We do it without thinking. If we see an object in front of us, but then turn our eyes and body left to look down the street, our mind remembers the image of the pathway and pole and moves it appropriately across a short-term visual memory map so we instinctively know it is now 90 degrees to the right of our eyes, even though we are no longer looking at it.
Photo Credit: CBC

Canadian research discovers how we continually update visual memory of surroundings.

It’s something we do without ever thinking about it. It’s a short-term “visual memory map” of where things are in relation to our bodies and where we are currently looking, even as we shift our vision and bodies away from the object.

It’s a groundbreaking study, and an important step in understanding how our brains work. The study was supervised by Doug Crawford (PhD). He is the Canadian Director, Brain in Action IRTG, Canada Research Chair in Visuomotor Neuroscience, Distinguished Research Professor in Neuroscience in the Faculty of Health, and is a member of the York University Centre for Vision Research in Toronto Ontario.

Listen
null
Doug Crawford PhD-Canada Research Chair in Visuomotor Neuroscience, Distinguished Research Professor in Neuroscience © York University

The study published in the latest edition of the online science journal Current Biology-Cell,  has a complex title,  Continuous Updating of Visuospatial Memory in Superior Colliculus during Slow Eye Movements

What Professor Crawford’s team discovered was that the brain has visual short-term “map” which is constantly being overwritten as we move or look around.

Professor Crawford cites the case of a football quarterback who quickly sees an alternative receiver 4 metres and at about 80 degrees to his right but then looks downfield for a long distance catcher. He spots one and tracks him with his eyes, but then he is threatened with being tackled before he can make the long pass. Fortunately, his visual memory also kept track of where the alternative receiver is even before he turns to see him, giving him that extra few milliseconds to prepare the throw to the right location.

null
Remembered visual location is continuously ‘updated’ in a midbrain visual map called the superior colliculus (SC). In this case, if your eyes follow the player moving to the left while you try to remember the player on the right, a ‘hill’ of memory-related activity moves in the left SC (because visual space is reversed in the brain). © supplied York U

The York research team found this visual mapping located in an ancient area of our brain development called the midbrain superior colliculus.

“As the eyes move, activity related to the remembered target travels across the ‘visual’ cells in the midbrain superior colliculus, constantly keeping track of its location relative to the direction the eyes are currently pointed,” explains Professor  Crawford,  “In our football example, when it’s time to aim an eye movement and then make a pass toward the open receiver, the visual memory is transferred to motor cells which then produce a burst of activity.”

null
Professor Crawford stands beside state of the art fMRI scanner, modified with addtional equipment for use in certain brain function related research at York University, Faculty of Health © York U

The research, led by postdoctoral fellow Suryadeep Dash, also suggests that continuous updating of signals could emerge in other visuomotor areas of the brain.

Professor Crawford says, “Studying this system might help us understand how we remember where things are during other continuous motion behaviors such as walking, driving or general navigation.”

He notes there may also be clinical implications in understanding some disorders like schizophrenia, where patients may have trouble distinguishing between real events and internal events in their brain, whether they are thoughts or the movement plans used to keep track of visual memory. Degradation of these visual memory processes might also explain some aspects of senile dementia, where both spatial memory and navigation are affected.

York U- visuomotor neuroscience Lab

Tagged with: , ,
Posted in Health, Science and Technology

Do you want to report an error or a typo? Click here!

@*@ Comments

Leave a Reply

Your email address will not be published. Required fields are marked *

 characters available

Note: By submitting your comments, you acknowledge that Radio Canada International has the right to reproduce, broadcast and publicize those comments or any part thereof in any manner whatsoever. Radio Canada International does not endorse any of the views posted. Your comments will be pre-moderated and published if they meet netiquette guidelines.

Netiquette »

When you express your personal opinion in an online forum, you must be as courteous as if you were speaking with someone face-to-face. Insults and personal attacks will not be tolerated. To disagree with an opinion, an idea or an event is one thing, but to show disrespect for other people is quite another. Great minds don’t always think alike—and that’s precisely what makes online dialogue so interesting and valuable.

Netiquette is the set of rules of conduct governing how you should behave when communicating via the Internet. Before you post a message to a blog or forum, it’s important to read and understand these rules. Otherwise, you may be banned from posting.

  1. RCInet.ca’s online forums are not anonymous. Users must register, and give their full name and place of residence, which are displayed alongside each of their comments. RCInet.ca reserves the right not to publish comments if there is any doubt as to the identity of their author.
  2. Assuming the identity of another person with intent to mislead or cause harm is a serious infraction that may result in the offender being banned.
  3. RCInet.ca’s online forums are open to everyone, without regard to age, ethnic origin, religion, gender or sexual orientation.
  4. Comments that are defamatory, hateful, racist, xenophobic, sexist, or that disparage an ethnic origin, religious affiliation or age group will not be published.
  5. In online speak, writing in ALL CAPS is considered yelling, and may be interpreted as aggressive behaviour, which is unpleasant for the people reading. Any message containing one or more words in all caps (except for initialisms and acronyms) will be rejected, as will any message containing one or more words in bold, italic or underlined characters.
  6. Use of vulgar, obscene or objectionable language is prohibited. Forums are public places and your comments could offend some users. People who use inappropriate language will be banned.
  7. Mutual respect is essential among users. Insulting, threatening or harassing another user is prohibited. You can express your disagreement with an idea without attacking anyone.
  8. Exchanging arguments and opposing views is a key component of healthy debate, but it should not turn into a dialogue or private discussion between two users who address each other without regard for the other participants. Messages of this type will not be posted.
  9. Radio Canada International publishes contents in five languages. The language used in the forums has to be the same as the contents we publish. The usage of other languages, with the exception of some words, is forbidden. Messages that are off-topic will not be published.
  10. Making repetitive posts disrupts the flow of discussions and will not be tolerated.
  11. Adding images or any other type of file to comments is forbidden. Including hyperlinks to other websites is allowed, as long as they comply with netiquette. Radio Canada International  is in no way responsible for the content of such sites, however.
  12. Copying and pasting text written by someone else, even if you credit the author, is unacceptable if that text makes up the majority of your comment.
  13. Posting any type of advertising or call to action, in any form, to Radio Canada International  forums is prohibited.
  14. All comments and other types of content are moderated before publication. Radio Canada International  reserves the right to refuse any comment for publication.
  15. Radio Canada International  reserves the right to close a forum at any time, without notice.
  16. Radio Canada International  reserves the right to amend this code of conduct (netiquette) at any time, without notice.
  17. By participating in its online forums, you allow Radio Canada International to publish your comments on the web for an indefinite time. This also implies that these messages will be indexed by Internet search engines.
  18. Radio Canada International has no obligation to remove your messages from the web if one day you request it. We invite you to carefully consider your comments and the consequences of their posting.

*