Vision Archives | Research & Innovation

How do we know where things are? New study examines visual stabilization

ls1207 — Tue, 13 Jul 2021 16:40:29 +0000

Our eyes move three times per second. Every time we move our eyes, the world in front of us flies across the retina at the back of our eyes, dramatically shifting the image the eyes send to the brain; yet, as far as we can tell, nothing appears to move.

A new study out of 91��ɫ and Dartmouth College provides new insight into this process known as "visual stabilization." The results are published in the��.

Patrick Cavanagh

"Our results show that a framing strategy is at work behind the scenes all the time, which helps stabilize our visual experience," says senior author Patrick Cavanagh, a senior research fellow in psychology at both Glendon Campus and the Centre for Vision Research at 91��ɫ and a research professor in psychological and brain sciences at Dartmouth College. "The brain has its own type of steadycam, which uses all sorts of cues to stabilize what we see relative to available frames, so that we don't see a shaky image like we do in handheld movies taken with a smartphone. The visual world around us is the ultimate stable frame but our research shows that even small frames work: the locations of a test within the frame will be perceived relative to the frame as if it were stationary. The frame acts to stabilize your perception."

One such example is when someone waves goodbye to you from the window of a moving bus. Their hand will appear as if it's moving up and down relative to the window rather following the snake-like path that it actually traces out from the moving bus. The bus window acts like a frame through which the motion of the hand waving good-bye is seen relative to that frame.

The study consisted of two experiments that tested how a small square frame moving on a computer monitor affected participants' judgments of location. The experiments were conducted in-person with eight individuals including two of the authors; and also online due to the COVID-19 pandemic with 274 participants recruited from 91��ɫ of which 141 had complete data. The data were very similar for both types of participants.

In Experiment 1, a white, square frame moves left and right, back and forth, across a grey screen and the left and right edges of the square flash when the square reaches the end of its path: the right edge flashes blue at one end of the travel and the left edge flashes red at the other (see��), as shown in the figure below. Participants were asked to adjust a pair of markers at the top of the screen to indicate the distance they saw between the flashed edges.

In Experiment 1, the frame moves left and right but instead of seeing the locations of the blue and red edges where they are when they flash, they always appear with the blue flash on the left and separated by the width of the frame, as if the frame were not moving. When the frame moves more than its width as shown here, the red edge is physically to the left of the blue when they flash at the end of the frame's motion, and yet the blue still appears to the left of red, separated again by almost the width of the frame

Experiment 1 had two conditions: The first condition evaluated how far apart the outer left and right edges of the square frame appeared; the second condition assessed the travel of the frame's physical edge.

The data from both conditions of Experiment 1 demonstrated that participants perceived the flashed edges of the frame as if it were stable even though it was clearly moving, illustrating what the researchers call the "paradoxical stabilization" produced by a moving frame.

Experiment 2 again demonstrated the stabilizing power of a moving frame by flashing a red disc and a blue disc at the same location within a moving frame (see ). The square frame moves back and forth from left to right while the disc flashes red and blue in alternation. As in Experiment 1, participants were asked to indicate the perceived separation between the red and blue discs. Even though there is no physical separation between the discs, the moving frame creates the appearance that the two discs are located to the left and right of their true locations, relative to the frame where they flashed. In other words, participants perceived the location of the discs relative to the frame, as if it were stationary and this was true across a wide range of frame speeds, sizes, and path lengths.

"By using flashes inside a moving frame, our experiments triggered a paradoxical form of visual stabilization, which made the flashes appear in positions where they were never presented," says Cavanagh. "Our results demonstrate a 100 per cent stabilization effect triggered by the moving frames - the motion of the frame has been fully discounted.”

These data, he says, are the first to show a frame effect that matches our everyday experience where, each time our eyes move, the motion of the scene across our retinas has been fully discounted making the world appear stable.

"In the real-world, the scene in front of us acts as the anchor to stabilize our surroundings," Cavanagh says. Discounting the motion of the world as our eye move makes a lot of sense, as most scenes (i.e. house, workplace, school, outdoor environment) are not moving, unless an earthquake is occurring.

"Every time our eyes move, there's a process that blanks out the massive blur caused by the eye movement. Our brain stitches this gap together so that we don't notice the blank, but it also uses the motion to stabilize the scene. The motion is both suppressed and discounted so that we can keep track of the location of objects in the world," says Cavanagh.

Based on the study's results, the research team plans to explore visual stabilization further using brain imaging at 91��ɫ Dartmouth.

Mert Özkan, a graduate student in the Department of Psychological and Brain Sciences at Dartmouth; Stuart Anstis, professor emeritus in psychology at the University of California San Diego; Bernard M. ’t Hart, a postdoc at the Centre for Vision Research at 91��ɫ; and Mark Wexler, Chargé de Recherche at the Integrative Neuroscience and Cognition Center at the Université de Paris, also served as co-authors of the study.

Courtesy of YFile.

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Vision researchers undertake cutting-edge work on perception, orientation

muellerm — Thu, 05 Mar 2020 10:00:00 +0000

VISTA and the Centre for Vision Research at 91��ɫ U are breaking new ground in fundamental and applied research in the vision sciences. Professor Robert Allison and Pearl Guterman, PhD, recently published compelling new research on perception and balance.

Everyday activities that we take for granted, such walking, riding a bike or even sitting still, depend on our sense of equilibrium. Gravity provides an ever-present downward pull that we need to sense in order to balance effectively. Visual cues, such as knowing a tree trunk is rooted in the ground, assist in this process.

Gravity provides an ever-present downward pull that we need to sense in order to balance effectively

Pearl Guterman

Pearl Guterman��(BSc ’05, BA ’06, MA ’09, PhD ’16) a grad student at the time of the research, and Lassonde School of Engineering Professor��Robert Allison��made an important discovery in the field of vision and perception: they confirmed the A-effect, the phenomenon of perceiving a vertical line as tilted towards the body when tilting your head sideways in the dark, and showed that a similar misperception applied to perceived direction of visual motion. They also found that the A-effect is stronger when people feel like they’re moving compared to when they see this motion as coming from the external world.

Robert Allison

The findings were published in��Vision��(2019). The research was funded by National Science and Engineering Research Council of Canada and the Canadian Space Agency.

Allison is a core member of the Vision: Science to Application (VISTA) program, associate director of the Centre for Vision Research (CVR) and a 91��ɫ Research Chair in Stereoscopic Vision and Depth Perception. Guterman, now a PhD, is a principal in Applied Intelligence at Accenture.

The two researchers sat down with��Brainstorm��to talk about the significance of this work.

Q: What were the objectives of this study?

PG:��We wanted to see whether the A-effect occurs when scene motion shown to stationary observers generated a compelling illusion of self-motion (such as walking or driving) called vection. Vection is similar to the feeling of motion that you experience when sitting in a stationary train and viewing another train moving on an adjacent track: you feel like you’re moving as well.

What’s interesting about vection is that it occurs despite a conflict between what you are seeing and what your inner ear is sensing.

Vection is the compelling illusion of self-motion

RA:��With the A-effect, if you tilt to one side, something that’s vertical appears to tilt with you. So you might think that you misestimated how much your body is tilted. The interesting thing about vection is that it’s very body centric. You feel like you’re moving, but it’s an external vision signal.

“The CRV is a world-renowned research leader in biological and machine vision research.” – Robert Allison

Q: Please describe the experiment. ��

Apparatus for the upright and tilted posture used in the experiment

PG:��We conducted two experiments where participants (from the 91��ɫ community) in various postures viewed a line or dot motion scene that was vertical or tilted (from vertical relative to gravity). The motion was either in 2D, and it looked like a dotted wallpaper, or in 3D, which was more consistent with real self-motion.

In this experiment, participants only had to do one thing: indicate whether the line or scene appeared to be tilted clockwise or counterclockwise from vertical.

In the first experiment, with 20 participants, we just wanted to see whether there was an A-effect for motion in general. In the second experiment, with eight participants, we were interested in whether this effect also occurred when you felt like you were moving (experiencing vection), so we compared 3D motion of short and long duration.

Q: What was the key finding?

PG:��We found that the A-effect is stronger when people felt like they were moving compared to when they saw this motion as coming from the external world. This makes sense because vection already involves a conflict in terms of what you’re seeing versus what you’re experiencing.

“The highly interdisciplinary and collaborative nature of research at the CVR, along with leading-edge facilities, has made it a font of scientific discoveries and technological innovations.” – Pearl Guterman

Q: Did anything surprise you?

RA:��This vection result did surprise us as we had made the opposite hypothesis. We have an explanation for the results, but it wasn’t what we expected.

PG:��What also surprised us was that the vection tilt judgments were more precise and consistently so. This suggests that a different strategy (involving other transformations in the brain) is being used to determine the tilt, when you feel like you’re moving, in estimating self-motion direction than for motion in general.

In this experiment, the motion was either in 2D, and it looked like a dotted wallpaper, or in 3D which was more consistent with real self-motion

Q: Is this original work?

RA:��Yes. Only one other group has ever looked at motion, and no one has ever considered self-motion.

Q: How could this research be applied?

PG:��This has many applications, particularly operating in space, which is why this work was supported by the Canadian Space Agency. For instance, it could be applied to remotely operating robotics since the operator’s moving view could potentially cause them to misinterpret the direction of their device or other objects.

The findings of this study could also help us to better understand why the perception of vertical tends to be misjudged in a wide range of neurological conditions.

Q: What can you say about 91��ɫ’s leadership in vision research?

RA:��91��ɫ has a long history, stretching back to the 1970s, of expertise in this particular area. We’ve got unique facilities like the tumbling room. We’ve got people like myself, Laurence Harris, Michael Jenkin and the late Ian Howard, the founder of the CVR, who have looked at this specific issue of orientation with respect to gravity.

This centre is a world-renowned research leader in biological and machine vision research, consisting of researchers from all disciplines including the sciences and media arts.

PG:��The highly interdisciplinary and collaborative nature of research at the CVR, along with leading-edge facilities, has made it a fount of scientific discoveries and technological innovations.

RA:��91��ɫ’s research on vection is continuing in space with ongoing experiments on self-motion perception in astronauts aboard the International Space Station.

To read the article in��Vision��(2019), visit the��. To learn more about Allison, visit the��.

To learn more about Research & Innovation at 91��ɫ, follow us at��; watch our new��, which profiles current research strengths and areas of opportunity, such as Artificial Intelligence and Indigenous futurities; and see the��, a glimpse of the year’s successes.

By Megan Mueller, senior manager, Research Communications, Office of the Vice-President Research & Innovation, 91��ɫ,��muellerm@yorku.ca

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Canada Research Chair creates extraordinary art installation in Korea

muellerm — Fri, 02 Feb 2018 10:00:00 +0000

91��ɫ U’s Graham Wakefield, core member of VISTA, participates in a groundbreaking art exhibit in Seoul, Korea: He and fellow artist-researcher create an unforgettable virtual reality experience.

Graham Wakefield

It’s hard to imagine an aesthetic experience that weaves together art, music, virtual reality, mathematics, philosophy and software engineering to create an out-of-this-world encounter. If you were in Seoul, Korea last fall, you may have been lucky enough to experience this first hand.

Last October, 91��ɫ Professor Graham Wakefield, Canada Research Chair in Interactive Information Visualization, contributed to an art exhibit at South Korea’s Seoul Museum of Art. “Requiem for Hybrid Life,” curated by Kyoungmi Kim of the New Media Art Research Association, ran from Oct. 17 to 23, 2017, and featured the work of Wakefield and fellow artist-researcher and recent 91��ɫ Visiting Professor Haru Ji.

“Requiem for Hybrid Life” flyer. Reproduced with permission of the New Media Research Association

What Wakefield and Ji created, after a feverish four-day installation process, was breathtaking.

“The excitement created by new immersive technologies that can generate life-like interactive experiences parallels the enthusiasm brought about by the birth of cinema,” says Wakefield. “Interactive virtual worlds and mixed realities will be increasingly important forms of creative content in the future,” he adds.

Wakefield, who came to 91��ɫ three years ago, is a core member of the high-profile Vision: Science to Application (VISTA) program and the director of the Alice Lab for Computational Worldmaking in the School of the Arts, Media, Performance & Design (AMPD), which constructs responsive artificial worlds experienced through mixed/hybrid reality technologies, including Virtual and Augmented Reality.

“Conservation of Shadows” integrates with historically charged space, creates something new

The title of Wakefield and Ji’s installation piece in the Seoul show is “Conservation of Shadows” (2017). Part of an ongoing series called “Artificial Nature,” it is composed of 330 kilograms of salt; 12 nD::Node programmable circuit boards used to write and upload computer code developed by fellow AMPD researcher Professor Mark-David Hosale; 72 vibration motors, 132 bells, 150 meters of wire, two Kinect 360s, motion detectors for computers; and one HTC Vive HMD, which is a virtual reality system.

Model for “Conservation of Shadows”

The Seoul exhibition space is quite large and barn-like with old timbers through which one can see the sky during daylight hours. It is rich in history that directly contributed to the installation, as part of the overall experience: “This building, an extension of the Seoul Museum of Art, used to be part of the Korean government’s Centre for Disease Control and Prevention. It was used for the storage of infectious diseases and materials and various other forms of biological matter. So, it has a very charged atmosphere,” Wakefield explains.

What visitors experience is unparalleled

Close up on bells in the installation space

Visitors enter the vast, dimly lit room, which features a series of well-placed bells – 132 miniature bells, in fact – attached to cables hanging from the ceiling like organic tendrils. The bells and their circuits were constructed with the assistance of four students in 91��ɫ’s Digital Media program: Nicholas Abbruzzese, Filiz Eryilmaz, Adiola Palmer and Amir Bahador Rostami.

The resulting sound creates a haunting interactive ambience. “The miniature bells are activated by small vibration motors — the same kind that makes a cell phone vibrate. These bells and motors surround the installation space, hanging down from the rafters at different locations and different heights,” Wakefield explains. “The bells aren’t perfectly manufactured, so each has a slightly different tone, which helps create a richer and more variegated sonic experience,” he adds.

Visitors feel and hear the salt granules crunching underfoot with each step as they progress farther into this engaging environment. Shadowy images, ghostly vortexes that represent other life forces, are projected downward from the ceiling where they mingle with the visitors’ shadows – each such interaction being distinct, unpredictable and impossible to replicate.

“Conservation of Shadows” (2017) Graham Wakefield and Haru Ji

Those individuals choosing the virtual reality option can experience another layer, a different reality, where they witness mesmerizing, three-dimensional (3-D) flecks of dancing white formations that move together like a murmuration of birds against a limitless black background. In this alternative reality, fellow visitors to the installation space are captured as mysterious black voids, fully incorporated into the virtual reality setting. In this way, the visitors themselves become shadows that, again, interact with the projected shadows.

The bells are also replicated in the virtual reality space, such that the motors become more active and the bells ring more intensively when triggered. The effect ��̶�� organic, technological and metaphysical ��̶ ��is unforgettable.

Wakefield wanted the images and sensations to swim together to create a compelling imagined world. He describes this process: “We imagined unknown new beings growing fond of the wet texture of old wood [timbers overhead], the fragrance of sunshine smeared between cracks, and the quietness of murmuring and whispering. To let the new beings live, we extended senses to mix realities surrounded by softly ringing bells and the crunch of salt underfoot as their shadows pass by; and an alternate perspective through head-mounted display in which we become the shadows around which new beings play.”

These static two-dimensional images offer a glimpse of what the dynamic 3-D images look like in the virtual reality option

Audience response was overwhelmingly positive. “One of the comments that we received, many times, was how well the installation fit the space, given its unique character and history,” says Wakefield.

Wakefield’s work will shape future of arts and entertainment sectors

Wakefield’s forward-looking work will lead to the development of new artworks and technologies for emerging art forms and creative industries. His research will help meet the demand for more immersive, dynamic and open-ended interactive experiences in the arts and entertainment sectors.

“Entertainment and software industries are already investing heavily in these areas while acknowledging the need for new software and aesthetic practices,” says Wakefield.

To learn more about Wakefield, visit his . For more information about “Artificial Nature,” visit the . To learn more about the Alice Lab for Computational Worldmaking, visit the website.

To learn more about Research & Innovation at 91��ɫ, follow us at , watch the and see the .

By Megan Mueller, manager, research communications, Office of the Vice-President Research & Innovation, 91��ɫ, muellerm@yorku.ca

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12-week dance class helps those with Parkinson’s disease

muellerm — Fri, 06 Oct 2017 08:00:00 +0000

Joseph DeSouza

An NSERC-funded project, where patients with Parkinson’s participated in three-month dance classes, has led to the patients’ improvements in balance and gait speed.

Highly collaborative research led by 91��ɫ’s Centre for Vision Research, alongside the National Ballet of Canada and Ryerson University, offers new hope to those with Parkinson’s disease (PD). The project, funded by the National Science and Engineering Research Council (NSERC), the Parkinson’s Society Canada and donation from the Irpinia Club of Toronto, looked at the benefits of a 12-week dance intervention for patients with Parkinson’s.

This ground-breaking research, led by Professor Joseph DeSouza (with PhD student Karolina Bearss and honours student Katherine McDonald) wove together the insights of many departments, including Biology, Psychology, the Neuroscience Graduate Diploma Program and Interdisciplinary Studies, as the 91��ɫ team worked with Rachel Bar of Canada’s National Ballet School and Ryerson University.

“This research shows, for the very first time, long-term changes related to participation in a 12-week dance program,” DeSouza explains. “The results indicate motor improvements for both balance and gait in short-term – one day – and long-term – 12 weeks,” he adds.

Roughly 70,000 Canadians living with Parkinson’s

The second-most common neurodegenerative disease after Alzheimer’s, Parkinson’s is a progressive degenerative disease that affects mainly those over 60 years of age (Statistics Canada). Diagnosed by symptoms alone, common signs are tremor, slowness of movement and stiffness, impaired balance and coordination, and rigidity of the muscles (Parkinson Canada).

Just under 70,000 Canadians are living with Parkinson’s today (55,000 adults in addition to 12,500 residents of long-term care facilities), according to Statistics Canada.

The rate of progression of this disease varies greatly among patients. As there is no cure, several therapies have proven beneficial to help manage the symptoms. Interestingly, research in this field has shifted its attention away from drug therapies – in part, due to negative side effects – to forms of interventions, such as dance, intended to improve daily functioning and quality of life, DeSouza notes.

There are just under 70,000 Canadians are living with Parkinson’s today, according to Statistics Canada.

Successful forms of interventions or therapies include:

Physical therapy for aiding mobility, flexibility and balance;
Occupational therapy with daily activities;
Speech therapy to assist with voice control; and
Exercises that help joints and muscles, and improve the overall health and well-being of patients (Parkinson Canada).

Existing research already proved that exercising and dancing benefits those with Parkinson’s – hence, the suggested therapies, noted above – but DeSouza’s team wanted to delve deeper into the longer-term benefits of dance.

Research in this field has shifted its attention away from drug therapies to forms of interventions, such as dance, intended to improve daily functioning and quality of life.

Researchers wanted to know minimal amount of time needed to see improvements

The team decided upon a pilot study, a small-scale preliminary study executed to figure out the feasibility, time, costs etc. of doing a larger and more comprehensive study. A pilot study is intended to improve upon the design of the study before actually undertaking a full-scale research project.

Earlier research had shown motor and quality of life improvements after dance therapy at eight- and 17-months. DeSouza’s team aimed to replicate previous findings, but in a shorter time frame; his study looked at the effects of a dance program that was on average 34 per cent shorter in dance intervention duration than previous studies.

Simply put: The 91��ɫ researchers wanted to determine the minimal amount of time/intervention, the shortest dance session, needed to see improvements. “This research adds an extension to the existing literature on the required length of time necessary to see these beneficial impacts,” DeSouza explains.

DeSouza’s team wanted to determine the minimal amount of time/intervention, the shortest dance session, needed to see improvements in patients with Parkinson’s.

Nine participants from new “Dancing with Parkinson’s” Program at National Ballet

Over 12 weeks, the researchers studied nine participants with Parkinson’s who volunteered from a new Dancing with Parkinson’s Program at Canada’s National Ballet School. The participants used the “Dance for PD” model, which targets Parkinson’s -specific symptoms related to balance, cognition, motor skill, depression and physical confidence. (See table with select sample exercises.)

Table: Sample exercises featured in the dance class at National Ballet School

Exercise	Description	Purpose
Danced name introduction	Stating your name with a corresponding dance movement. The rest of the class first watches before repeating the participants name and movement. Standing or seated.	Feeling welcomed and welcoming everyone in the class. Practicing skills of choreographing on the spot.
Magic dance	Dancing with an imaginary ball and scarf, while exploring a range of motion. Seated.	An opportunity for vivid imagery and creative interpretation.
Winning the poker game	Rising slowing from a chair while moving in a celebratory manner.	Practicing rising from a seated position in a safe manner.
Shy to confident shuffle dance	A standing variation of the seated shuffle dance, where the movements are done first in a demur and small manner, but gradually increase in confidence until they are gregariously expressed.	A fun way of practicing moving with confidence and with clear intention.

The researchers gained information about the potential beneficial impacts of the dance therapy via questionnaires: Study participants completed two motor and quality of life questionnaires before and after the second and twelfth “Dance for PD” class.

To measure motor performance, the research team used the Berg Balance Scale and the Timed Up and Go test. The former is comprised of 14 tasks, measuring different everyday functions of balance and posture. Each task is rated on a scale of 0 to 4, and evaluated in terms of how long it took to complete or the quality of execution.�� The latter is a timed measurement of movement sequencing, gait and balance control. Here, a participant rises from a seated position, walks three meters, turns around, returns to the seat and sits back down.

Two quality of life questionnaires were administered, also at weeks two and 12: the Quality of Life Scale from Oregon Health and Sciences University and a post-dance class questionnaire of wellbeing developed by European researchers in this field, Olie Westheimer and Lisa Heiberger.

Results showed motor improvements in balance and gait, set stage for future research

Although no improvements were seen in terms of the study participants’ quality of life, results indicated, for the first time, motor improvements for both balance and gait in short-term (1-day) and long-term (12-weeks).

This pilot study clearly sets the stage for future research. “What remains unknown in the literature on this topic, is the specific length of dance intervention that is needed, measured in weeks and hours, until initial improvements are seen in both motor and quality of life in Parkinson’s,” says DeSouza.

He also suggests that quality of life may have already increased after just two weeks of dance class. “What is more important for future studies is to uncover the mechanisms that underlie these behavioural changes,” says DeSouza.

The article, ,” was published in Advances in Integrative Medicine (February, 2017). ��To learn more about 91��ɫ’s , visit the website. To learn more about DeSouza’s research, visit his .

To learn more about Research & Innovation at 91��ɫ, watch the , see the or visit the .

By Megan Mueller, manager, research communications, Office of the Vice-President Research & Innovation, 91��ɫ, muellerm@yorku.ca

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Scientific Director of VISTA explains discovery that may help patients with brain damage

muellerm — Fri, 06 Oct 2017 08:00:00 +0000

Doug Crawford

Canada Research Chair discovers how the brain remembers visual targets relative to other visible landmarks. This work could help those with brain damage.

Doug Crawford, scientific director of VISTA (Vision: Science to Applications), Distinguished Research Professor and the current Tier 1 Canada Research Chair in Visual-Motor Neuroscience, has devoted his career to understanding how the brain uses vision to plan movement. His work at the 91��ɫ Centre for Vision Research (CVR)�� ̶�� a global leader in this rapidly evolving field�� ̶�� has focused on the control of visual gaze in 3D space, eye-hand coordination and spatial memory during eye movements. This kind of cutting-edge research could lead to the development of devices capable of restoring vision or mobility.

"VISTA is developing technologies that will keep Canadian industry on the cutting edge while also helping people with vision-related problems. It’s the economic and health benefits of those applications that people will feel in their everyday lives."

Crawford’s latest research with former 91��ɫ graduate student Ying Chen, funded by the Canadian Institutes of Health Research (CIHR) and published in Frontiers in Systems Neuroscience (2017), suggests that targeting gaze relative to a visual landmark is different from simply gazing from memory. He sits down with Brainstorm to explain the significance and impact of this research.

Q: What were the objectives of this research, just published in Frontiers in Systems Neuroscience?

A: We were trying to determine what brain areas are active when you remember the location of an object relative to some other visual landmark, and then look that way with your eyes, as opposed to simply looking where you remember the object to be, relative to your own person. In scientific terms, this is called allocentric versus egocentric coding.

Crawford’s new research suggests that targeting gaze relative to a visual landmark is different from simply gazing from memory

Q: How did you go about conducting this research?

A: We put people inside of a magnetic resonance imaging (MRI) magnet, showed them visual stimuli in the dark and measured their eye movements. In the allocentric task, we asked people either to remember the location of a visual stimulus relative to another landmark, which we shifted before asking them to move their eyes; whereas in the egocentric task we asked them to remember where they saw it independent of the landmark.

Later, we analyzed the data to see which brain areas were activated, and which were sensitive to object location relative to the landmark.

In this research, Crawford’s team put people inside of an MRI magnet, showed them visual stimuli and measured their eye movements

Q: What did you find, and did anything surprise you about the key findings?

A: As we expected, both tasks activated areas of the brain involved in eye movements, but the allocentric task, where people used the landmark, produced more memory activation in the ventral stream of vision�� ̶�� areas running along the back and bottom of the brain. The egocentric task, where people just remembered where they saw the target, produced more dorsal stream activation at the back top of brain.

One thing we didn’t expect was that the ventral stream areas continued to be involved in coding direction during the eye movement in the allocentric task. This is something that one doesn’t ordinarily see in standard eye movement tasks.

Q: What are the implications and/or practical applications of this research?

A: One motivation for this line of research is to understand how the brain has different ways of doing things, but that this may rely on different brain areas. This is relevant for people with brain damage because it means that when one function is lost, some other brain area might replace that function.

So in this example, if brain damage affects the way people perceive or remember things using egocentric mechanisms, then these patients might train their brain to rely more on allocentric mechanisms. Knowing how these different functions relate to different brain areas can help to understand patient’s deficits and how to address them.

Brain damage affects where people perceive or remember things

Q: How would you characterize the impact of this work?

A: The immediate impact is for understanding how the brain works through fundamental, discovery science. Even though various studies have shown that fundamental science has more long-term impact than applied research, it’s often hard to predict what that impact will be.

In this case, I plan to work with some of my clinical collaborators to make sure that this work gets applied for the benefit of patients with brain damage in the coming years. But my work also gets cited by people working on biologically inspired robots. We have a lot of strength in computer vision and robotics right here at 91��ɫ, so this is something I would like to pursue as well.

“I plan to work with some of my clinical collaborators to make sure that this work gets applied for the benefit of patients with brain damage.”

Q: What does this research say about 91��ɫ’s leadership in this area?

A: 91��ɫ’s CVR has often been evaluated as one of the top vision research centres in the world. Our recent success at winning a highly competitive Canada First Research Excellence Fund (CFREF) Grant for our VISTA program signals 91��ɫ’s intend to reach the top of this list, and the Canadian government’s confidence that we can reach that goal.

The current research demonstrates our continued expansion into new areas of interdisciplinary research. We started with visual psychophysics ��̶�� behavioral tests of vision, then added in computer vision and biological recordings of brain activity. And with the purchase of a research-dedicated MRI, we’ve made our mark in functional brain imaging.

“91��ɫ’s CVR has been evaluated as one of the top vision research centres in the world. Our recent success at winning a major CFREF Grant for our VISTA program signals 91��ɫ’s intend to reach the top of this list… and the Canadian government’s confidence that we can reach that goal.”

With the new VISTA program, you can expect to see much more leadership in terms of engaging our partners in industry, hospitals and government in this research.

91��ɫ’s Centre for Vision Research is one of the top vision research centres in the world

Q: What can you say about the importance of funding this kind of research?

A: It’s important that we explain the benefits of our research to Canadians, for Canada’s wealth and well-being, because we can’t do this vital work without funding, and some of this funding will always have to come from public sources.

VISTA is involved in both fundamental and applied research, and is developing technologies that will keep Canadian industry on the cutting edge while also helping people with vision-related problems. It’s the economic and health benefits of those applications that people will feel in their everyday lives. But it’s the publicly funded fundamental research that feeds this process.

The article, “ was published in Frontiers in Systems Neuroscience (2017). To learn more about Crawford’s work, visit his , his Visuomotor Neuroscience Lab, the website or the website.

To learn more about Research & Innovation at 91��ɫ, watch the , see the or visit the .

By Megan Mueller, manager, research communications, Office of the Vice-President Research & Innovation, 91��ɫ, muellerm@yorku.ca

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Long-term exposure to microgravity impacts astronauts’ perception of upright

muellerm — Mon, 13 Feb 2017 10:00:00 +0000

Researchers at 91��ɫ’s (CVR) have discovered that astronauts who experience extended periods of microgravity experience long-term disturbances in their perception of upright.

The study “” appears this month in the . The project investigates how astronauts understand which way is up while in microgravity, and how this changes when they return to Earth.

Astronauts on the International Space Station take part in the experiments designed by the BISE Project researchers

The results represent a major finding that will have an impact on how future extended space flights are planned and implemented.

Laurence Harris

Led by Faculty of Health Professor Laurence Harris, with co-investigator Professor of the Lassonde School of Engineering, the study of astronauts’ perception of upright is the culmination of the , a multi-year project that was conducted in collaboration with the International Space Station (ISS) and sponsored by the (CSA).

“On Earth, we use visual, body and gravity information to determine our sense of orientation, which is critical to many perceptual tasks including reading, recognizing faces, and, particularly important in a space environment, navigating around and interacting with the environment,” says Harris.

On the ISS, gravity is not available and astronauts must adjust how they determine which way is up. Harris and his team measured how seven astronauts, who spent 168 days on average on the ISS, perceived their orientation before, during and after flight, and compared these results to those from a control group on earth. Remarkably, no changes were observed in the astronaut’s perception of the direction of up during their missions.

Experiencing long periods of microgravity can have a lasting impact on an astronaut’s perception of what is up

“This indicates an impressive adaptability to a microgravity environment in which the dependence on visual cues to orientation is rapidly reduced to maintain its original, on-Earth relationship to the body,” adds Harris.

The researchers discovered that a reduced emphasis on vision persisted for up to four months after the astronauts returned to Earth indicating that readjusting to gravity��may take longer than previously thought.

“The implications of this disturbance to the perception of upright could have ramifications for future missions such as those planned for Mars,” says Jenkin. The effects of long-term exposure to zero gravity could have an adverse effect the perception required to safely land on a planet.

“The disturbance in perception could impact how quickly the crew is able to function in the new gravity environment, which is critical,” says Jenkin, “given that no ground team will be available to help the astronauts readjust.”

The CVR Mission badge

Knowing “which way is up” is fundamental to our survival. On Earth, it is crucial to know where to put your feet to support your body and how to adjust to threats to this stability. In space, knowing which way is up is not needed for balance in the same way but is crucial for tasks such as knowing whether a toggle switch is in the on or off position and which way to go to get to the emergency hatch.

The findings could help with the development of countermeasures to avoid perceptual mistakes during space travel, and contribute to facilitating safer, long-duration journeys without gravity.

In addition to Harris and Jenkin, co-investigators on the study included CVR researchers Heather Jenkin, James E. Zacher and the late Richard Dyde.

Article courtesy of YFile.

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91��ɫ’s World Leading Vision Research Program Receives Canada’s Premiere Grant

muellerm — Fri, 09 Sep 2016 08:00:00 +0000

91��ɫ’s world class expertise in vision research is recognized with the nation’s top federal research funding award, the Canada First Research Excellence Fund, to the tune of $33 million.

A landmark investment in research was announced on September 8, 2016, at 91��ɫ. On this day, the government of Canada acknowledged 91��ɫ’s expertise in vision research with Canada’s most prestigious research grant. A $33.3 million (CFREF) grant will support the (VISTA) program. The investment supports research across a wide range of applications of vision science, from basic visual function, to computer vision and object recognition, and more.

Judy Sgro, Member of Parliament (MP) for��Humber River-Black Creek was joined by 91��ɫ’s Vice-President of Research and Innovation, Robert Haché, and 91��ɫ’s VISTA program scientific director, Doug Crawford, to announce the $33.3 million boost.

Left to right: Pat Clifford, Director of Research & Innovation, Southlake Regional Health Centre; Spiros Pagiatakis, Associate Dean, Research & Graduate Studies, Lassonde School of Engineering; Piotr Jasiobedzki, MDA Corporation; VISTA’s Lead PI: Doug Crawford, Faculty of Health and the Centre for Vision Research; Judy Sgro, MP, Humber River-Black Creek; Robert Haché, Vice-President Research & Innovation, 91��ɫ; Gary Brewer, Vice-President of Finance and Administration, 91��ɫ; and Paul W. McDonald, 91��ɫ’s Dean of Health. Photo credit: Jenny Pitt-Clark, YFile editor.

“The Liberal government is committed to science based policy because we know that good science informs good policy and good policy delivers positive results for all Canadians,” said MP Sgro. “Today is a real world example of what that commitment means right here at home. This funding will advance Canada's global leadership in vision research and in doing so promises long-term economic benefits for all of us.”

Judy Sgro, MP, Humber River-Black Creek. Photo credit: Lia Cavaliere, Research Events Coordinator, Office of the Vice-President Research & Innovation.

“We are delighted that the federal government has selected 91��ɫ’s VISTA project for support through the CFREF,” said Mamdouh Shoukri, President and Vice-Chancellor of 91��ɫ. “Our Centre for Vision Research is an international leader in the field, and an excellent example of the kind of innovation that can be achieved through high-level collaboration across many disciplines. This investment will allow our globally renowned researchers to continue their important work in advancing discovery in vision technologies and biological and computational vision.”

91��ɫ’s VISTA program will contribute to the next generation of industry-ready highly qualified personnel for Canada, supporting 226 additional graduate students and post-doctoral fellows.

"Today’s investment builds on 91��ɫ's existing global leadership in vision research, and will help take us to the next frontier in vision science at the interface between humans and technology,” said Haché. “This research builds on two of 91��ɫ's major intersecting pillars of research excellence - biological and computational vision - and will lead to human-centred computer vision applications that seamlessly interact with the real world to improve health, safety, productivity and quality of life."

Judy Sgro, MP, Humber River-Black Creek, and Robert Haché, Vice-President Research & Innovation, 91��ɫ. Photo credit: Lia Cavaliere, Research Events Coordinator, Office of the Vice-President Research & Innovation.

“I am thrilled by the Canadian government’s announcement of funding for 91��ɫ’s VISTA program,” said Crawford. “We have grown to rank in the top 5 in the world, and offer uniquely integrated strengths in both biological and computational vision. I look forward with great enthusiasm to reaching new heights of discovery and application for Canadian vision research.”

When fully ramped up, VISTA will include more than 50 partner organizations, 30 Canada Research Chairs and equivalents, eleven additional core faculty members, and 48 associated faculty members.�� The investments for VISTA, including 91��ɫ and partner funding will total more than $120 million.

��is known for championing new ways of thinking that drive teaching and research excellence. Through cross-discipline programming, innovative course design, diverse experiential learning and a supportive community environment, our students receive the education they need to create big ideas that make an impact on the world. Located in Toronto, 91��ɫ is the third largest university in Canada, with a strong community of 53,000 students, 7,000 faculty and administrative staff, and more than 295,000 alumni.

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91��ɫ study finds evidence for two systems of gravity perception

muellerm — Wed, 02 Mar 2016 10:00:00 +0000

How does the brain know which way is upright? How does the brain learn about the direction of gravity?

Doctoral candidate Lindsay Fraser and undergraduate honours student Bobbak Makooie

91��ɫ U researchers in the studying questions of how gravity perception works have found new evidence to suggest that this basic sensory process may be more complex than previously thought.

Though we constantly experience the force of gravity, we are seldom conscious of it, say doctoral candidate Lindsay Fraser and undergraduate honours student Bobbak Makooie, who are researching the subject under the supervision of Professor Laurence Harris.

However, say the researchers, the direction of gravity is critical to many aspects of perception and action – from keeping upright while standing, to throwing a ball and riding a bike or knowing the orientation of your own body.

Perception of gravity is often attributed exclusively to the vestibular system – a set of organs in the inner ear. This system has evolved to tell us about self-motion and head tilt relative to gravity. However, mounting evidence has suggested that the orientation of the rest of the body may be an important cue for gravity perception as well.

Fraser and Makooie recently published a set of five experiments in PLoS ONE (open source��) that capitalized on principles of sensory integration to show that gravity perception is linked not only to the sensed position of the head, but to the position of the trunk as well.

“What information your brain prioritizes depends on the question you ask,” says Fraser, the first author of this study. “Participants asked to judge gravity vertical with their hands rely more on cues from the body, while a visual task relies more on head position information.”

Normally, she says, information from both the head and body are used to get an overall sense of upright.

In the final experiment of the study, the researchers found a way to separate the two “gravity senses” by applying vibration to the muscles of the neck. They found that when the head’s position relative to the body is no longer certain, humans can no longer compare the two cues coming from body and head, and are forced to pick one or the other.

This research may help us understand how astronauts and people with balance disorders could learn to overcome vestibular challenges, by learning to rely more on gravity cues coming from the rest of the body.

The novel vibration method the researchers developed provides a potential tool for teaching people how to use all cues to gravity effectively.

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Renowned vision researcher to deliver the next Ian P. Howard Lecture

muellerm — Thu, 08 Nov 2012 10:00:00 +0000

The use of technology to simplify the early stages of visual processing is at the heart of��intriguing lecture��presented by University of California, San Diego Professor at the Ian P. Howard Lecture in Vision Science Friday.

The lecture will take place Nov. 9 at 2pm in the Robert McEwen Auditorium, W141 Seymour Schulich Building, Keele campus. A��reception will follow the talk.

Brains need to make quick sense of massive amounts of ambiguous information with minimal energy costs and have evolved an intriguing mixture of analog and digital mechanisms to allow this efficiency. Analog electrical and biochemical signals inside neurons are used for integrating synaptic inputs from other neurons. The digital part is the all-or-none action potential, or spike, that lasts for a millisecond or less and is used to send messages over a long distance.

Terry Sejnowski

"Spike coincidences occur when neurons fire together at nearly the same time," says Sejnowski. "In this lecture I will show how rare spike coincidences can be used efficiently to represent important visual events and how this architecture can be implemented with analog Very Large Scale Integration (VLSI) technology to simplify the early stages of visual processing."

Sejnowski is professor and laboratory head of the Computational Neurobiology laboratory.��He is considered to be��a pioneer in computational neuroscience and his goal is to understand the principles that link brain to behavior. His laboratory uses both experimental and modeling techniques to study the biophysical properties of synapses and neurons and the population dynamics of large networks of neurons.

Among other things, Sejnowski is interested in the hippocampus, believed to play a major role in learning and memory; and the cerebral cortex, which holds our knowledge of the world and how to interact with it. In his lab, Sejnowski's team uses sophisticated electrical and chemical monitoring techniques to measure changes that occur in the connections among nerve cells in the hippocampus during a simple form of learning. They use the results of these studies to instruct large-scale computers to mimic how these nerve cells work. By studying how the resulting computer simulations can perform operations that resemble the activities of the hippocampus, Sejnowski hopes to gain new knowledge of how the human brain is capable of learning and storing memories. This knowledge ultimately may provide medical specialists with critical clues to combating Alzheimer's disease and other disorders that rob people of the critical ability to remember faces, names, places and events.

Sejnowski has published more than 300 scientific papers and 12 books, including The Computational Brain (1992), with Patricia Churchland.��He��received his PhD in physics from Princeton University and was a postdoctoral fellow at Harvard Medical School. He was on the faculty at the Johns Hopkins University and now holds the Francis Crick Chair at The Salk Institute for Biological Studies. He��is a professor of biology at the University of California, San Diego, where he is co-director of the Institute for Neural Computation and co-director of the National Science Foundation (NSF)��.��Sejnowski is the president of the Neural Information Processing Systems (NIPS) Foundation, which organizes an annual conference attended by over 1000 researchers in machine learning and neural computation and is the founding editor-in-chief of Neural Computation published by the MIT Press.

An investigator with the , he is also a Fellow of the American Association for the Advancement of Science and a Fellow of the Institute of Electrical and Electronics Engineers. He has received many honors, including the NSF Young Investigators Award, the Wright Prize for interdisciplinary research from the Harvey Mudd College, the Neural Network Pioneer Award from the Institute of Electricaland Electronics Engineers and the Hebb Prize from the International Neural Network Society.

Sejnowski was��elected to the Institute of Medicine in 2008, to the National Academy of Sciences in 2010 and to the National Academy of Engineering in 2011. He is one of only 10 living persons to be a member of all��three national academies.

The Ian P. Howard Lecture Series in Vision Science��provides a venue for world-renowned vision researchers to deliver lectures on their findings.

The series was established in 2006 to celebrate Howard’s enormous contributions to the international reputation of��91��ɫ's Centre for Vision Research. Howard’s own research investigates the fundamental mechanisms that enable humans to orient themselves and perceive the three-dimensional layout of their surroundings.

For further information, contact Teresa Manini, administrative assistant, Centre for Vision Research, at manini@cvr.yorku.ca.

Republished courtesy of YFile– 91��ɫ’s daily e-bulletin to research stories on the research website.

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Toronto Star covers inaugural 3D film conference led by 91��ɫ researchers

fmaquito — Mon, 13 Jun 2011 08:00:00 +0000

And as the film world continues its rapid transition from traditional 2 D celluloid film to 3 D digital, a weekend conference at the TIFF Bell Lightbox is aimed at boosting the Toronto film community’s chances of capitalizing on the next wave in film – 3-D, wrote the :

The [] conference is co-sponsored by 91��ɫ’s Faculty of Fine Arts and the 3-D Film Innovation Consortium (3D FLIC), a group of GTA-based film companies.

Ali Kazimi, professor in the University’s film department, said the three-day event will bring together an “eclectic mix” of filmmakers, artists, academics and theorists. “It’s a truly interdisciplinary event. We believe it’s not just a first in Canada, we believe it’s the first time anywhere in the world that these...fairly disparate groups of people have been brought together to discuss the future of 3-D cinema,” Kazimi said.

“I think this is going to be a very special event for the city. Our project has really put Toronto on the map because with this incredible sharing of knowledge,” he added.

Until the debut of Avatar in December, 2009, there was little interest in 3-D as a new frontier in film, Kazimi said. “Now everybody is jumping on the bandwagon. As a filmmaker, I feel it’s a very exciting time because when used properly, 3-D offers a whole new language for filmmakers,” Kazimi said.

The conference and 3D FLIC also involve psychology and computer science researchers within the . The centre's conference on runs June 15-18, allowing researchers to attend both events.

For more background on the Toronto International Stereoscopic 3D Conference, see its or this .

Posted by Elizabeth Monier-Williams, research communications officer, with files courtesy of YFile– 91��ɫ’s daily e-bulletin.

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