Using a classic visual illusion, 91��ɫ researchers identify a history-dependent computation present in primate vision that current AI models fail to reproduce.

TORONTO, Oct. 2, 2026 – Our eyes do not always tell us exactly where things are – and that may be a feature of how biological vision works, rather than simply a flaw. A new study by 91��ɫ researchers uses a common illusion to ask if artificial intelligence is meant to see more like us, should it make some of the same systematic perceptual “mistakes”?

For example, after staring at something moving steadily in one direction, a stationary object viewed immediately afterward can appear slightly displaced in the opposite direction. This well-known visual illusion, called a motion aftereffect, gives scientists an unusual window into the computations underlying perception: the image itself has not moved, but our experience of where it is has changed.

“Today’s AI vision systems are impressive, but they still do not always see the world the way we do. This study captures the promise of NeuroAI and what it can do when neuroscience and artificial intelligence are brought together. By using smart experiments to reveal the computations biological vision uses and AI still lacks, we can use those insights to build better, more brain-like artificial systems,” says senior author 91��ɫ Assistant Professor Kohitij Kar, the Canada Research Chair in Visual Neuroscience and a member of 91��ɫ’s Centre for Vision Research and Centre for Integrative and Applied Neuroscience.

Current AI vision systems can often determine where an object is accurately, but they generally do not reproduce the way recent visual experience can reshape that answer. In humans, staring at motion can make a subsequently viewed stationary object appear displaced even though its pixels have not moved. The researchers found a corresponding change in the primate visual cortex – but not in the AI models they tested.

To gain better insight into the issue, the researchers examined whether artificial neural network models capture the same history-dependent changes in spatial representations seen in biological vision, or whether their position representations primarily reflect the physical properties of the image. The researchers, including the paper’s first author and 91��ɫ graduate student Elizaveta Yakubovskaya, used precise measurements to find out where AI differs from biological vision and how that gap could be bridged.

“Combining recordings from primate visual cortex with human perception experiments, we used motion adaptation to induce a visual illusion and make a stationary object appear slightly shifted in position, then asked whether the brain and AI showed the same effect. Human observers reported the illusion, and neural representations of position in the primate inferior temporal (IT) cortex shifted in the same direction, even though the image itself had not changed,” says Yakubovskaya.

The researchers leveraged motion adaptation to show where perceived and pixel-based positions diverge, allowing them to test the behavioral relevance of IT codes. The findings not only further our understanding of IT’s role in spatial information encoding but provide a new benchmark to evaluate dynamic vision models.

“There is a growing question in AI about whether increasingly capable systems will become more like us or increasingly different from us,” says Kar of the Faculty of Science and a member of the 91��ɫ-led Connected Minds. “If we want AI that works with humans and understands the world in more human-compatible ways, we cannot focus only on whether it gets the right answer. We also need to understand the computations that produce human perception and behavior. Neuroscience gives us a way to discover those computations and, potentially, build them into AI,” adds Kar.

The study titled, , is published today in Current Biology.

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Study first to show improvements in both self-reported questionnaires and MRI brain scans

TORONTO, Dec. 13, 2024 – Dancing lowers the depression associated with Parkinson disease, and the benefits can be seen in multiple ways, published in the Journal of Medical Internet Research involving 91��ɫ researchers shows. 

“It was very cool to see that dance had a positive effect on the mood circuits in the brain, which we could see in the imaging,” says Faculty of Health associate professor , an author of the study. “These improvements that we could see on MRI brain scans were also reported by the participants via survey. Our study is the first to demonstrate these benefits across these two detection methods.” 

The study, published today, followed 23 participants in the Sharing Dance Parkinson’s program at Canada’s National Ballet School who had a diagnosis of Parkinson disease, as well as 11 healthy controls, who were mostly family members or caretakers of those with Parkinson disease. The participants took weekly dance classes for 8 months, which progressed from simple leg and foot work and pliés to interpretive movements, waltzes, and more complicated, choreographed dances. 

The researchers include DeSouza; former 91��ɫ PhD student Karolina Bearss, now a professor at Algoma University; former 91��ɫ PhD student Rebecca Barnstaple, now assistant professor of Creative Arts, Health and Wellness, cross-appointed with Theatre at the University of Guelph; and Rachel Bar, a former 91��ɫ undergraduate student who is now director of research and health at Canada’s National Ballet School. They honed in on a node in the brain, the subcallosal cingulate gyrus (SCG), that has been shown in previous research to be implicated in depression. They measured mood and depression scores in all participants using the Geriatric Depression Scale before and after every class and conducted regular MRI scans at 91��ɫ. 

The researchers found that after each dance class, reported depression rates dropped, and the effect was cumulative from class to class, with significant improvements after 8 months. They also found that the MRI scans showed reduced signals in a frontal-cortex brain region associated with emotional regulation and that in a smaller subset of the participants, a significant decrease in depression scores was correlated with changes in the SCG node. 

“We essentially showed that SCG BOLD [blood oxygen level–dependent] signal decreases while dancing over time. Which means that the SCG was not functioning as fast as it would if you had depression," says Bearss. 

Parkinson disease is a progressive neurodegenerative disease. Before diagnosis, there is a prodromal phase that can last 2 to 10 years and is characterized by low mood, even before other symptoms appear, such as tremors and other issues with motor control. 

“People with Parkinson's disease tend to have multiple symptoms that are not just motor related, there are a lot of symptoms that include mental and social well-being impairments, one of those being depression,” explains Bearss. 

This research builds on Bearss and DeSouza’s that found that dance training helps people with Parkinson disease with motor control, mood, and other functions of daily living. 

Dance is thought to have a double benefit, with music activating the brain’s reward centers, and the movement acting on sensory and motor circuits. DeSouza, who has been dancing with participants in the program for 14 years, says that while dancing is not a treatment for Parkinson disease per se, the benefits are clear. 

“We're not trying to cure Parkinson's with dance,” says DeSouza, also with the Centre for Vision Research and Connected Minds at 91��ɫ. “What we're trying to do is to have people live a better quality of life. This goes for both those with the disease, and their families that take care of them — they also get benefits of feeling better.” 

The study, “Impact of Weekly Community-Based Dance Training Over 8 Months on Depression and Blood Oxygen Level–Dependent Signals in the Subcallosal Cingulate Gyrus for People With Parkinson Disease: Observational Study,” was published today in the open-access Journal of Medical Internet Research.

Original article:

Bearss KA, Barnstaple R, Bar R, DeSouza JFX. Impact of Weekly Community-Based Dance Training Over 8 Months on Depression and Blood Oxygen Level–Dependent Signals in the Subcallosal Cingulate Gyrus for People With Parkinson Disease: Observational Study. JMIRx Med 2024;5:e44426

URL: https://med.jmirx.org/2024/1/e44426/

doi: 10.2196/44426

PMID:

About 91��ɫ:

91��ɫ is a modern, multi-campus, urban university located in Toronto, Ontario. Backed by a diverse group of students, faculty, staff, alumni and partners, we bring a uniquely global perspective to help solve societal challenges, drive positive change, and prepare our students for success. 91��ɫ's fully bilingual Glendon Campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education. 91��ɫ’s campuses in Costa Rica and India offer students exceptional transnational learning opportunities and innovative programs. Together, we can make things right for our communities, our planet, and our future.

Media Contact: Emina Gamulin, 91��ɫ Media Relations, 437-217-6362, egamulin@yorku.ca

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91��ɫ-led findings show astronauts can safely assess distances in weightless environment

TORONTO, March 25 2024 – New research led by 91��ɫ finds .

The findings of the study, done in collaboration with the Canadian Space Agency and NASA, have implications for crew safety in space and could potentially give clues to how aging affects people’s balance systems here on Earth, says the study’s lead Faculty of Health Professor .

“It has been repeatedly shown that the perception of gravity influences perceptual skill. The most profound way of looking at the influence of gravity is to take it away, which is why we took our research into space,” says Harris, an expert on vision and the perception of motion who also heads up the Multisensory Integration Lab and is the former director of the at 91��ɫ.

“We’ve had a steady presence for close to a quarter century in space and with space efforts only increasing as we plan to go back to the moon and beyond, answering health-and-safety questions only becomes more important. Based on our findings it seems as though humans are surprisingly able to compensate adequately for the lack of an Earth-normal environment using vision.”

Harris and collaborators – who include Lassonde School of Engineering professors Robert Allison and Michael Jenkin, and two generations of 91��ɫ post docs and graduate students Björn Jörges, Nils Bury, Meaghan McManus and Ambika Bansal – studied a dozen astronauts aboard the International Space Station, which orbits about 400 kilometres from the Earth’s surface. Here, Earth's gravity is approximately cancelled out by centrifugal force generated by the orbiting of the station. In the resulting microgravity, the way people move is more like flying, says Harris.

“People have previously anecdotally reported that they felt they were moving faster or further than they really were in space, so this provided some motivation to actually record this,” he explains.

The researchers compared the performance of a dozen astronauts – six men and six women – before, during, and after their year-long missions to the space station and found that their sense of how far they travelled remained largely intact.

Space missions are busy endeavours and it took the researchers several days to connect with the astronauts once they arrived at the space station. Harris says that it’s possible their research was unable to capture early adaptation that may have occurred in those first few days, “it's still a good news message because it says that whatever adaptation happens, happens very quickly.”

Space missions are not without risk. As the ISS orbits the Earth it is sometimes hit with small objects that could penetrate the vessel requiring astronauts to move to safety.

“On a number of occasions during our experiment, the ISS had to perform evasive maneuvers,” recalls Harris. “Astronauts need to be able to go to safe places or escape hatches on the ISS quickly and efficiently in an emergency. So, it was very reassuring to find that they were actually able to do this quite precisely.”

The study, published recently in npj Microgravity, has been a decade in the making, and represents the first of three papers that will emerge from the research investigating the effects of microgravity exposure on different perceptual skills including the estimation of body tilt, travelled distance, and object size.

Harris says research shows exposure to microgravity mimics the aging process on a largely physiological level  – wasting of bones and muscles, changes in hormonal functioning and increased susceptibility to infection  – but this paper finds that self-motion is largely unaffected, suggesting the balance issues that frequently come from old age may not be related to the vestibular system.

“It suggests that the mechanism for the perception of movement in older people should be relatively unaffected, and that the issues involved in falling may not be so much in terms of the perception of how far they've moved, but perhaps more to do with how they're able to convert that into a balance reflex.”

About 91��ɫ

91��ɫ is a modern, multi-campus, urban university located in Toronto, Ontario. Backed by a diverse group of students, faculty, staff, alumni and partners, we bring a uniquely global perspective to help solve societal challenges, drive positive change, and prepare our students for success. 91��ɫ’s fully bilingual Glendon Campus is home to Southern Ontario’s Centre of Excellence for French Language and Bilingual Postsecondary Education. 91��ɫ’s campuses in Costa Rica and India offer students exceptional transnational learning opportunities and innovative programs. Together, we can make things right for our communities, our planet, and our future.

Media Contacts: Emina Gamulin, 91��ɫ Media Relations and External Communications, 437-217-6362, egamulin@yorku.ca

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TORONTO, April 25, 2017– An international research collaboration between Canada and Japan with 91��ɫ Faculty of Health’s Professor Laurence Harris has discovered that our perception of self-motion has a previously unknown safety feature. Their discovery involves tactile flow, the tactile stimulation provided as you push through leaves in the undergrowth or rub your hands along a wall, and its predominant role in enhancing our sense of self-motion, overriding the information provided by vision and the balance-and-movement system contained within the inner ear.

“When you move around you have visual information that tells you how you’re moving and when you walk around the information flows past you”, says Harris. “If you’re touching something stationary as you move, such as a wall or the bannisters then that information, that tactile information, will also flow over your skin."

Harris, who is the director of the Centre for Vision Research at 91��ɫ, was invited to the Tohoku Gakuin University (TKU) in Sendai, Japan. There he collaborated with TKU Professor Kenzo Sakurai and researcher William Beaudot. “It was very unexpected,” says Harris. “Instead of simply combining with other sensory information about the movement in the same way as for example visual and acceleration cues combine, tactile flow actually dominated perceived self-motion."  The addition of tactile information seems to provide a sort of emergency override, says Harris, making people feel they are going faster than they really are –something he says that may contribute to the "thrill of sliding down the banisters".

In their experiments they measured the perception of self-motion; how fast a person was going and how the perceived timing of the motion was impacted by the addition of tactile flow. Harris adds that there are special receptors in skin that are specialized to respond to something moving over the skin.

“We had people sitting on a swing that could move from side to side. Participants rested their fingertips on a flat piece of wood that was stationary. As they moved from side to side, they could feel the motion on their fingertips,” says Harris. “We discovered that this made them feel they were moving faster than when they were not feeling the tactile flow at the same time.”

The importance of this newly discovered role of touch in our sense of self-motion may account for why we reach for something to stabilize ourselves to prevent a fall if we miss a step. Holding on to something provides stability and provides a tactile cue about what is happening, overriding other available cues. The discovery also has ramifications for designing systems to provide artificial tactile cues to motion to enhance the experience of virtual reality or to help pilots monitor the movement of their aircraft.

“Artificial tactile stimulation might be a powerful aid to provide self-motion information in virtual environments or in situations where accurate knowledge about self-motion is critical, such as when flying a high-performance plane,” says Harris. “In people who are at risk of balance problems, such as older or blind individuals, or people who have had damage to the vestibular system, this information could provide an additional motion cue for them to help create tools for them.”

The researchers used TKU’s parallel swing, a specialized apparatus that moves a person from side to side. In their study, they had test subjects swing with and without tactile clues (created by running finger tips along a stationary surface).
The research Tactile flow overrides other cues to self-motion appears in the journal Scientific Reports and appears on nature.com.

Watch Prof. Laurence explain the findings here in this video:

91��ɫ is known for championing new ways of thinking that drive teaching and research excellence. Our students receive the education they need to create big ideas that make an impact on the world. Meaningful and sometimes unexpected careers result from cross-discipline programming, innovative course design and diverse experiential learning opportunities. 91��ɫ students and graduates push limits, achieve goals and find solutions to the world’s most pressing social challenges, empowered by a strong community that opens minds. 91��ɫ U is an internationally recognized research university – our 11 faculties and 26 research centres have partnerships with 200+ leading universities worldwide. 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. 91��ɫ U's fully bilingual Glendon campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education.

Media Contacts:
Anjum Nayyar, 91��ɫ Media Relations, 416-736-2100 ext. 44543 anayyar@yorku.ca

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TORONTO, Nov. 16, 2016 – Are you ready to tumble? 91��ɫ’s Centre for Vision Research has three new pieces of equipment to study how motion and gravity affects perception, which could have implications for astronauts and regular people alike. Media will be able to try out the equipment at an interactive technical briefing and open house Wednesday morning.

Take a tumble in the tumbling room. Can you tell which way is up or down in a room that can spin 360 degrees? Have a seat in the suspended chair and rotate 360 degrees either with the room or separately, and see if you know whether it was the room or the chair that moved.

“The equipment is used to help determine how perception and movement work together and that can have implications for the elderly and for astronauts navigating in space,” says , director of 91��ɫ U’s Centre for Vision Research.

Psychology Professor Laurence Harris, director of 91��ɫ's Centre for Vision Research, takes a spin in the new tumbling room

91��ɫ U Professor Laurence Harris taking the chair in the tumbling room for a spin

The second new piece is the Edgeless Graphics Geometry 3D stereoscopic visualization system. It includes a screen that takes in the whole of a person’s peripheral vision, 110 degrees on either side, and displays a scene or a sequence of tunnels to test how people move in space and what they perceive, while sitting or standing.

The third piece is the sphere. It’s similar to the tumbling room, but instead of right-side up animal print wallpaper, its interior is covered in different sized dots so that when it stops it’s even harder to know your position relative to gravity. This last piece can be viewed and tried after the first two pieces for those who can stay a little longer as it’s in a different building.

Funding for the equipment came from a . The tumbling room and sphere were both built by Dymech Engineering Inc., while the Edgeless Graphics Geometry system was built by Christie Digital Systems USA, Inc.

SPACE IS LIMITED.

Please RSVP if you’re interested in learning more about the equipment and, of course, going for a spin. A GoPro or cell phone can be attached to the wall of the tumbling room for those interested in taking video while going round and round.

WHAT: Media technical briefing and open house for new equipment

WHEN: Wednesday, Nov. 23, from 10am to noon

WHERE: 91��ɫ, Keele campus, 4700 Keele St., Toronto, ON M3J 1P3

-30-

 is known for championing new ways of thinking that drive teaching and research excellence. Our students receive the education they need to create big ideas that make an impact on the world. Meaningful and sometimes unexpected careers result from cross-discipline programming, innovative course design and diverse experiential learning opportunities. 91��ɫ students and graduates push limits, achieve goals and find solutions to the world’s most pressing social challenges, empowered by a strong community that opens minds. 91��ɫ U is an internationally recognized research university – our 11 faculties and 26 research centres have partnerships with 200+ leading universities worldwide. 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. 91��ɫ U's fully bilingual Glendon campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education.

Media Contact:

Sandra McLean, 91��ɫ Media Relations, 416-736-2100 ext. 22097, sandramc@yorku.ca

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