Jun 23, 2020 01:13 AM
(This post was last modified: Jun 23, 2020 01:14 AM by C C.)
https://www.livescience.com/nueroscience...mbers.html
EXCERPTS: A man held up a big foam number "8" on its side like an infinity sign and said the object, with its two loops, looked like a mask to him. But when he turned the foam number upright, the object dematerialized into a jumble of lines. "He described it as being the strangest thing he's ever seen," said David Rothlein, a postdoctoral researcher and cognitive scientist [...] This man, referred to by his initials RFS, has a rare degenerative brain condition that does not allow him to "see" numbers — on paper, as objects or even those secretly embedded in scenes.
There are exceptions: While the numbers 2 through 9 look like a scramble of meaningless curves to him, he has no problem seeing the number "0" and the number "1," according to a new case report on which Rothlein is a co-author. RFS' case is more evidence that even in healthy brains, we aren't always aware of what we see.
[...] RFS is the first patient with an inability to see numbers. "He sees something … a scramble of lines and he calls it spaghetti," Michael McCloskey said [senior author, cognitive scientist]. RFS knows that what he's seeing is a number — though he doesn't know which number — just because he doesn't see this series of nonsense lines for anything else.
And he can't memorize the different orientations of lines and assign a number to them, because they change every time he looks away and looks back, McCloskey said. "What is most striking though is that it affects the numbers and not other symbols," he told Live Science. Symbols or letters may look similar to numbers; a capital B, for example, looks like an 8. But he has no problem seeing letters or other characters.
This means that his brain has to determine that these digits he's looking at are in their own special category (aka they are numbers) in order for his comprehension of them to be scrambled, McCloskey said. But the question then is: If he can't see them, how does he do that? It's also "surprising" that his brain doesn't have problems with "0" and "1," McCloskey added. It's not clear why, but those two numbers might look similar to letters like "O" or "lowercase l," he said. Or those two numbers might be processed differently than other numbers in the brain, as "zero wasn't invented for quite a long time after the other digits were," he said.
[...] So it seems "you can do an awful lot of work in the brain to know what it is you're looking at without any awareness resulting from that," McCloskey said. The processing of numbers "is happening very normally," in RFS' brain, McCloskey said. When you're looking at stuff, that signal comes in from the eyes but then the brain does a lot of work to figure out what that shape is and how it's separate from other things you're simultaneously looking at. RFS' brain knows that he's looking at the number 8, for instance, but doesn't let him become aware of that knowledge.
"We think RFS' brain is just like everybody else's except that his disease has damaged ... something … that has to happen for awareness," McCloskey said. "He does the brain work to determine what he's looking at, but then the additional work to be aware of it is going wrong."
Once the brain has determined what you're looking at, one of two things may cause awareness, and it's an ongoing debate in the field of neuroscience, he said. The brain might either send signals to an area involved in higher-processing tasks such as analyzing and identifying what you're looking it or it may send signals back down to areas of the brain involved in lower-processing functions where just the basics of the figure, such as its shape, is analyzed, McCloskey said. "Whichever of these it is, that's where things are going wrong with RFS," McCloskey said.
[...] Semantic memory is a set of ideas and concepts that we don't draw from personal experience, but are rather common knowledge such as the sound of letters. So it's likely that RFS' inability to see numbers may stem from trouble integrating language and vision, "possibly tapping into some accessing of semantic knowledge," Rottman told Live Science in an email. "They've done a good job in finding a very specific deficit," and their interpretations of this integration are "very reasonable," he added.
The group of researchers created new digits for RFS which they called "surrogate digits" so that he could use them in daily life. [...] The researchers created a new set of numbers for him to work with, which he could see fine. This scrambling likely "only happens for digits in their usual form because recognizing those digits involves different brain areas than recognizing numbers in different forms," such as words or surrogate digits, McCloskey said.
RFS was an engineer and worked as an engineer for several years after this problem with digits arose, Rothlein said. "He is perfectly capable at number processing, so if you asked him to do arithmetic using number words or even Roman numerals he can do math just fine," he said. "In fact, he's quite good at math." (MORE - details)
EXCERPTS: A man held up a big foam number "8" on its side like an infinity sign and said the object, with its two loops, looked like a mask to him. But when he turned the foam number upright, the object dematerialized into a jumble of lines. "He described it as being the strangest thing he's ever seen," said David Rothlein, a postdoctoral researcher and cognitive scientist [...] This man, referred to by his initials RFS, has a rare degenerative brain condition that does not allow him to "see" numbers — on paper, as objects or even those secretly embedded in scenes.
There are exceptions: While the numbers 2 through 9 look like a scramble of meaningless curves to him, he has no problem seeing the number "0" and the number "1," according to a new case report on which Rothlein is a co-author. RFS' case is more evidence that even in healthy brains, we aren't always aware of what we see.
[...] RFS is the first patient with an inability to see numbers. "He sees something … a scramble of lines and he calls it spaghetti," Michael McCloskey said [senior author, cognitive scientist]. RFS knows that what he's seeing is a number — though he doesn't know which number — just because he doesn't see this series of nonsense lines for anything else.
And he can't memorize the different orientations of lines and assign a number to them, because they change every time he looks away and looks back, McCloskey said. "What is most striking though is that it affects the numbers and not other symbols," he told Live Science. Symbols or letters may look similar to numbers; a capital B, for example, looks like an 8. But he has no problem seeing letters or other characters.
This means that his brain has to determine that these digits he's looking at are in their own special category (aka they are numbers) in order for his comprehension of them to be scrambled, McCloskey said. But the question then is: If he can't see them, how does he do that? It's also "surprising" that his brain doesn't have problems with "0" and "1," McCloskey added. It's not clear why, but those two numbers might look similar to letters like "O" or "lowercase l," he said. Or those two numbers might be processed differently than other numbers in the brain, as "zero wasn't invented for quite a long time after the other digits were," he said.
[...] So it seems "you can do an awful lot of work in the brain to know what it is you're looking at without any awareness resulting from that," McCloskey said. The processing of numbers "is happening very normally," in RFS' brain, McCloskey said. When you're looking at stuff, that signal comes in from the eyes but then the brain does a lot of work to figure out what that shape is and how it's separate from other things you're simultaneously looking at. RFS' brain knows that he's looking at the number 8, for instance, but doesn't let him become aware of that knowledge.
"We think RFS' brain is just like everybody else's except that his disease has damaged ... something … that has to happen for awareness," McCloskey said. "He does the brain work to determine what he's looking at, but then the additional work to be aware of it is going wrong."
Once the brain has determined what you're looking at, one of two things may cause awareness, and it's an ongoing debate in the field of neuroscience, he said. The brain might either send signals to an area involved in higher-processing tasks such as analyzing and identifying what you're looking it or it may send signals back down to areas of the brain involved in lower-processing functions where just the basics of the figure, such as its shape, is analyzed, McCloskey said. "Whichever of these it is, that's where things are going wrong with RFS," McCloskey said.
[...] Semantic memory is a set of ideas and concepts that we don't draw from personal experience, but are rather common knowledge such as the sound of letters. So it's likely that RFS' inability to see numbers may stem from trouble integrating language and vision, "possibly tapping into some accessing of semantic knowledge," Rottman told Live Science in an email. "They've done a good job in finding a very specific deficit," and their interpretations of this integration are "very reasonable," he added.
The group of researchers created new digits for RFS which they called "surrogate digits" so that he could use them in daily life. [...] The researchers created a new set of numbers for him to work with, which he could see fine. This scrambling likely "only happens for digits in their usual form because recognizing those digits involves different brain areas than recognizing numbers in different forms," such as words or surrogate digits, McCloskey said.
RFS was an engineer and worked as an engineer for several years after this problem with digits arose, Rothlein said. "He is perfectly capable at number processing, so if you asked him to do arithmetic using number words or even Roman numerals he can do math just fine," he said. "In fact, he's quite good at math." (MORE - details)
