Scientists Now Question Brain Imaging Methods
2020-12-14
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1Brain scans offer us a rare sight: A look into the mind and its mysteries.
2They promise answers to many questions.
3How do we feel pain?
4How do we know a face?
5How do we move our body?
6But can brain scans really answer these questions?
7Many scientists are now rethinking the value of brain scan research and whether its findings are true.
8Brain scan studies have been criticized for several things.
9Criticisms include using too few subjects and incorrectly reading results.
10Researchers have also come to understand that a person's brain scan results can be different from day to day, even when all the conditions stay the same.
11Now they admit that brain scan findings are limited.
12Some are studying these limitations. Others are using different methods to study the brain.
13Earlier this year, Annchen Knodt, a researcher at Duke University in North Carolina, and her team published the latest paper on this topic.
14It questioned the usefulness of common brain scan projects.
15The team looked at 60 studies of the past 10 years -- including Knodt's own studies.
16The research being re-examined uses a technique called functional magnetic resonance imaging, or fMRI.
17Using large magnets, fMRI scans find where oxygenated blood goes when someone does an activity, such as learning new words.
18This gives scientists a way to measure brain activity.
19Researchers first began using this technology in the early 1990s.
20At the time, it seemed to open a window into the human brain.
21Earlier imaging methods involved examining brain activity through small devices -- called electrodes -- placed on the skull.
22Another technique involved injecting radioactive material into the blood.
23By comparison, fMRI seemed faster and easier And the images were of higher quality.
24Scientists started writing many papers about fMRI's ability to show brain activity.
25Reporters wrote many stories about these studies.
26The public wanted more.
27But as years passed, troubling signs about some of the findings began to appear.
28"It is a very powerful thing to show a picture of the brain," said Damian Stanley, a brain scientist at Adelphi University in New York State.
29However, such a powerful tool, he said, can lead to abuse and bad science.
30Stanley told the Associated Press that some scientists made their research seem more important than it actually was.
31Another Duke brain scientist, Anita Disney, told the AP, "In the end, we probably jumped on the fMRI bandwagon a little too fast."
32In other words, the scientific community began supporting the technique very quickly, perhaps too quickly.
33But now, she said, the problems with fMRI are a concern to many scientists.
34With doubts growing, many laboratories have become more careful about which imaging methods are used in brain research.
35And when studying the brain, there is a lot to look at.
36The average brain has about 177,000 kilometers of nerve fibers.
37Yale University researcher Joy Hirsch wants to understand "the social brain."
38She studies what happens in the brain when people talk, touch, or make eye contact with each other.
39So, she does not use fMRI.
40It can only be used on one person at a time and that person must stay perfectly still inside a large scanner.
41Instead, Hirsch uses another method. Laser lights hit a fiber optic cable attached to a person's head and then finds blood flow.
42This method lets her subjects move freely during scanning.
43It also permits her to study real-life socializing among several people.
44Duke's Anita Disney also does not use fMRI very often.
45She explained that it is not accurate enough to study brain chemistry.
46But not everyone is walking away from fMRI.
47Some doctors depend on the method to map a patient's brain before an operation.
48And fMRI has proven useful for studying diseases such as schizophrenia and Alzheimer's.
49Now, there is a new imaging method.
50It is called optogenetics.
51This method uses light to activate neurons.
52It may be brain science's latest method of studying the brain.
53But some scientists say it is too early to know whether they will use it as a tool.
54Disney noted that when a new method comes out "it is actually really difficult to get people to do the basic work of understanding its limitations."
55I'm Anna Matteo.
1Brain scans offer us a rare sight: A look into the mind and its mysteries. They promise answers to many questions. How do we feel pain? How do we know a face? How do we move our body? 2But can brain scans really answer these questions? Many scientists are now rethinking the value of brain scan research and whether its findings are true. 3Brain scan studies have been criticized for several things. Criticisms include using too few subjects and incorrectly reading results. 4Researchers have also come to understand that a person's brain scan results can be different from day to day, even when all the conditions stay the same. Now they admit that brain scan findings are limited. Some are studying these limitations. Others are using different methods to study the brain. 5Earlier this year, Annchen Knodt, a researcher at Duke University in North Carolina, and her team published the latest paper on this topic. It questioned the usefulness of common brain scan projects. The team looked at 60 studies of the past 10 years -- including Knodt's own studies. 6Watching brains 'light up' 7The research being re-examined uses a technique called functional magnetic resonance imaging, or fMRI. Using large magnets, fMRI scans find where oxygenated blood goes when someone does an activity, such as learning new words. This gives scientists a way to measure brain activity. 8Researchers first began using this technology in the early 1990s. At the time, it seemed to open a window into the human brain. 9Earlier imaging methods involved examining brain activity through small devices -- called electrodes -- placed on the skull. 10Another technique involved injecting radioactive material into the blood. By comparison, fMRI seemed faster and easier And the images were of higher quality. 11Scientists started writing many papers about fMRI's ability to show brain activity. Reporters wrote many stories about these studies. The public wanted more. 12But as years passed, troubling signs about some of the findings began to appear. 13"It is a very powerful thing to show a picture of the brain," said Damian Stanley, a brain scientist at Adelphi University in New York State. However, such a powerful tool, he said, can lead to abuse and bad science. Stanley told the Associated Press that some scientists made their research seem more important than it actually was. 14Another Duke brain scientist, Anita Disney, told the AP, "In the end, we probably jumped on the fMRI bandwagon a little too fast." In other words, the scientific community began supporting the technique very quickly, perhaps too quickly. But now, she said, the problems with fMRI are a concern to many scientists. 15With doubts growing, many laboratories have become more careful about which imaging methods are used in brain research. And when studying the brain, there is a lot to look at. The average brain has about 177,000 kilometers of nerve fibers. 16Yale University researcher Joy Hirsch wants to understand "the social brain." She studies what happens in the brain when people talk, touch, or make eye contact with each other. So, she does not use fMRI. It can only be used on one person at a time and that person must stay perfectly still inside a large scanner. 17Instead, Hirsch uses another method. Laser lights hit a fiber optic cable attached to a person's head and then finds blood flow. This method lets her subjects move freely during scanning. It also permits her to study real-life socializing among several people. 18Duke's Anita Disney also does not use fMRI very often. She explained that it is not accurate enough to study brain chemistry. 19But not everyone is walking away from fMRI. 20Some doctors depend on the method to map a patient's brain before an operation. And fMRI has proven useful for studying diseases such as schizophrenia and Alzheimer's. 21Latest method for studying the brain 22Now, there is a new imaging method. It is called optogenetics. This method uses light to activate neurons. It may be brain science's latest method of studying the brain. But some scientists say it is too early to know whether they will use it as a tool. 23Disney noted that when a new method comes out "it is actually really difficult to get people to do the basic work of understanding its limitations." 24I'm Anna Matteo. 25Writers for the Associated Press reported this story. Anna Matteo adapted the story for VOA Learning English. Ashley Thompson was the editor. 26________________________________________________________________ 27Words in This Story 28scan - n. the act or process of using a special machine to see the inside of something (such as a part of the body) scan - v. to examine especially systematically with a sensing device (as a photometer or a beam of radiation) 29subject - n. a person or thing that is being dealt with in a particular way 30jump on a bandwagon - idiom to join an activity that has become very popular or to change your opinion to one that has become very popular so that you can share in its success 31neuroscientist - n. one who studies the scientific study of nerves and especially of how nerves affect learning and behavior 32nerve fiber - n. any of the processes (such as axons or dendrites) of a neuron 33fiber optic cable - n. technical : the use of thin threads of glass or plastic to carry very large amounts of information in the form of light signals 34activate - v. to cause (a device) to start working 35basic - adj. the simplest and most important parts of something (such as a subject of study)