(Image caption: The EyeCane: (A) A flow chart depicting the use of the device and an illustration of a user. Note the two sensor beams, one pointing directly ahead, and one pointing towards the ground for obstacle detection. (B) Photo of the “EyeCane.”)

User-Friendly Electronic “EyeCane” Enhances Navigational Abilities for the Blind

White Canes provide low-tech assistance to the visually impaired, but some blind people object to their use because they are cumbersome, fail to detect elevated obstacles, or require long training periods to master. Electronic travel aids (ETAs) have the potential to improve navigation for the blind, but early versions had disadvantages that limited widespread adoption. A new ETA, the “EyeCane,” developed by a team of researchers at The Hebrew University of Jerusalem, expands the world of its users, allowing them to better estimate distance, navigate their environment, and avoid obstacles, according to a new study published in Restorative Neurology and Neuroscience. 

“The EyeCane was designed to augment, or possibly in the more distant future, replace the traditional White Cane by adding information at greater distances (5 meters) and more angles, and most importantly by eliminating the need for contacts between the cane and the user’s surroundings [which makes its use difficult] in cluttered or indoor environments,” says Amir Amedi, PhD, Associate Professor of Medical Neurobiology at The Israel-Canada Institute for Medical Research, The Hebrew University of Jerusalem.

The EyeCane translates point-distance information into auditory and tactile cues. The device is able to provide the user with distance information simultaneously from two different directions: directly ahead for long distance perception and detection of waist-height obstacles and pointing downward at a 45° angle for ground-level assessment. The user scans a target with the device, the device emits a narrow beam with high spatial resolution toward the target, the beam hits the target and is returned to the device, and the device calculates the distance and translates it for the user interface. The user learns intuitively within a few minutes to decode the distance to the object via sound frequencies and/or vibration amplitudes.

Recent improvements have streamlined the device so its size is 4 x 6 x 12 centimeters with a weight of less than 100 grams. “This enables it to be easily held and pointed at different targets, while increasing battery life,” says Prof. Amedi.

The authors conducted a series of experiments to evaluate the usefulness of the device for both blind and blindfolded sighted individuals. The aim of the first experiment was to see if the device could help in distance estimation. After less than five minutes of training, both blind and blindfolded individuals were able to estimate distance successfully almost 70% of the time, and the success rate surpassed 80% for two of the three blind participants. “It was amazing seeing how this additional distance changed their perception of their environment,” notes Shachar Maidenbaum, one of the researchers on Prof. Amedi’s team. “One user described it as if her hand was suddenly on the far side of the room, expanding her world.”

A second experiment looked at whether the EyeCane could help individuals navigate an unfamiliar corridor by measuring the number of contacts with the walls. Those using a White Cane made an average of 28.2 contacts with the wall, compared to three contacts with the EyeCane – a statistically significant tenfold reduction. A third experiment demonstrated that the EyeCane also helped users avoid chairs and other naturally occurring obstacles placed randomly in the surroundings.

“One of the key results we show here is that even after less than five minutes of training, participants were able to complete the tasks successfully,” says Prof. Amedi. “This short training requirement is very significant, as it make the device much more user friendly. Every one of our blind users wanted to take the device home with them after the experiment, and felt they could immediately contribute to their everyday lives,” adds Maidenbaum.

The Amedi lab is also involved in other projects for helping people who are blind. In another recent publication in Restorative Neurology and Neuroscience they introduced the EyeMusic, which offers much more information, but requires more intensive training. “We see the two technologies as complementar,y” says Prof. Amedi. “You would use the EyeMusic to recognize landmarks or an object and use the EyeCane to get to it safely while avoiding collisions.”

A video demonstration of the EyeCane is available at http://www.youtube.com/watch?v=rpbGaPxUKb4

Brain mechanism underlying the recognition of hand gestures develops even when blind

Does a distinctive mechanism work in the brain of congenitally blind individuals when understanding and learning others’ gestures? Or does the same mechanism as with sighted individuals work? Japanese researchers figured out that activated brain regions of congenitally blind individuals and activated brain regions of sighted individuals share common regions when recognizing human hand gestures. They indicated that a region of the neural network that recognizes others’ hand gestures is formed in the same way even without visual information. The findings are discussed in The Journal of Neuroscience.

Our brain mechanism perceives human bodies from inanimate objects and shows a particular response. A part of a region of the “visual cortex” that processes visual information supports this mechanism. Since visual information is largely used in perception, this is reasonable, however, for perception using haptic information and also for the recognition of one’s own gestures, it has been recently learned that the same brain region is activated. It came to be considered that there is a mechanism that is formed regardless of the sensory modalities and recognizes human bodies.

Blind and sighted individuals participated in the study of the research group of Assistant Professor Ryo Kitada of the National Institute for Physiological Sciences, National Institutes of Natural Sciences. With their eyes closed, they were instructed to touch plastic casts of hands, teapots, and toy cars and identify the shape. As it turned out, sighted individuals and blind individuals could make an identification with the same accuracy. Through measuring the activated brain region using functional magnetic resonance imaging (fMRI), for plastic casts of hands and not for teapots or toy cars, the research group was able to pinpoint a common activated brain region regardless of visual experience. On another front, it also revealed a region showing signs of activity that is dependent on the duration of the visual experience and it was also learned that this region functions as a supplement when recognizing hand gestures.

As Assistant Professor Ryo Kitada notes, “Many individuals are active in many parts of the society even with the loss of their sight as a child. Developmental psychology has been advancing its doctrine based on sighted individuals. I wish this finding will help us grasp how blind individuals understand and learn about others and be seen as an important step in supporting the development of social skills for blind individuals.”

Congenitally blind visualise numbers opposite way to sighted

For the first time, scientists have uncovered that people blind from birth visualise numbers the opposite way around to sighted people.

Through a recent study, the researchers in our Department of Psychology were surprised to find that the ‘mental number line’ for congenitally blind people ran in the opposite direction to sighted people, with larger numbers to the left and smaller numbers to the right.

Whereas a sighted person would count 1, 2, 3, 4, 5, the researchers have found that someone blind from birth mentally visualises their number line from right to left, effectively 5, 4, 3, 2, 1.

Senior Lecturer from the Department, Dr Michael Proulx explained: “Our unexpected results relate to the fact that people who were born visually impaired like to map the position of objects in relation to themselves.

“It is likely that this style of spatial representation extends to numbers too, and the right-handed participants mapped the number line from their dominant right hand.”

The study used a novel ‘random number generation’ procedure where volunteers were asked to say numbers while turning their head to the left or the right. This task is linked to how the brain visualises a mental number line.

As part of the study, an international team from Bath, Sabanci University (Turkey) and Taisho University (Japan) compared responses of congenitally blind people, with the adventitiously blind – those who were born with vision – and sighted, but blindfolded, volunteers.

Previous studies have shown that people in Western cultures, where writing runs from left to right, possess a similar mental number line, with small numbers on the left and larger numbers on the right. But in cultures where writing flows from right to left, for example Arabic, people’s mental number lines runs in a similar direction. This is the first time scientists have uncovered that blind individuals in a Western culture also had a right to left number line.

Dr Proulx added: “Remembering and representing numbers is an important skill, and the foundation of mental maths. Visually impaired people are just as good, if not better, at mathematics than sighted people – Georgian Maths Professor and Royal Society Fellow, Nicholas Saunderson as one famous example.

“What makes this work exciting is that Saunderson may have been able to advance mathematics with an entirely different mental representation of numbers than that of sighted contemporaries like Isaac Newton.”

Detecting Unidentified Changes

Does becoming aware of a change to a purely visual stimulus necessarily cause the observer to be able to identify or localise the change or can change detection occur in the absence of identification or localisation? Several theories of visual awareness stress that we are aware of more than just the few objects to which we attend. In particular, it is clear that to some extent we are also aware of the global properties of the scene, such as the mean luminance or the distribution of spatial frequencies. It follows that we may be able to detect a change to a visual scene by detecting a change to one or more of these global properties. However, detecting a change to global property may not supply us with enough information to accurately identify or localise which object in the scene has been changed. Thus, it may be possible to reliably detect the occurrence of changes without being able to identify or localise what has changed. Previous attempts to show that this can occur with natural images have produced mixed results. Here we use a novel analysis technique to provide additional evidence that changes can be detected in natural images without also being identified or localised. It is likely that this occurs by the observers monitoring the global properties of the scene.

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Vision is key to spatial skills

Try to conjure a mental image of your kitchen, or imagine the route that you take to work every day. For most people, this comes so naturally that we think nothing of it, but for neuroscientists, there is still much to learn about how the brain develops this critical skill, known as spatial imagery.

Sensory information from the eyes, ears, and sense of touch all contribute to our ability to imagine spatial structures, but questions remain about the influence of each sensory system. A new study from MIT neuroscientists suggests that visual input plays a special role in developing these skills, particularly for more complex tasks.

By studying children in India who were born blind but whose blindness could be treated, the researchers found that the children’s ability to perform more complex spatial imagery tasks improved markedly following surgery that restored their sight.

“Just four months of vision seems to have a significant impact on spatial imagery skills,” says Pawan Sinha, an MIT professor of brain and cognitive sciences and senior author of the paper. “That seems to be consistent with the greater richness of spatial information that vision provides. With audition and touch we get a coarser sense of the environment. With vision we have a much more fine-grained appreciation of the environment.”

The study, which appeared in a recent issue of the journal Psychological Science, grew out of Project Prakash, a charitable effort Sinha launched to identify and treat children in India suffering from curable forms of blindness, such as cataracts or corneal scarring.

Tapan Gandhi, a postdoc in Sinha’s lab, is the paper’s lead author; Suma Ganesh, an ophthalmologist at Dr. Shroff’s Charity Eye Hospital in New Delhi, is also an author.

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Image caption: When adult mice were kept in the dark for about a week, neural networks in the auditory cortex, where sound is processed, strengthened their connections from the thalamus, the midbrain’s switchboard for sensory information. As a result, the mice developed sharper hearing. This enhanced image shows fibers (green) that link the thalamus to neurons (red) in the auditory cortex. Cell nuclei are blue. Image by Emily Petrus and Amal Isaiah

A Short Stay in Darkness May Heal Hearing Woes

Call it the Ray Charles Effect: a young child who is blind develops a keen ability to hear things others cannot. Researchers have known this can happen in the brains of the very young, which are malleable enough to re-wire some circuits that process sensory information. Now researchers at the University of Maryland and Johns Hopkins University have overturned conventional wisdom, showing the brains of adult mice can also be re-wired, compensating for a temporary vision loss by improving their hearing.

The findings, published Feb. 5 in the peer-reviewed journal Neuron, may lead to treatments for people with hearing loss or tinnitus, said Patrick Kanold, an associate professor of biology at UMD who partnered with Hey-Kyoung Lee, an associate professor of neuroscience at JHU, to lead the study.

"There is some level of interconnectedness of the senses in the brain that we are revealing here," Kanold said.

"We can perhaps use this to benefit our efforts to recover a lost sense," said Lee. "By temporarily preventing vision, we may be able to engage the adult brain to change the circuit to better process sound."

Kanold explained that there is an early “critical period” for hearing, similar to the better-known critical period for vision. The auditory system in the brain of a very young child quickly learns its way around its sound environment, becoming most sensitive to the sounds it encounters most often. But once that critical period is past, the auditory system doesn’t respond to changes in the individual’s soundscape.

"This is why we can’t hear certain tones in Chinese if we didn’t learn Chinese as children," Kanold said. "This is also why children get screened for hearing deficits and visual deficits early. You cannot fix it after the critical period."

Kanold, an expert on how the brain processes sound, and Lee, an expert on the same processes in vision, thought the adult brain might be flexible if it were forced to work across the senses rather than within one sense. They used a simple, reversible technique to simulate blindness: they placed adult mice with normal vision and hearing in complete darkness for six to eight days.

After the adult mice were returned to a normal light-dark cycle, their vision was unchanged. But they heard much better than before.

The researchers played a series of one-note tones and tested the responses of individual neurons in the auditory cortex, a part of the brain devoted exclusively to hearing. Specifically, they tested neurons in a middle layer of the auditory cortex that receives signals from the thalamus, a part of the midbrain that acts as a switchboard for sensory information. The neurons in this layer of the auditory cortex, called the thalamocortical recipient layer, were generally not thought to be malleable in adults.

But the team found that for the mice that experienced simulated blindness these neurons did, in fact, change. In the mice placed in darkness, the tested neurons fired faster and more powerfully when the tones were played, were more sensitive to quiet sounds, and could discriminate sounds better. These mice also developed more synapses, or neural connections, between the thalamus and the auditory cortex.

The fact that the changes occurred in the cortex, an advanced sensory processing center structured about the same way in most mammals, suggests that flexibility across the senses is a fundamental trait of mammals’ brains, Kanold said.

"This makes me hopeful that we would see it in higher animals too," including humans, he said. "We don’t know how many days a human would have to be in the dark to get this effect, and whether they would be willing to do that. But there might be a way to use multi-sensory training to correct some sensory processing problems in humans."

The mice that experienced simulated blindness eventually reverted to normal hearing after a few weeks in a normal light-dark cycle. In the next phase of their five-year study, Kanold and Lee plan to look for ways to make the sensory improvements permanent, and to look beyond individual neurons to study broader changes in the way the brain processes sounds.

Cells from the eye are inkjet printed for the first time

A group of researchers from the UK have used inkjet printing technology to successfully print cells taken from the eye for the very first time.

The breakthrough, which has been detailed in a paper published today, 18 December, in IOP Publishing’s journal Biofabrication, could lead to the production of artificial tissue grafts made from the variety of cells found in the human retina and may aid in the search to cure blindness.

At the moment the results are preliminary and provide proof-of-principle that an inkjet printer can be used to print two types of cells from the retina of adult rats―ganglion cells and glial cells. This is the first time the technology has been used successfully to print mature central nervous system cells and the results showed that printed cells remained healthy and retained their ability to survive and grow in culture.

Co-authors of the study Professor Keith Martin and Dr Barbara Lorber, from the John van Geest Centre for Brain Repair, University of Cambridge, said: “The loss of nerve cells in the retina is a feature of many blinding eye diseases. The retina is an exquisitely organised structure where the precise arrangement of cells in relation to one another is critical for effective visual function”.

“Our study has shown, for the first time, that cells derived from the mature central nervous system, the eye, can be printed using a piezoelectric inkjet printer. Although our results are preliminary and much more work is still required, the aim is to develop this technology for use in retinal repair in the future.”

The ability to arrange cells into highly defined patterns and structures has recently elevated the use of 3D printing in the biomedical sciences to create cell-based structures for use in regenerative medicine.

In their study, the researchers used a piezoelectric inkjet printer device that ejected the cells through a sub-millimetre diameter nozzle when a specific electrical pulse was applied. They also used high speed video technology to record the printing process with high resolution and optimised their procedures accordingly.

“In order for a fluid to print well from an inkjet print head, its properties, such as viscosity and surface tension, need to conform to a fairly narrow range of values. Adding cells to the fluid complicates its properties significantly,” commented Dr Wen-Kai Hsiao, another member of the team based at the Inkjet Research Centre in Cambridge.

Once printed, a number of tests were performed on each type of cell to see how many of the cells survived the process and how it affected their ability to survive and grow.

The cells derived from the retina of the rats were retinal ganglion cells, which transmit information from the eye to certain parts of the brain, and glial cells, which provide support and protection for neurons.

“We plan to extend this study to print other cells of the retina and to investigate if light-sensitive photoreceptors can be successfully printed using inkjet technology. In addition, we would like to further develop our printing process to be suitable for commercial, multi-nozzle print heads,” Professor Martin concluded.