindness, while infants who got the lower level were slightly more likely to die.
Among the 654 babies in the low-oxygen group, 130 died — 3.2 percent more than in the high-oxygen group.
In the high-oxygen group, 91 of 509 developed blindness — a rate of nearly 18 percent, compared to 9 percent in the low-oxygen group.
The study was designed to address a long-standing problem in the care of very premature babies. It’s known that if they get too much oxygen, that can cause blindness from a condition called retinopathy of prematurity. But if they don’t get enough, they can suffer brain damage and death.
About 500 infants a year become legally blind from this condition, out of about 28,000 US infants born every year weighing less than 2 3/4 pounds.
The feds’ letter was addressed to Richard Marchase, an executive at the University of Alabama at Birmingham, a lead institution in the multicenter study.
Marchase says, in an interview withThe New York Times, that the death rate of infants in the low-oxygen group was actually lower than a similar group of infants born around the same time who weren’t in the study.
He also maintains that all the infants in the study were given enough oxygen to keep their blood levels within the standard range.
But the HHS letter takes issue with that contention. The study was designed, it said, to give infants in the high-oxygen group “more oxygen than average infants receiving standard care, and infants assigned to the lower range received less.”
Marchase seems to acknowledge that the study’s informed consent language could have been better. In the future, he tells the Times, “We will to the best of our ability let the subjects or their parents know as thoroughly as possible what previous studies suggest in terms of risk. We are going to be very sensitive to that going forward….”
The flawed consent forms were approved by ethics committees at all 23 medical centers involved in the study. They included such prestigious institutions as Stanford, Yale, Duke, Tufts and the University of California, San Diego.
The ethical problem came to light because a consumer group called Public Citizen called on HHS Secretary Kathleen Sebelius to apologize to the parents of the 1,316 infants who agreed to participate in the study.
“The word ‘unethical’ doesn’t even begin to describe the egregious and shocking deficiencies in the informed-consent process for this study,” Dr. Michael Carome of Public Citizen’s Health Research Group says in a press release. He says it’s likely that many parents would not have agreed to enroll their infants in the study if they had known about the risks.
Carome formerly worked for the HHS Office of Human Research Protections.
In addition to an apology from Sebelius, Public Citizen calls on HHS to investigate “how the HHS system for review and oversight of clinical trials failed so miserably.”
I’ve been taking an ethics class at school for a GE that’s heightened my sensitivity to everyday ethical conflicts. As a woman of science, the search to find information in the hopes of helping many is incredibly appealing but ethical dilemmas like this highlight how important it is to thoroughly evaluate a situation with such strong influence over the lives of others.
The eyes sometimes have it, beating out the tongue, nose and brain in the emotional and biochemical balloting that determines the taste and allure of food, a scientist said here today. Speaking at the 245th National Meeting & Exposition of the American Chemical Society (ACS), the world’s largest…
After learning about ventral vs dorsal emotional processing in class, this sounds extremely interesting. I never knew much about how connected the emotional regions of the brain and our visceral senses were. That orbitofrontal cortex is looking more and more interesting the more I read :p
Say hello to the stunning results of CLARITY — a new technique that enables scientists to turn brain matter and other tissues completely transparent. It’s already being hailed as one of the most important advances for neuroanatomy in decades, and it’s not hard to see why.
Cut off a mouse’s head. Carefully remove its brain, wash it gently, and you’ll wind up with something resembling the sample pictured above, on the left. Grey matter, it so happens, lives up to its name. Due in large part to molecules known as lipids, organs like the brain are usually opaque. Lipids comprise cell membranes and provide structural support to a variety of organs and tissues throughout the body – but they also scatter light. As a result, most microscopes are lucky if they can peer even a millimeter into biological matter before images in the viewfinder get blurry.
One of the more popular techniques scientists use to get around this hangup is called “sectioning.” It’s brutally straightforward in practice: a researcher will freeze a chunk of tissue (a mouse brain, for example) in liquid nitrogen, and then slice it into scores of little sheets, each one just a fraction of a millimeter thick. This turns a single 3-dimensional problem (otherwise inscrutable, due to its non-transparent nature) into a series of 2-dimensional ones. Go through a brain layer by layer, and you can cobble together a volumetric picture of everything from cellular structure, to the spatial distribution of proteins, to the various connections that form between neurons. But the tradeoff is substantial. You’re literally cutting your sample into a bunch of tiny little pieces. With every slice, tissue is deformed, connections are severed, information is lost.
CLARITY does away with the slicing and dicing entirely. The technique, described in the latest issue of Nature by a team led by Stanford researchers Kwanghun Chung and Karl Deisseroth, works by stripping away all of a tissue’s light-scattering lipids, while leaving everything else right where it belongs. You’ll recall, however, that lipids play an important structural role in organs like the brain; if you remove them, everything else falls apart — a fact that has plagued past attempts at making tissues see-through. But that’s where CLARITY is different.
CLARITY works by virtue of a bait and switch. In their study, Chung and Deisseroth submerge a mouse brain in a mixture of formaldehyde and acrylamide. The former attaches important cellular structures and components to the latter, which solidifies into a gel when heated. An electrical current is then coursed through the gel, stripping it of anything not hanging on. The lipids go bye-bye, and the brain goes clear as Jell-O. More importantly: all of its significant structures remain intact and in place. Neurons, synapses, proteins, DNA. Every last component is exactly where it should be.
The ability to strip a brain of its lipids and nothing else gives rise to remarkable research possibilities. In the image above, a mouse brain turned transparent with CLARITY has been made visible again by labeling specific neurons with a fluorescent marker that glows green. Researchers have been using this technique (called “immunolabeling”) to highlight certain molecular and structural features for years, but with CLARITY, labeled cells can be seen in three dimensions, all at once.
In fact, the process of removing the brain’s lipids actually makes the tissues more permeable, making it easier to not only tag them with fluorescent markers in the first place, but untagthem and then tag them again with an entirely different label. What’s more, the fact that you don’t have to cut a brain up to see how it was stained means that you can add more tags to the same brain. The picture below shows a region of the brain known as the hippocampus that has had its different neurons labeled in a variety of fluorescent colors. A brain that was once impermeable to light has been made invisible, only to be made visible again – but this time with remarkable specificity.
There’s nothing that says this technique couldn’t be used on human brains, so long as you have the time. Coloring-in a clarified brain like the one above requires soaking it in solution with the fluorescent labels you want to tag it with. For a mouse brain, that can take a month or more. For a brain as voluminous as a human’s, it would take much longer. (While Chung and Deisseroth did demonstrate their technique could be used on human brains, they did so with a small block of tissue, not an entire brain.)
Likewise, there’s nothing that says CLARITY could not be used on tissues besides the brain, though the organ certainly shows the most immediate promise. The ability to visualize the neuronal connections throughout a transparent brain, for example, could spur incredible growth in the field of connectomics, which seeks to map the brain’s neuronal wiring. In neuroscience, few tools are as coveted as those that enable you to see the part and the whole simultaneously – CLARITY could enable researchers to study the structure and distribution of individual neurons in the context of the whole brain. “This is the kind of innovation that will slingshot neuroscience far beyond today,” said Henry Markram, leader of Europe’s recently unveiled Human Brain Project, in an interview with NatGeo’s Ed Yong. “This new method of whole-brain imaging across all levels of the brain provides a way to acquire much of the key data we will need.”