Imagination Can Change What We Hear and See

Imagination Can Change What We Hear and See

  1:24:00 PM    Science Lover

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A study from Karolinska Institut in Sweden shows, that our imagination may affect how we experience the world more than we perhaps think. What we imagine hearing or seeing "in our head" can change our actual perception. The study, which is published in the scientific journal Current Biology, sheds new light on a classic question in psychology and neuroscience -- about how our brains combine information from the different senses.

Illusion of colliding objects. (Credit: Image courtesy of Karolinska Institutet)

"We often think about the things we imagine and the things we perceive as being clearly dissociable," says Christopher Berger, doctoral student at the Department of Neuroscience and lead author of the study. "However, what this study shows is that our imagination of a sound or a shape changes how we perceive the world around us in the same way actually hearing that sound or seeing that shape does. Specifically, we found that what we imagine hearing can change what we actually see, and what we imagine seeing can change what we actually hear."

The study consists of a series of experiments that make use of illusions in which sensory information from one sense changes or distorts one's perception of another sense. Ninety-six healthy volunteers participated in total.

In the first experiment, participants experienced the illusion that two passing objects collided rather than passed by one-another when they imagined a sound at the moment the two objects met. In a second experiment, the participants' spatial perception of a sound was biased towards a location where they imagined seeing the brief appearance of a white circle. In the third experiment, the participants' perception of what a person was saying was changed by their imagination of a particular sound.

According to the scientists, the results of the current study may be useful in understanding the mechanisms by which the brain fails to distinguish between thought and reality in certain psychiatric disorders such as schizophrenia. Another area of use could be research on brain computer interfaces, where paralyzed individuals' imagination is used to control virtual and artificial devices.

"This is the first set of experiments to definitively establish that the sensory signals generated by one's imagination are strong enough to change one's real-world perception of a different sensory modality" says Professor Henrik Ehrsson, the principle investigator behind the study.

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Plant a New Language in Your Mind

Plant a New Language in Your Mind

  10:14:00 AM    Science Lover

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A Web app tailors language learning to your ability, and turns the experience into a game.

Vivid memories: The Chinese character for "baby" turns into a cartoon image of a baby in this visual mnemonic.
Credit: Memrise

A world memory champion and a neuroscientist have joined forces to create a language-learning website called Memrise, which combines mnemonic tricks with a game to help users learn quickly and efficiently. Its carefully paced learning structure and competitive points system, the app's developers believe, make their site more effective than other language-learning tools.

Memrise makes learning a game with virtual gardens that users must tend. As they do, they also earn points and thereby fight their way up a community-wide leaderboard.

Mandarin Chinese and English are the only languages that have been rolled out yet, but others including French, Spanish, Italian, German, and Arabic can be used in beta form. The app was recently featured at this year's Boston Techstars event, which presented startups that were chosen to receive investment.

The premise is that each word or phrase is a seed for users to plant in their gardens. A new word is planted when a user is exposed to it. Once planted, the seed sprouts in a few hours and must be harvested—that is, the user is tested, typically by having to type out words or choose characters, depending on the language. With each success, a plant is moved to a greenhouse, where it will thrive or wilt depending on how well the user tends it by practicing with the word.

"Learning should always be emotional; you should always be delighted and proud of what you've learned," says Memrise cofounder and memory champion Ed Cooke. That's where many language-learning aids lose users, he says—the presentation fails to engage users and make them want to learn.

The Memrise learning method is based on three principles. The first, Cooke says, is one of the most important aspects of memory training: vivid encoding. In order to recall otherwise arbitrary words, the user's brain benefits from connecting them to an image. The more associations to a word the user makes, the quicker and clearer the recall. Memrise provides some associations for users—the Chinese character for "man," for example, transforms into a cartoon drawing of a man. But it also encourages users to submit their own verbal mnemonics. For instance, in one French session, the phrase "une boucle" (which means "a loop" in English) is paired with a user-submitted mnemonic about a roller coaster: "I hope they boucle us in securely. This roller coaster has so many loops."



The second principle of Memrise's approach is to remind users systematically. Using an algorithm developed by neuroscientist and cofounder Greg Detre, the app is designed so "plants," or words, wilt when not tended to. The user interface tells users which plants are wilting, a problem they can remedy by "watering," or repeated testing. Reminders pop up when a user is most likely to forget new words, rather than at random intervals.

The final Memrise principle is adaptive testing, which means that questions vary in difficulty according to the user's performance. "Other language sites get this wrong," says Cooke. "It's really important that you test these memories at the right time and in the right way."

Memrise isn't the only social language-learning site on the Web. Others, like LiveMocha and Babbel, take a simpler community-based approach, in which users depend on other users for evaluation. These sites also have minor game components, offering points for achievements. But many users give up on learning a language remarkably quickly, says Cooke, and he believes that the learning techniques employed are partly to blame. "No other app uses more than one or two of these memory principles," he says, referring to the three principles behind Memrise. Most rely solely on "non-choreographed" testing, he says, and fail to encourage users to recall newly acquired words.

Memrise is currently focused on getting users to memorize words, rather than teaching a deeper understanding of a language through grammar lessons or speaking. "It seems to work relatively well for teaching vocabulary," says Luis von Ahn, a professor at Carnegie Mellon University and co-creator of a game-based language-learning website called Duolingo. "But that's only a small part of learning a language."

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Bilinguals See the World in a Different Way, Study Suggests

Bilinguals See the World in a Different Way, Study Suggests

  10:22:00 AM    Science Lover

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Learning a foreign language literally changes the way we see the world, according to new research. Panos Athanasopoulos, of Newcastle University, has found that bilingual speakers think differently to those who only use one language.

Colour perception is an ideal way of testing bilingual 
concepts because there is a huge variation between 
where different languages place boundaries on the 
colour spectrum. (Credit: iStockphoto)

 

And you don't need to be fluent in the language to feel the effects -- his research showed that it is language use, not proficiency, which makes the difference.

Working with both Japanese and English speakers, he looked at their language use and proficiency, along with the length of time they had been in the country, and matched this against how they perceived the colour blue.

Colour perception is an ideal way of testing bilingual concepts because there is a huge variation between where different languages place boundaries on the colour spectrum.

In Japanese, for example, there are additional basic terms for light blue (mizuiro) and dark blue (ao) which are not found in English.

Previous research has shown that people are more likely to rate two colours to be more similar if they belong to the same linguistic category.

"We found that people who only speak Japanese distinguished more between light and dark blue than English speakers," said Dr Athanasopoulos, whose research is published in the current edition of Bilingualism: Language and Cognition. "The degree to which Japanese-English bilinguals resembled either norm depended on which of their two languages they used more frequently."

Most people tend to focus on how to do things such as order food or use public transport when they learn another language to help them get by, but this research has shown that there is a much deeper connection going on.

"As well as learning vocabulary and grammar you're also unconsciously learning a whole new way of seeing the world," said Dr Athanasopoulos. "There's an inextricable link between language, culture and cognition.

"If you're learning language in a classroom you are trying to achieve something specific, but when you're immersed in the culture and speaking it, you're thinking in a completely different way."

He added that learning a second language gives businesses a unique insight into the people they are trading with, suggesting that EU relations could be dramatically improved if we all took the time to learn a little of each other's language rather than relying on English as the lingua-franca.

"If anyone needs to be motivated to learn a new language they should consider the international factor," he said. "The benefits you gain are not just being able to converse in their language -- it also gives you a valuable insight into their culture and how they think, which gives you a distinct business advantage.

"It can also enable you to understand your own language better and gives you the opportunity to reflect on your own culture, added Dr Athanasopoulos, who speaks both Greek and English.

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Brains Wired So We Can Better Hear Ourselves

Brains Wired So We Can Better Hear Ourselves

  8:02:00 PM    Science Lover

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Like the mute button on the TV remote control, our brains filter out unwanted noise so we can focus on what we're listening to. But when it comes to following our own speech, a new brain study from the University of California, Berkeley, shows that instead of one homogenous mute button, we have a network of volume settings that can selectively silence and amplify the sounds we make and hear.

Activity in the auditory cortex when we speak and listen 
is amplified in some regions of the brain and muted in 
others. In this image, the black line represents muting 
activity when we speak. (Credit: Courtesy 
of Adeen Flinker)

Neuroscientists from UC Berkeley, UCSF and Johns Hopkins University tracked the electrical signals emitted from the brains of hospitalized epilepsy patients. They discovered that neurons in one part of the patients' hearing mechanism were dimmed when they talked, while neurons in other parts lit up.

Their findings, published Dec. 8, 2010 in the Journal of Neuroscience, offer new clues about how we hear ourselves above the noise of our surroundings and monitor what we say. Previous studies have shown a selective auditory system in monkeys that can amplify their self-produced mating, food and danger alert calls, but until this latest study, it was not clear how the human auditory system is wired.

"We used to think that the human auditory system is mostly suppressed during speech, but we found closely knit patches of cortex with very different sensitivities to our own speech that paint a more complicated picture," said Adeen Flinker, a doctoral student in neuroscience at UC Berkeley and lead author of the study.

"We found evidence of millions of neurons firing together every time you hear a sound right next to millions of neurons ignoring external sounds but firing together every time you speak," Flinker added. "Such a mosaic of responses could play an important role in how we are able to distinguish our own speech from that of others."

While the study doesn't specifically address why humans need to track their own speech so closely, Flinker theorizes that, among other things, tracking our own speech is important for language development, monitoring what we say and adjusting to various noise environments.

"Whether it's learning a new language or talking to friends in a noisy bar, we need to hear what we say and change our speech dynamically according to our needs and environment," Flinker said.

He noted that people with schizophrenia have trouble distinguishing their own internal voices from the voices of others, suggesting that they may lack this selective auditory mechanism. The findings may be helpful in better understanding some aspects of auditory hallucinations, he said.

Moreover, with the finding of sub-regions of brain cells each tasked with a different volume control job -- and located just a few millimeters apart -- the results pave the way for a more detailed mapping of the auditory cortex to guide brain surgery.

In addition to Flinker, the study's authors are Robert Knight, director of the Helen Wills Neuroscience Institute at UC Berkeley; neurosurgeons Edward Chang, Nicholas Barbaro and neurologist Heidi Kirsch of the University of California, San Francisco; and Nathan Crone, a neurologist at Johns Hopkins University in Maryland.

The auditory cortex is a region of the brain's temporal lobe that deals with sound. In hearing, the human ear converts vibrations into electrical signals that are sent to relay stations in the brain's auditory cortex where they are refined and processed. Language is mostly processed in the left hemisphere of the brain.

In the study, researchers examined the electrical activity in the healthy brain tissue of patients who were being treated for seizures. The patients had volunteered to help out in the experiment during lulls in their treatment, as electrodes had already been implanted over their auditory cortices to track the focal points of their seizures.

Researchers instructed the patients to perform such tasks as repeating words and vowels they heard, and recorded the activity. In comparing the activity of electrical signals discharged during speaking and hearing, they found that some regions of the auditory cortex showed less activity during speech, while others showed the same or higher levels.

"This shows that our brain has a complex sensitivity to our own speech that helps us distinguish between our vocalizations and those of others, and makes sure that what we say is actually what we meant to say," Flinker said.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of Science Updates or its staff.

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Do Brain's 'Traffic Lights' Direct Our Actions?

Do Brain's 'Traffic Lights' Direct Our Actions?

  1:42:00 PM    Science Lover

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In every waking minute, we have to make decisions -- sometimes within a split second. Neuroscientists at the Bernstein Center Freiburg have now discovered a possible explanation how the brain chooses between alternative options. The key lies in extremely fast changes in the communication between single nerve cells.

The timing of exciting (red curve) and inhibiting 
(blue curve) signals could be a way to control the 
"traffic flow" of activity in the brain. (Illustration: 
Bernstein Center Freiburg) (Credit: Illustration 
courtesy of Bernstein Center Freiburg)

The traffic light changes from green to orange -- should I push down the accelerator a little bit further or rather hit the brakes? Our daily lives present a long series of decisions we have to make, and sometimes we only have a split second at our disposal. Often the problem of decision-making entails the selection of one set of brain processes over multiple others seeking access to same resources. Several mechanisms have been suggested how the brain might solve this problem. However, up to now, it is a mystery what exactly happens when during a rapid choice between two options.

In the current issue of the Journal of Neuroscience, Jens Kremkow, Arvind Kumar, and Ad Aertsen from the Bernstein Center Freiburg propose a mechanism how the brain can choose between possible actions -- already at the level of single nerve cells.

As the structure and activity of the brain are just too complex to answer this question through a simple biological experiment, the scientists constructed a network of neurons in the computer. An important aspect of the model in this context is the property of nerve cells to influence the activity of other nerve cells, either in an excitatory or inhibitory manner. In the constructed network, two groups of neurons acted as the senders of two different signals. Further downstream in the network, another group of neurons, the "gate" neurons, were to control which of the signals would be transmitted onward.

As the cells within the network were connected both with exciting and inhibiting neurons, the signals reached the gate as excitatory and, after a short delay, inhibitory activity. In their simulations, the scientists found that the key for the gate neurons' "decision" in favour of one signal over the other was the time delay of the inhibitory signal relative to the excitatory signal. If the delay was set to be very small, the activity of the cells in the gate was quenched too quickly for the signal to be propagated.

Conversely, a larger delay caused the gate to open for the signal. Results from neurophysiological experiments have already shown that a change in delay properties is possible in real neurons. These findings therefore support the hypothesis of Kremkow and colleagues that such temporal gating can form the basis for selecting one of several alternative options in our brain.

Admin's Note: This article is not intended to provide medical advice, diagnosis or treatment.

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Human Brain Can 'See' Shapes With Sound : See No Shape, Touch No Shape, Hear a Shape? New Way of 'Seeing' the World

Human Brain Can 'See' Shapes With Sound : See No Shape, Touch No Shape, Hear a Shape? New Way of 'Seeing' the World

  9:08:00 PM    Science Lover

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Scientists at The Montreal Neurological Institute and Hospital -- The Neuro, McGill University have discovered that our brains have the ability to determine the shape of an object simply by processing specially-coded sounds, without any visual or tactile input. Not only does this new research tell us about the plasticity of the brain and how it perceives the world around us, it also provides important new possibilities for aiding those who are blind or with impaired vision.

New research shows that the human brain is able to 
determine the shape of an object simply by processing 
specially-coded sounds, without any visual or tactile input. 
(Credit: iStockphoto/Sergey Chushkin)

Shape is an inherent property of objects existing in both vision and touch but not sound. Researchers at The Neuro posed the question 'can shape be represented by sound artificially?' "The fact that a property of sound such as frequency can be used to convey shape information suggests that as long as the spatial relation is coded in a systematic way, shape can be preserved and made accessible -- even if the medium via which space is coded is not spatial in its physical nature," says Jung-Kyong Kim, PhD student in Dr. Robert Zatorre's lab at The Neuro and lead investigator in the study.

In other words, similar to our ocean-dwelling dolphin cousins who use echolocation to explore their surroundings, our brains can be trained to recognize shapes represented by sound and the hope is that those with impaired vision could be trained to use this as a tool. In the study, blindfolded sighted participants were trained to recognize tactile spatial information using sounds mapped from abstract shapes. Following training, the individuals were able to match auditory input to tactually discerned shapes and showed generalization to new auditory-tactile or sound-touch pairings.

"We live in a world where we perceive objects using information available from multiple sensory inputs," says Dr. Zatorre, neuroscientist at The Neuro and co-director of the International Laboratory for Brain Music and Sound Research. "On one hand, this organization leads to unique sense-specific percepts, such as colour in vision or pitch in hearing. On the other hand our perceptual system can integrate information present across different senses and generate a unified representation of an object. We can perceive a multisensory object as a single entity because we can detect equivalent attributes or patterns across different senses." Neuroimaging studies have identified brain areas that integrate information coming from different senses -- combining input from across the senses to create a complete and comprehensive picture.

The results from The Neuro study strengthen the hypothesis that our perception of a coherent object or event ultimately occurs at an abstract level beyond the sensory input modes in which it is presented. This research provides important new insight into how our brains process the world as well as new possibilities for those with impaired senses.

The study was published in the journal Experimental Brain Research. The research was supported by grants from the Canadian Institutes of Health Research and the Natural Sciences and Engineering Research Council of Canada.

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

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Why Does a Human Baby Need a Full Year Before Starting to Walk?

Why Does a Human Baby Need a Full Year Before Starting to Walk?

  1:09:00 AM    Science Lover

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Why does a human baby need a full year before it can start walking, while a newborn foal gets up on its legs almost directly after birth? Scientist have assumed that human motor development is unique because our brain is unusually complex and because it is particularly challenging to walk on two legs. But now a research group at Lund University in Sweden has shown that human babies in fact start walking at the same stage in brain development as most other walking mammals, from small rodents to elephants.

Why does a human baby need a full year before it can start walking, while a newborn foal gets up on its legs almost directly after birth? (Credit: iStockphoto/Beth Jeppson)

The findings are published in the journal PNAS.

The Lund group consists of neurophysiologists Martin Garwicz and Maria Christensson and developmental psychologist Elia Psouni. Contrary to convention, they used conception and not birth as the starting point of motor development in their comparison between different mammals. This revealed astonishing similarities among species that diverged in evolution as much as 100 million years ago. -- Humans certainly have more brain cells and bigger brains than most other terrestrial mammalian species, but with respect to walking, brain development appears to be similar for us and other mammals. Our study demonstrates that the difference is quantitative, not qualitative, says Martin Garwicz.

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