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Scooped by Dr. Stefan Gruenwald!

Seeing sound: visual cortex processes auditory information too

Seeing sound: visual cortex processes auditory information too | Amazing Science |

Ten healthy subjects wearing blindfolds were given solely auditory stimulation in the absence of visual stimulation. In a separate session, retinotopic mapping.

University of Glasgow scientists studying brain process involved in sight have discovered that the visual cortex also uses information gleaned from the ears when viewing the world.

They suggest this auditory input enables the visual system to predict incoming information and could confer a survival advantage.

“Sounds create visual imagery, mental images, and automatic projections,” said Professor Lars Muckli, of the University of Glasgow’s Institute of Neuroscience and Psychology, who led the research. “For example, if you are in a street and you hear the sound of an approaching motorbike, you expect to see a motorbike coming around the corner.”

The study, published in the journal Current Biology (open access), involved conducting five different experiments using functional Magnetic Resonance Imaging (fMRI) to examine the activity in the early visual cortex in 10 volunteer subjects.

In one experiment they asked the blindfolded volunteers to listen to three different sounds: birdsong, traffic noise and a talking crowd. Using a special algorithm that can identify unique patterns in brain activity, the researchers were able to discriminate between the different sounds being processed in early visual cortex activity.

A second experiment revealed that even imagined images, in the absence of both sight and sound, evoked activity in the early visual cortex.

“This research enhances our basic understanding of how interconnected different regions of the brain are,” Muckli said. “The early visual cortex hasn’t previously been known to process auditory information, and while there is some anatomical evidence of interconnectedness in monkeys, our study is the first to clearly show a relationship in humans.

“This might provide insights into mental health conditions such as schizophrenia or autism and help us understand how sensory perceptions differ in these individuals.”

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Illuminating neuron activity in 3-D: New technique lets scientists monitor small worm's entire nervous system

Illuminating neuron activity in 3-D: New technique lets scientists monitor small worm's entire nervous system | Amazing Science |

Researchers at MIT and the University of Vienna have created an imaging system that reveals neural activity throughout the brains of living animals. This technique, the first that can generate 3-D movies of entire brains at the millisecond timescale, could help scientists discover how neuronal networks process sensory information and generate behavior.

The team used the new system to simultaneously image the activity of every neuron in the worm Caenorhabditis elegans, as well as the entire brain of a zebrafish larva, offering a more complete picture of nervous system activity than has been previously possible.

“Looking at the activity of just one neuron in the brain doesn’t tell you how that information is being computed; for that, you need to know what upstream neurons are doing. And to understand what the activity of a given neuron means, you have to be able to see what downstream neurons are doing,” says Ed Boyden, an associate professor of biological engineering and brain and cognitive sciences at MIT and one of the leaders of the research team. “In short, if you want to understand how information is being integrated from sensation all the way to action, you have to see the entire brain.”

The new approach, described May 18 in Nature Methods, could also help neuroscientists learn more about the biological basis of brain disorders. “We don’t really know, for any brain disorder, the exact set of cells involved,” Boyden says. “The ability to survey activity throughout a nervous system may help pinpoint the cells or networks that are involved with a brain disorder, leading to new ideas for therapies.”

Scanning the brain with a laser beam can produce 3-D images of neural activity, but it takes a long time to capture an image because each point must be scanned individually. The MIT team wanted to achieve similar 3-D imaging but accelerate the process so they could see neuronal firing, which takes only milliseconds, as it occurs.

The new method is based on a widely used technology known as light-field imaging, which creates 3-D images by measuring the angles of incoming rays of light. Ramesh Raskar, an associate professor of media arts and sciences at MIT and an author of this paper, has worked extensively on developing this type of 3-D imaging. Microscopes that perform light-field imaging have been developed previously by multiple groups. In the new paper, the MIT and Austrian researchers optimized the light-field microscope, and applied it, for the first time, to imaging neural activity.

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Four Paraplegic Men Voluntarily Move Their Legs Again

Four Paraplegic Men Voluntarily Move Their Legs Again | Amazing Science |

 Four young men who have been paralyzed for years achieved groundbreaking progress -- moving their legs -- as a result of epidural electrical stimulation of the spinal cord, an international team of life scientists at the University of Louisville, UCLA and the Pavlov Institute of Physiology reported today in the medical journal Brain. The study was funded in part by the Christopher & Dana Reeve Foundation and the National Institutes of Health.

All four participants were classified with a chronic motor complete spinal cord injury and were unable to move their lower extremities prior to the implantation of an epidural stimulator. This research builds on an initial study, published in the May 2011 edition of The Lancet, which evaluated the effects of epidural stimulation in the first participant, Rob Summers, who recovered a number of motor functions as a result of the intervention.

Now three years later, the key findings documented in Brain detail the impact of epidural stimulation in four participants, including new tests conducted on Summers. What is truly revolutionary is that the second, third and fourth participants were able to execute voluntary movements immediately following the implantation and activation of the stimulator. The results and recovery time were unexpected, leading researchers to speculate that some pathways may be intact post-injury and therefore able to facilitate voluntary movements.

"Two of the four subjects were diagnosed as motor and sensory complete injured with no chance of recovery at all," Claudia Angeli, Ph.D., senior researcher, Human Locomotor Research Center at Frazier Rehab Institute, and assistant professor, University of Louisville's Kentucky Spinal Cord Injury Research Center (KSCIRC) and lead author. "Because of epidural stimulation, they can now voluntarily move their hips, ankles and toes. This is groundbreaking for the entire field and offers a new outlook that the spinal cord, even after a severe injury, has great potential for functional recovery."

These results were achieved through continual direct epidural electrical stimulation of the participants' lower spinal cords, mimicking signals the brain normally transmits to initiate movement. Once the signal was triggered, the spinal cord reengaged its neural network to control and direct muscle movements. When coupling the intervention with rehabilitative therapy, the impact of epidural stimulation intensified. Over the course of the study, the researchers noted that the participants were able to activate movements with less stimulation, demonstrating the ability of the spinal network to learn and improve nerve functions.

"We have uncovered a fundamentally new intervention strategy that can dramatically affect recovery of voluntary movement in individuals with complete paralysis even years after injury," said Susan Harkema, Ph.D., University of Louisville professor and rehabilitation research director at KSCIRC, Frazier Rehab Institute, director of the Reeve Foundation's Neuro Recovery Network and primary author of The Lancet article. "The belief that no recovery is possible and complete paralysis is permanent has been challenged."

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Brain Gate: A brain implant to restore memory

Brain Gate: A brain implant to restore memory | Amazing Science |
In the next few months, highly secretive US military researchers say they will unveil new advances toward developing a brain implant that could one day restore a wounded soldier's memory.

BrainGate™ Company’s unique technology is able to simultaneously sense the electrical activity of many individual neurons. The sensor consists of a silicon array about the size of a baby aspirin that contains one hundred electrodes, each thinner than a human hair. The array is implanted on the surface of the brain. In the BrainGate™ Neural Interface System, the array is implanted in the area of the brain responsible for limb movement. While not currently approved for use, in other future applications, the array may be implanted in areas of the brain responsible for other body processes.  While our company is focused on technology innovation and intellectual property, a number of leading academic, governmental, and health organizations are offering our BrainGate technology and related neural interfaces through clinical trials.

The human brain is a parallel processing supercomputer with the ability to instantaneously process vast amounts of information. BrainGate's™ technology allows for an extensive amount of electrical activity data to be transmitted from neurons in the brain to computers for analysis. In the current BrainGate™ system, a bundle consisting of one hundred gold wires connects the array to a pedestal which extends through the scalp. The pedestal is connected by an external cable to a set of computers in which the data can be stored for off-line analysis or analyzed in real-time. Signal processing software algorithms analyze the electrical activity of neurons and translate it into control signals for use in various computer-based applications. Intellectual property has been developed and research is underway for a wireless device as well.

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Disney Research creates first 3D-printed interactive speakers of any shape that have tactile feedback

Disney Research creates first 3D-printed interactive speakers of any shape that have tactile feedback | Amazing Science |

Scientists at Disney Research, Pittsburgh have developed methods to use a 3D printer to produce electrostatic loudspeakers that can take the shape of anything, from a rubber ducky to an abstract spiral.

The simple speakers require little assembly, but even those few manual steps might be eliminated in the future, said co-developer Yoshio Ishiguro, a Disney Research, Pittsburgh post-doctoral associate. “In five to 10 years, a 3D printer capable of using conductive materials could create the entire piece,” he predicted.

The speaker technology could be used to add sound to toys or other objects. Because the same speakers that produce audible sound also can produce inaudible ultrasound, the objects can be identified and tracked so that they can be integrated into games and other interactive systems. The objects can be touched or held in a user’s hand without a noticeable decrease in sound quality, so simple tactile feedback may also be possible.

The speakers are based on electrostatic speaker technology, which is simpler than conventional electromagnetic speakers and includes no moving parts, making it suitable for producing with a 3D printer.

An electrostatic speaker consists of a thin, conductive diaphragm and an electrode plate, separated by a layer of air. An audio signal is amplified to high voltage and applied to the electrode; as the electrode charges, an electrostatic force develops between it and the diaphragm, causing the diaphragm to deform and produce sound as the audio signal changes.

This type of speaker has relatively little bass response, but does a good job of producing high-frequency sounds, such as chirping birds, computer-generated blips and even the human voice. Sound reproduction of up to 60 decibels is possible — an appropriate level for small objects.

“What’s more, it can generate sound across the entire face of the speaker,” Ishiguro noted. That makes it possible to not only produce directional, cone-shaped speakers but also omnidirectional speakers in which the entire 3D surface emits sound.

Also, the speakers can be built with any number or configuration of electrodes; placing multiple electrodes in a curved speaker, for instance, makes it possible to vary the direction of the sound emitted.

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Brain Control with a Flash of Light: Ready for Patients?

Brain Control with a Flash of Light: Ready for Patients? | Amazing Science |
Karl Deisseroth is among a group of scientists who have been working on a way to turn brain cells on and off using genetic engineering and light.

In 2005, Stanford scientist Dr Karl Deisseroth discovered how to switch individual brain cells on and off by using light in a technique he dubbed 'optogenetics'. Research teams around the world have since used this technique to study brain cells, heart cells, stem cells and others regulated by electrical signals.

However, light-sensitive proteins were efficient at switching cells on but proved less effective at turning them off. Now, after almost a decade of research, scientists have been able to shut down the neurons as well as activate them.

Dr Deisseroth’s team has now re-engineered its light-sensitive proteins to switch cells much more adequately than before. His findings are presented in the journal Science.

It’s not as if one person had a eureka moment,” Deisseroth said. “The time had come, and it was a question of who had put the resources and effort and people” on the task, and who would get there first. But it was he and his colleagues, Edward Boyden and Feng Zhang, who took those previous discoveries and devised a practical way to turn neurons on and off with light.

Ehud Isacoff, of the University of California, Berkeley, who recently wrote about the development of the technique, said that Dr. Deisseroth “was incredibly important in getting all the parts to come together.”

In 2005 Dr. Deisseroth; Dr. Boyden and Dr. Zhang, both of whom now have their own labs at M.I.T.; and Ernst Bamberg of the Max Planck Institute of Biophysics and Georg Nagel at the University of Würzburg published a paper showing that an opsin called channelrhodopsin-2 could be used to turn on mammalian neurons with blue light.

This was the breakthrough research, but it had antecedents. In 2002 Gero Miesenböck, now at Oxford, and Boris Zemelman, now at the University of Texas, proved that optogenetics could work. Both were then at Memorial Sloan-Kettering Cancer Center. They reported their success using opsins from the fruit fly to turn on mouse neurons that had been cultured in the lab.

Dr. Isacoff reviewed the development of optogenetics recently after the awarding of the 2013 European Brain Prize to six people, including Dr. Deisseroth and Dr. Boyden, for work on optogenetics. The other winners were Dr. Bamberg, Dr. Nagel, Dr. Miesenböck and Peter Hegemann at Humboldt University in Berlin. He wrote of Dr. Miesenböck’s work, “If one had to identify the paper that launched the thousand ships of optogenetics, this is it.”

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The Human Connectome Project: Brains versus Computers [VIDEO]

The Human Connectome Project: Brains versus Computers [VIDEO] | Amazing Science |

Recent advances in noninvasive neuroimaging have set the stage for the systematic exploration of human brain circuits in health and disease. The Human Connectome Project (HCP) is systematically characterizing brain circuitry, its variability, and its relation to behavior in a population of 1,200 healthy adults (twins and their non-twin siblings). This talk reviews the progress by the HCP consortium in acquiring, analyzing, and freely sharing these massive and highly informative datasets. The HCP obtains information about structural and functional connectivity using diffusion MRI and resting-state fMRI, respectively. Additional modalities include task-evoked fMRI and MEG, plus extensive behavioral testing and genotyping. Each of these methods is powerful, yet faces significant technical limitations that are important to characterize and be mindful of when interpreting neuroimaging data. Advanced visualization and analysis methods developed by the HCP enable characterization of brain circuits in individuals and group averages at high spatial resolution and at the level of functionally distinct brain parcels and brain networks. Comparisons across subjects are beginning to reveal aspects of brain circuitry that are heritable or are related to particular behavioral capacities. Data from the HCP is being made freely available to the neuroscience community via a user-friendly informatics platform. Altogether, the HCP is providing invaluable information about the healthy human brain and its variability.

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Over the Hill at 24: Persistent Age-Related Cognitive-Motor Decline in Reaction Times Begins in Early Adulthood

Over the Hill at 24: Persistent Age-Related Cognitive-Motor Decline in Reaction Times Begins in Early Adulthood | Amazing Science |

Typically studies of the effects of aging on cognitive-motor performance emphasize changes in elderly populations. Although some research is directly concerned with when age-related decline actually begins, studies are often based on relatively simple reaction time tasks, making it impossible to gauge the impact of experience in compensating for this decline in a real world task. The present study investigates age-related changes in cognitive motor performance through adolescence and adulthood in a complex real world task, the real-time strategy video game StarCraft 2. In this study, the scientists analyze the influence of age on performance using a dataset of 3,305 players, aged 16-44 [1].

Using a piecewise regression analysis, they find that age-related slowing of within-game, self-initiated response times begins at 24 years of age. They find no evidence for the common belief expertise should attenuate domain-specific cognitive decline. Domain-specific response time declines appear to persist regardless of skill level. A second analysis of dual-task performance finds no evidence of a corresponding age-related decline. Finally, an exploratory analyses of other age-related differences suggests that older participants may have been compensating for a loss in response speed through the use of game mechanics that reduce cognitive load.

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Glass Brain: Neuroscape Lab visualizes live brain functions

Glass Brain: Neuroscape Lab visualizes live brain functions | Amazing Science |

UC San Francisco neuroscientist Adam Gazzaley, MD, PhD, is hoping to paint a fuller picture of what is happening in the minds and bodies of those suffering from brain disease with his new lab, Neuroscape, which bridges the worlds of neuroscience and high-tech.

Gazzaley aims to eliminate the need to immobilize subjects inside big, noisy machines or tether them to computers — making it impossible to simulate what it’s really like to live and interact in a complex world.

Instead, in the Neuroscape lab, wireless and mobile technologies set research participants free to move around and interact inside 3D environments, while scientists make functional recordings with an array of technologies.

Gazzaley hopes this will bring his field closer to understanding how complex neurological and psychiatric diseases really work and help doctors like him repurpose technologies built for fitness or fun into targeted therapies for their patients.

“I want us to have a platform that enables us to be more creative and aggressive in thinking how software and hardware can be a new medicine to improve brain health,” said Gazzaley, an associate professor of neurology, physiology and psychiatry and director of the UCSF Neuroscience Imaging Center.

“Often, high-tech innovations take a decade to move beyond the entertainment industry and reach science and medicine. That needs to change.”

As a demonstration of what Neuroscape can do, Gazzaley’s team created new imaging technology that he calls GlassBrain, in collaboration with the Swartz Center at UC San Diego and Nvidia, which makes high-end computational computer chips. GlassBrain creates vivid, color visualizations of the structures of the brain and the white matter that connects them, as they pulse with electrical activity in real time.

These brain waves are recorded through electroencephalography (EEG), which measures electrical potentials on the scalp. Ordinary EEG recordings look like wavy horizontal lines, but GlassBrain turns the data into bursts of rhythmic activity that speed along golden spaghetti-like connections threading through a glowing, multi-colored glass-like image of a brain.

Gazzaley is now looking at how to feed this information back to his subjects, for example by using the data from real-time EEG to make video games that adapt as people play them to selectively challenge weak brain processes.

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We must forget to avoid serious mental disorders, and forgetting is an actively regulated process

We must forget to avoid serious mental disorders, and forgetting is an actively regulated process | Amazing Science |

The human brain is build in such a way, that only necessary information is stored permanently -- the rest is forgotten over time. However, so far it was not clear if this process was active or passive. Scientists from the transfaculty research platform Molecular and Cognitive Neurosciences (MCN) at the University of Basel have now found a molecule that actively regulates memory loss. The so-called musashi protein is responsible for the structure and function of the synaptic connections of the brain, the place where information is communicated from one neuron to the next.

Using olfactory conditioning, the researchers Attila Stetak and Nils Hadziselimovic first studied the learning abilities of genetically modified ringworms (C. elegans) that were lacking the musashi protein. The experiments showed that the worms exhibited the same learning skills as unmodified animals. However, with extended duration of the experiment, the scientists discovered that the mutants were able to remember the new information much better. In other words: The genetically modified worms lacking the musashi protein were less forgetful.

Further experiments showed that the protein inhibits the synthesis of molecules responsible for the stabilization of synaptic connections. This stabilization seems to play an important role in the process of learning and forgetting. The researchers identified two parallel mechanisms: One the one hand, the protein adducin stimulates the growth of synapses and therefore also helps to retain memory; on the other hand, the musashi protein actively inhibits the stabilization of these synapses and thus facilitates memory loss. Therefore, it is the balance between these two proteins that is crucial for the retention of memories.

Forgetting is thus not a passive but rather an active process and a disruption of this process may result in serious mental disorders. The musashi protein also has interesting implications for the development of drugs trying to prevent abnormal memory loss that occurs in diseases such as Alzheimer's. Further studies on the therapeutic possibilities of this discovery will be done.

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Humans Display Only Four, Rather Than Six, Basic Emotions

Humans Display Only Four, Rather Than Six, Basic Emotions | Amazing Science |

Psychologists have long been investigating the connection between facial expressions and emotions. A theory first offered by Paul Ekman, says that there are six primary emotions that are globally recognized and easily construed through specific facial expressions: happiness, sadness, fear, anger, surprise and disgust.

According to new research published in the journal Current Biology, scientists at the University of Glasgow have discovered that there are only four basic emotions: happiness, sadness, fear/surprise and anger/disgust.

In a unique approach, the study team looked at the ‘temporal dynamics’ of facial expressions, thanks to a unique system developed at the University of Glasgow. They studied the array of different muscles inside the face involved with conveying different emotions, called ‘Action Units,’ in addition to the time-frame over which each muscle was triggered.

The scientists determined that while the facial expression signals of happiness and sadness are clearly unique across time, fear and surprise share a typical signal — the wide open eyes — at the start of the signaling mechanics. Likewise, anger and disgust share the wrinkled nose.

It is these first signals that could possibly represent simpler danger signals. Later in the signaling mechanics, facial expressions transfer signals that differentiate all six ‘classic’ facial expressions of emotion, the researchers said.

“Our results are consistent with evolutionary predictions, where signals are designed by both biological and social evolutionary pressures to optimize their function,” said study author Rachael Jack, a psychologist at the Scottish university.

“First, early danger signals confer the best advantages to others by enabling the fastest escape,” Jack explained. “Secondly, physiological advantages for the expresser – the wrinkled nose prevents inspiration of potentially harmful particles, whereas widened eyes increases intake of visual information useful for escape – are enhanced when the face movements are made early.”

“What our research shows is that not all facial muscles appear simultaneously during facial expressions, but rather develop over time supporting a hierarchical biologically-basic to socially-specific information over time,” she added.

The unique system developed by the study team uses cameras to record a three-dimensional image of participants’ faces. These participants were expressly trained to be able to activate all 42 individual facial muscles separately.

From the image, the system computer could generate a specific or random facial expression on a 3D model based on the triggering of different Action Units or clusters of units to impersonate all facial expressions.

Participants were then asked to observe the computer model as it generated various expressions and determine which emotion was being articulated. The researchers could then tell which specific Action Units observers correlate with specific emotions.

The study team discovered that the signals for fear/surprise and anger/disgust were confused at the beginning stage of transmission and only became more obvious later when other Action Units were incorporated.

“Our research questions the notion that human emotion communication comprises six basic, psychologically irreducible categories. Instead we suggest there are four basic expressions of emotion,” Jack said.

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The Beautiful Minds: Where do Savant Skills Come From?

The Beautiful Minds: Where do Savant Skills Come From? | Amazing Science |

There’s a scene in the 1988 movie Rain Man in which Raymond Babbitt (played by Dustin Hoffman) recites a waitress’s phone number. Naturally the waitress is shocked. Instead of mental telepathy, Raymond had memorized the entire telephone book and instantly recognized the name on her nametag. Hoffman’s character was heavily influenced by the life of Kim Peek, a real memory savant who recently passed away. Peek was born without a corpus callosum, the fibers that connect the right and left hemispheres of the brain. He was also born missing parts of the cerebellum, which is important for motor control and the learning of complex, well-rehearsed routines. But what Peek lacked in brain connections and conceptual cognitive functioning, he more than made up for in memory. He had the extraordinary ability to memorize any text in just one sitting. With two pages in front of him, he had the uncanny ability for each eye to focus on a different page. His repertoire included the Bible, the complete works of Shakespeare, U.S. area codes and zip codes, and roughly 12,000 other books. He was known to stop performances to correct actors and musicians who had made a mistake! He could also tell you what day of the week your birthday fell on in any year.

Savantism disproportionately affects males, with about five male savants for every one female, and the syndrome generally occurs in people with IQs between 40 and 70. Like others with ASD, when savants take IQ tests they tend to score higher on nonverbal problems than verbal problems. As Darold Treffert, a world-renowned expert on savant syndrome, observes, “IQ scores, in my experience with savants, fail to adequately capture and reflect the many separate elements and abilities that contribute to ‘intelligence’ overall in everyone.”

Even so, savants vary markedly in their abilities. Savant skills fall along a continuum, ranging from “splinter skills” (such as memorization of license plates), to “talented” savants who have musical or artistic skills that exceed what is expected based on their handicap, to “prodigious” savants where the skill is so remarkable it would be impressive with or without the disability. To date, fewer than 100 prodigious savants have been documented. Interestingly, there is almost always no “dreaded trade-off ” between the incredible skills of savants and their development of language, social skills, and daily living functioning.

How can we explain the extraordinary feats of savants? No one knows the whole story, but there are some clues. Bernard Rimland, who passed away in 2006, maintained the largest database in the world of people with autism (more than 34,000 cases). He observed that the savant skills that were most frequently present were right-hemisphere skills, and their deficits were most strongly associated with left-hemisphere functions.
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Laser Love: Mind-Altering Laser Beam Activates Heat-Sensitive Neural Pathways Involved In Courtship

Laser Love: Mind-Altering Laser Beam Activates Heat-Sensitive Neural Pathways Involved In Courtship | Amazing Science |

A flipped mental switch is all it takes to make a fly fall in love — even if its object of desire is a ball of wax. A technique called thermogenetics allows researchers to control fly behaviour by activating specific neurons with heat. Combining the system with techniques that use light to trigger neurons could help to elucidate how different neural circuits work together to control complex behaviours such as courtship.

Optogenetics — triggering neurons with light — has been successful in mice but has not been pursued much in flies, says Barry Dickson, a neuroscientist at the Howard Hughes Medical Institute's Janelia Farm Research Campus in Ashburn, Virginia. A fibre-optic cable embedded in a mouse’s brain can deliver light to cells genetically engineered to make light-activated proteins, but flies are too small for these fibre optics. Neither will these cells be activated when the flies are put into an illuminated box, because most wavelengths of visible light cannot penetrate a fly’s exoskeleton.

Heat can penetrate the exoskeleton, however. Researchers have already studied fly behaviour by adding a heat-activated protein called TRPA1 to neural circuits that control behaviours such as mating and decision-making. When these flies are placed in a hot box, the TRPA1 neurons begin to fire within minutes and drive the fly’s actions1.

But it would be better to trigger the behaviours more quickly. So Dickson’s lab has developed a system called the Fly Mind-Altering Device (FlyMAD), which uses a video camera to track the fly as it moves around in a box. The device then shines an infrared laser at the fly to deliver heat directly to the head. Dickson’s group presented the system last October at the Neurobiology of Drosophila conference at Cold Spring Harbor Laboratory in New York, and he is now submitting the work to a peer-reviewed journal.

As proof that the FlyMAD works, the group made flies with TRPA1 in a neural circuit involved in courtship. When the researchers activated the TRPA1 neurons with the laser, the fly began trying to mate with a ball of wax, circling it and 'singing' by vibrating its wings (see 'Laser love'). The fly continued courting for about fifteen minutes after the laser was shut off, suggesting that the heat had triggered a lasting, complex behavioural state. The researchers also made flies with TRPA1 in neurons involved in muscular coordination. Switching the laser on instantly made the flies walk backwards. They immediately stopped when it was switched off.

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Flies pause while 200 neurons help with tough decisions

Flies pause while 200 neurons help with tough decisions | Amazing Science |

They spend more time choosing between a strong and a weak smell if the difference is small. The research links this deliberation to a particular gene, FoxP, and the activity of fewer than 200 neurons.

Mutations in FoxP, also associated with cognition and language in humans, made flies' decisions even slower without affecting which choice they made.

Gathering information before committing to a decision is a hallmark of intelligence. If the information is unclear, the choice is trickier and the decision takes more time. We do it, other primates do it, even rats and mice do it - but now it seems that flies do too.

"This is the clearest evidence yet of a cognitive process running in a very simple brain," said Prof Gero Miesenböck, whose team did the work at the University of Oxford's Centre for Circuits and Behaviour.

"People tended to think of insects as tiny robots that just respond reflexively to signals from the environment. Now we know that's not true."

After training fruit flies to avoid a new smell at a specific intensity, the researchers offered them a choice between that dangerous odour level and a weaker one. The flies did well when the safe option was four or five times weaker, but chose randomly if the difference was only 10%.

Crucially, as the differences became smaller and trickier to distinguish, the flies took more and more time to make a decision, waiting much longer in an intermediate zone between the two odour levels.

This is a pattern that psychologists have studied for many decades. "The same mathematical models that describe human decision-making also capture the flies' behaviour perfectly," said Prof. Miesenböck.

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New brain cells erase old memories

New brain cells erase old memories | Amazing Science |
Neurogenesis interferes with past learning in infant and adult mice.

For anyone fighting to save old memories, a fresh crop of brain cells may be the last thing they need. Research published today in Sciencesuggests that newly formed neurons in the hippocampus — an area of the brain involved in memory formation — could dislodge previously learned information1. The work may provide clues as to why childhood memories are so difficult to recall.

“The finding was very surprising to us initially. Most people think new neurons mean better memory,” says Sheena Josselyn, a neuroscientist who led the study together with her husband Paul Frankland at the Hospital for Sick Children in Toronto, Canada.

Humans, mice and several other mammals grow new neurons in the hippocampus throughout their lives — rapidly at first, but more and more slowly with age. Researchers have previously shown that boosting neural proliferation before learning can enhance memory formation in adult mice23. But the latest study shows that after information is learned, neuron growth can degrade those memories.

Although seemingly counterintuitive, the disruptive role of these neurons makes some sense, says Josselyn. She notes that some theoretical models have predicted such an effect4. “More neurons increase the capacity to learn new memories in the future,” she says. “But memory is based on a circuit, so if you add to this circuit, it makes sense that it would disrupt it.” Newly added neurons could have a useful role in clearing old memories and making way for new ones, says Josselyn.

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Motion Detector: Computer Game Reveals 'Space-Time' Neurons in the Eye

Motion Detector: Computer Game Reveals 'Space-Time' Neurons in the Eye | Amazing Science |

You open the overstuffed kitchen cabinet and a drinking glass tumbles out. With a ninjalike reflex, you snatch it before it shatters on the floor, as if the movement of the object were being tracked before the information even reached your brain. According to one idea of how the circuitry of the eye processes visual data, that is literally what happens. Now, a deep anatomical study of a mouse retina—carried out by 120,000 members of the public—is bringing scientists a step closer to confirming the hypothesis.

Researchers have known for decades that the eye does much more than just detect light. The dense patch of neurons in the retina also processes basic features of a scene before sending the information to the brain. For example, in 1964, scientists showed that some neurons in the retina fire up only in response to motion. What's more, these “space-time” detectors have so-called direction selectivity, each one sensitive to objects moving in different directions. But exactly how that processing happens in the retina has remained a mystery.

The stumbling block is a lack of fine-grained anatomical detail about how the neurons in the retina are wired up to each other. Although researchers have imaged the retina microscopically in ultrathin sections, no computer algorithm has been able to accurately trace out the borders of all the neurons to map the circuitry. At this point, only humans have good enough spatial reasoning to figure out what is part of a branching cell and what is just background noise in the images.

Enter the EyeWire project, an online game that recruits volunteers to map out those cellular contours within a mouse’s retina. The game was created and launched in December 2012 by a team led by H. Sebastian Seung, a neuroscientist at the Massachusetts Institute of Technology in Cambridge. Players navigate their way through the retina one 4.5-micrometer tissue block at a time, coloring the branches of neurons along the way. Most of the effort gets done in massive online competitions between players vying to map out the most volume. (Watch a video of a player walking through a tissue block here.) By last week, the 120,000 EyeWire players had completed 2.3 million blocks. That may sound like a lot, but it is less than 2% of the retina.

The sample is already enough to reveal new features, however. The EyeWire map shows two types of retinal cells with unprecedented resolution. The first, called starburst amacrine cells (SACs), have branches spread out in a flat, plate-shaped array perpendicular to the incoming light. The second, called bipolar cells (BPs), are smaller and bushy. The BPs come in two varieties, one of which reacts to light more slowly than the other—a time delay of about 50 milliseconds. The SACs and BPs are known to be related to direction sensitivity, but exactly how they sense direction remains to be discovered.

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Oops! Researchers Find Neural Signature for Mistake Correction

Oops! Researchers Find Neural Signature for Mistake Correction | Amazing Science |

Culminating an 8 year search, scientists at the RIKEN-MIT Center for Neural Circuit Genetics captured an elusive brain signal underlying memory transfer and, in doing so, pinpointed the first neural circuit for "oops" ? the precise moment when one becomes consciously aware of a self-made mistake and takes corrective action.

The findings, published in Cell, verified a 20 year old hypothesis on how brain areas communicate. In recent years, researchers have been pursuing a class of ephemeral brain signals called gamma oscillations, millisecond scale bursts of synchronized wave-like electrical activity that pass through brain tissue like ripples on a pond. In 1993, German scientist Wolf Singer proposed that gamma waves enable binding of memory associations. For example, in a process called working memory, animals store and recall short-term memory associations when exploring the environment.

In 2006, the MIT team under the direction of Nobel Laureate Susumu Tonegawa began a study to understand working memory in mice. They trained animals to navigate a T maze and turn left or right at a junction for an associated food reward. They found that working memory required communication between two brain areas, the hippocampus and entorhinal cortex, but how mice knew the correct direction and the neural signal for memory transfer of this event remained unclear.

The study's lead author Jun Yamamoto noticed that mice sometimes made mistakes, turning in the wrong direction then pausing, and turning around to go in the correct direction, trials he termed "oops" in his lab notebook. Intrigued, he recorded neural activity in the circuit and observed a burst of gamma waves just before the "oops" moment. He also saw gamma waves when mice chose the correct direction, but not when they failed to choose the correct direction or did not correct their mistakes.

The critical experiment was to block gamma oscillations and prevent mice from making correct decisions. To do this, the researchers created a transgenic mouse with a light-activated protein called archaerhodopsin (ArchT) in the hippocampus. Using an optic fiber implanted in the brain, light was flashed into the hippocampal-entorhinal circuit, shutting off gamma activity. In accord, the mice could no longer accurately choose the right direction and the number of "oops" events decreased.

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Scientists Use Liquid Metal (Gallium-Indium-Selenium Alloy) To Reconnect Severed Nerves

Scientists Use Liquid Metal (Gallium-Indium-Selenium Alloy) To Reconnect Severed Nerves | Amazing Science |
Chinese biomedical engineers have used liquid metal to transmit electrical signals across the gap in severed sciatic nerves. The work raises the prospect of a new treatment for nerve injuries, they say.

When peripheral nerves are severed, the loss of function leads to atrophy of the effected muscles, a dramatic change in quality of life and, in many cases, a shorter life expectancy.

Despite decades of research, nobody has come up with an effective way to reconnect nerves that have been severed. Various techniques exist to sew the ends back together or to graft nerves into the gap that is created between severed ends.

Ultimately, the success of these techniques depends on the ability of the nerve ends to grow back and knit together. But given that nerves grow at the rate of one mm per day, it can take a significant amount of time, sometimes years, to reconnect. And during this time, the muscles can degrade beyond repair, leading to long-term disability.

So neurosurgeons have long hoped for a way to keep muscles active while the nerves regrow. One possibility is to electrically connect the severed ends so that the signals from the brain can still get through. But how to do this effectively?

Today, Jing Liu at Tsinghua University in Beijing and a few pals say they’ve reconnected severed nerves using liquid metal for the first time. And they say that in conducting electrical signals between the severed ends of a nerve, the metal dramatically outperforms the standard saline electrolyte used to preserve the electrical properties of living tissue.

Biomedical engineers have been eyeing the liquid metal alloy gallium-indium-selenium for some time (67 percent Ga, 20.5 percent In and 12.5 percent Sn by volume). This material is liquid at body temperature and is thought to be entirely benign. Consequently, they have been studying various ways of using it inside the body, such as for imaging.

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Brain circuits involved in emotion discovered by neuroscientists

Brain circuits involved in emotion discovered by neuroscientists | Amazing Science |
A brain pathway that underlies the emotional behaviors critical for survival have been discovered by neuroscientists. The team has identified a chain of neural connections which links central survival circuits to the spinal cord, causing the body to freeze when experiencing fear. Understanding how these central neural pathways work is a fundamental step towards developing effective treatments for emotional disorders such as anxiety, panic attacks and phobias.

New research by the University of Bristol, published in the Journal of Physiology, has identified a chain of neural connections which links central survival circuits to the spinal cord, causing the body to freeze when experiencing fear.

Understanding how these central neural pathways work is a fundamental step towards developing effective treatments for emotional disorders such as anxiety, panic attacks and phobias.

An important brain region responsible for how humans and animals respond to danger is known as the PAG (periaqueductal grey), and it can trigger responses such as freezing, a high heart rate, increase in blood pressure and the desire for flight or fight.

This latest research has discovered a brain pathway leading from the PAG to a highly localised part of the cerebellum, called the pyramis. The research went on to show that the pyramis is involved in generating freezing behaviour when central survival networks are activated during innate and learnt threatening situations.

The pyramis may therefore serve as an important point of convergence for different survival networks in order to react to an emotionally challenging situation.

Dr Stella Koutsikou, first author of the study and Research Associate in the School of Physiology and Pharmacology at the University of Bristol, said: "There is a growing consensus that understanding the neural circuits underlying fear behaviour is a fundamental step towards developing effective treatments for behavioural changes associated with emotional disorders."

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Less myelin in higher regions of the cerebral cortext may allow emergence of highly complex neuronal behaviors

Less myelin in higher regions of the cerebral cortext may allow emergence of highly complex neuronal behaviors | Amazing Science |

The higher you look in the cerebral cortex, the less myelin you'll find. Myelin, the electrical insulating material in the body long known to be essential for the fast transmission of impulses along the axons of nerve cells, is not as ubiquitous as thought, according to new work led by Professor Paola Arlotta of the Harvard Stem Cell Institute (HSCI) and the University’s Department of Stem Cell and Regenerative Biology, in collaboration with Professor Jeff Lichtman of Harvard’s Department of Molecular and Cellular Biology.

“Myelin is a relatively recent invention during evolution,” says Arlotta. “It’s thought that myelin allowed the brain to communicate really fast to the far reaches of the body, and that it has endowed the brain with the capacity to compute higher-level functions.”

In fact, loss of myelin is a feature in a number of devastating diseases, including multiple sclerosis and schizophrenia. But the new research shows that despite myelin’s essential roles in the brain, “some of the most evolved, most complex neurons of the nervous system have less myelin than older, more ancestral ones,” said Arlotta, co-director of the HSCI neuroscience program.

She said the higher one looks in the cerebral cortex — closer to the top of the brain, which is its most evolved part — the less myelin one finds.  Not only that, but “neurons in this part of the brain display a brand-new way of positioning myelin along their axons that has not been previously seen. They have ‘intermittent myelin’ with long axon tracts that lack myelin interspersed among myelin-rich segments.”

“Contrary to the common assumptions that neurons use a universal profile of myelin distribution on their axons, the work indicates that different neurons choose to myelinate their axons differently,” Arlotta said.

“In classic neurobiology textbooks, myelin is represented on axons as a sequence of myelinated segments separated by very short nodes that lack myelin. This distribution of myelin was tacitly assumed to be always the same, on every neuron, from the beginning to the end of the axon. This new work finds this not to be the case.”

The results of the research by Arlotta and postdoctoral fellow Giulio Srubek Tomassy, the first author on the report, are published in the latest edition of the journal Science.

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Scientists unveil first wiring diagram of mouse's brain

Scientists unveil first wiring diagram of mouse's brain | Amazing Science |

A year to the day after President Barack Obama announced a $100 million “BRAIN Initiative” to accelerate discoveries in how gray matter thinks, feels, remembers and sometimes succumbs to devastating diseases, scientists stated they had achieved a key milestone toward that goal.

Writing in the journal Nature, they unveiled the mouse “connectome,” a map showing the sinuous connections that neurons make throughout the mouse brain as they form functional circuits.

The mouse connectome “provides the most detailed analysis of brain circuitry currently available for any mammalian brain,” said neuroscientist David Van Essen of Washington University in St. Louis, co-leader of the human connectome project, which aims to do that for Homo sapiens. “It is truly a landmark study.”

A connectome is essentially a wiring diagram. It shows how each of the millions or billions of neurons (gray matter) in a brain each connect to thousands of other neurons through projections called axons, the white matter, and thereby allow brain regions to communicate to produce behavior, intelligence and personality.

Such a diagram could reveal, say, how neurons that register the taste of a cookie fan out to circuits that store memories and unleash a torrent of remembrances of things past. And it could reveal what causes those circuits to malfunction in diseases such as Alzheimer’s.

Before the mouse, the only species for which scientists had created an essentially complete connectome was the roundworm C. elegans. It has 302 neurons. The human brain has some 86 billion, each making as many as 10,000 connections.

A large-scale map is the goal of the Human Connectome Project, which the National Institutes of Health announced in 2010 and which Van Essen calls "one of the great scientific challenges of the 21st century." It is being produced using special technique called diffusion tensor imaging in living brains.

For the mouse connectome, scientists led by Hongkui Zeng of the Allen Institute for Brain Science in Seattle, Washington, used some of the 21st-century techniques that are required to create a human connectome. For the mouse, the key was to make neuronal connections literally shine.

The map revealed several surprises about brain wiring. Connections that stay on one side of the brain "seem to be always stronger" than those that cross hemispheres, Zeng said. The mouse's neuronal connections also vary widely in strength. That "must be contributing to brain network computation," she said. "We think a small number of strong connections and a large number of weak connections may be a fundamental network organization property to allow greater capacity of information processing."

The human connectome will resemble the Human Genome Project in a key way. Just as the genome project discovered the precise sequence of three billion molecules common to the vast majority of humans' DNA, serving as a reference book against which to measure individual genetic differences, so the connectome will first reveal neuro-commonalities and, eventually, the uniqueness of each individual brain.

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Electric “thinking cap” controls learning speed

Electric “thinking cap” controls learning speed | Amazing Science |

Caffeine-fueled cram sessions are routine occurrences on any college campus. But what if there was a better, safer way to learn new or difficult material more quickly? What if “thinking caps” were real?

In a new study published in the Journal of Neuroscience, Vanderbilt psychologists Robert Reinhart, a Ph.D. candidate, and Geoffrey Woodman, assistant professor of psychology, show that it is possible to selectively manipulate our ability to learn through the application of a mild electrical current to the brain, and that this effect can be enhanced or depressed depending on the direction of the current.

Reinhart and Woodman set out to test several hypotheses: One, they wanted to establish that it is possible to control the brain’s electrophysiological response to mistakes, and two, that its effect could be intentionally regulated up or down depending on the direction of an electrical current applied to it. This bi-directionality had been observed before in animal studies, but not in humans. Additionally, the researchers set out to see how long the effect lasted and whether the results could be generalized to other tasks.

Using an elastic headband that secured two electrodes conducted by saline-soaked sponges to the cheek and the crown of the head, the researchers applied 20 minutes of transcranial direct current stimulation (tDCS) to each subject. In tDCS, a very mild direct current travels from the anodal electrode, through the skin, muscle, bones and brain, and out through the corresponding cathodal electrode to complete the circuit. “It’s one of the safest ways to noninvasively stimulate the brain,” Reinhart said. The current is so gentle that subjects reported only a few seconds of tingling or itching at the beginning of each stimulation session.

In each of three sessions, subjects were randomly given either an anodal (current traveling from the electrode on the crown of the head to the one on the cheek), cathodal (current traveling from cheek to crown) or a sham condition that replicated the physical tingling sensation under the electrodes without affecting the brain. The subjects were unable to tell the difference between the three conditions.

After 20 minutes of stimulation, subjects were given a learning task that involved figuring out by trial and error which buttons on a game controller corresponded to specific colors displayed on a monitor. The task was made more complicated by occasionally displaying a signal for the subject not to respond—sort of like a reverse “Simon Says.” For even more difficulty, they had less than a second to respond correctly, providing many opportunities to make errors—and, therefore, many opportunities for the medial-frontal cortex to fire.

When anodal current was applied, the spike was almost twice as large on average and was significantly higher in a majority of the individuals tested (about 75 percent of all subjects across four experiments). This was reflected in their behavior; they made fewer errors and learned from their mistakes more quickly than they did after the sham stimulus. When cathodal current was applied, the researchers observed the opposite result: The spike was significantly smaller, and the subjects made more errors and took longer to learn the task. “So when we up-regulate that process, we can make you more cautious, less error-prone, more adaptable to new or changing situations—which is pretty extraordinary,” Reinhart said.

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EyeMusic: Teaching the brain of blind people to see with sound

EyeMusic: Teaching the brain of blind people to see with sound | Amazing Science |

Deprived of sight, blind people manage to squeeze an amazing amount of information out of their other senses. Doing this requires their brains to do some reorganising. To learn about some of these changes, scientists studied the brains of blind people who've learned to use an augmented reality system that converts images into soundscapes.

The system was invented in the early '90s, but it's not widely used. The way it works is a person puts on a pair of goggles with a built-in camera and software that converts images captured by the camera into sounds. For example, the pitch of the sound (high or low) indicates the vertical position of an object; the timing and duration of the sound indicate the object's horizontal position and width (you can see and hear a demo of a similar technology here). For real world scenes, the sounds are complex -- in fact, they sound a bit like a garbled transmission from an alien spacecraft.

But with enough practice people can learn to interpret the sounds and form a mental image of objects -- including people -- that appear in front of them.

When sighted people see an outline or silhouette of a human body, areas of the cerebral cortex that specialise in making sense of visual stimuli become active. One of these, the extrastriate body area, seems particularly interested in bodies: it responds more strongly to images of the human body than to other types of objects.

But blindness cuts off the usual flow of information from the eyes to this part of the brain, and people who've been blind since birth have never actually seen a human form. Something must change in their brains when they learn to perceive body shapes using sound. Do visual parts of the brain start responding to sounds? Or do auditory parts of the brain start responding to body shapes? It's a neat trick either way.

To find out what really happens, Ella Striem-Amit and Amir Amedi of the Hebrew University of Jerusalem scanned the brains of seven congenitally blind people who'd trained for an average of 73 hours on the augmented reality system. After training, they achieved 78 percent accuracy at classifying three different types of objects: people, everyday objects (like a cellphone), or textured patterns.

In some cases, they could do even more. "During training, the participants were asked to report the body posture of the people in the images they 'saw,' and could verbally describe it quite well, and also mimic it themselves," Striem-Amit said.

Striem-Amit and Amedi also found that in blind people as well as sighted people, body shapes also activated an area called the temporal-parietal junction, which some researchers think is involved in figuring out the intentions of other people.

The study illustrates that the brain can be remarkably malleable, says Kalanit Grill-Spector, a neuroscientist at Stanford University. When blind people learn to read Braille, their visual cortex becomes sensitive to touch, she notes. "However, there has been little evidence for auditory stimuli driving responses in visual cortex in the blind," Grill-Spector said. "For example making human sounds such as clapping or laughing does not seem to activate visual cortex in the blind."

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Musical Anhedonia - the inability to enjoy music - is recognized as a brain condition

Musical Anhedonia - the inability to enjoy music - is recognized as a brain condition | Amazing Science |

For most people, music is one of life's great pleasures. But the inability to enjoy it is a real condition that has just been recognized and described by science. The new condition, known as specific musical anhedonia, is described in a new paper published this week in the journal Current Biology.

People with the condition have no trouble perceiving or identifying music, or even describing the mood the music is supposed to convey, said Robert Zatorre, a McGill University neuroscientist who co-authored the paper. The condition affects about two per cent of the population. Many of those who have it said they have tried to mask their dislike of music from others.

Zatorre had previously done studies that showed music activates the pleasure and reward centres of the brain, just as food and sex do. Scientists are interested in studying the brain's reward system because problems with it are implicated in a lot of problems such as eating disorders and drug and gambling addictions.

Zatorre and colleagues in Spain, including Josep Marco-Pallares of the University of Barcelona, began to wonder if music activated the pleasure centre of the brain in everyone, or if there were some people who didn't respond the same way.

To figure that out, they surveyed around 500 students at the University of Barcelona about their music habits and response to music  — for example, did they often have music playing and did they like to share music with their friends?

Groups of students who scored high, average, and low on the questionnaire were tested in the lab for their body's response to music — changes in heart rate and skin conductance, which indicate emotional or nervous system arousal.

While those who scored average or high on the questionnaire had a strong physiological response to the music, those who scored low "more or less flatlined," Zatorre recalled, confirming that they did not derive pleasure from music.

The students were given additional questionnaires to make sure they weren't depressed and were able to experience pleasure from other things.

Then they were tested in another experiment – a slot-machine-like gambling video game in which they would sometimes receive a big payout.

"People who didn't respond to music nonetheless showed a perfectly normal response to the monetary reward," Zatorre said.

That's interesting because previously, researchers had thought the brain's reward centre was an "all or none" system that was functioning normally, hyperactive, or underactive as a whole.

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How dolphins see the world: A comparison with chimpanzees and humans

How dolphins see the world: A comparison with chimpanzees and humans | Amazing Science |

Bottlenose dolphins use auditory (or echoic) information to recognize their environments, and many studies have described their echolocation perception abilities. However, relatively few systematic studies have examined their visual perception. A team of scientists now tested dolphins on a visual-matching task using two-dimensional geometric forms including various features. Based on error patterns, they used multidimensional scaling to analyze perceptual similarities among stimuli. In addition to dolphins, they conducted comparable tests with terrestrial species: chimpanzees were tested on a computer-controlled matching task and humans were tested on a rating task. The overall perceptual similarities among stimuli in dolphins were similar to those in the two species of primates. These results clearly indicate that the visual world is perceived similarly by the three species of mammals, even though each has adapted to a different environment and has differing degrees of dependence on vision.

Because dolphins have adapted to an underwater environment, they have developed a perceptual system that differs considerably from that of terrestrial mammals such as primates. One strikingly different aspect of the perceptual system of dolphins is echolocation1,. They can recognize shapes, materials, and the texture of objects using this form of biological sonar. Many echolocation studies on cetaceans have been conducted both in the laboratory and in the wild4. A few studies have investigated dolphins' ability to use cross-modal integration through vision–echolocation matching56,. In these studies, dolphins were very accurate in matching three-dimensional complex objects using information gathered via echolocation. On the other hand, these results indirectly suggest that dolphins may also visually discriminate complex objects. Dolphins (e.g., bottlenose dolphins) have poorer in-air and underwater visual acuity (12.6 min of visual angle from a distance of 2.5 m) than that of primates10. Nevertheless, they still visually recognize and discriminate human gestural signs111213, mirror images of themselves1415, numbers of objects16, three-dimensional objects417, and two-dimensional forms1718. Moreover, researchers have used visual stimuli to study the basic features of the vision and various cognitive abilities of dolphins1718.

Casper Pieters's curator insight, March 9, 2014 7:28 PM

Great visual for bio studies.