The findings bear out stories from vets who have described blind dogs acting completely normally – playing fetch and not bumping into things.
A team of vets, including Dr Philippa Johnson from Cornell University in New York, discovered that vision and smell are actually connected in the brains of dogs – something not yet found in any other species.
The team conducted MRI scans on a number of different dogs and successfully mapped the olfactory bulb (the part of the brain dealing with smell) to the occipital lobe (the visual processing area of the brain), shedding new light on how dogs experience and navigate the world.
It revealed an “extensive pathway” connecting to the occipital lobe but also to the limbic system, which is the part of the brain involved in behavioural and emotional responses.
The findings, published in the Journal of Neuroscience, suggest smell and vision in dogs are therefore integrated in some way – implying they may use scent to work out where things are.
Dr Johnson told Sky News that when humans walk into a room, they primarily use their sense of vision to establish who is there or how furniture is positioned. But dogs seem to integrate scent into their interpretation of their environment and how they are orientated in it.
She added: “One of the ophthalmologists at the hospital here said he regularly has owners that bring their dogs in, and when he tests their eyesight, they are completely blind – but the owners literally won’t believe him.
“The blind dogs act completely normally. They can play fetch. They can orientate around their environment, and they don’t bump into things.
“Knowing there’s that information freeway going between those two areas, could be hugely comforting to owners of dogs with incurable eye diseases.”
“We’ve never seen this connection between the nose and the occipital lobe, functionally the visual cortex in dogs, in any species,” added Dr Johnson, assistant professor of clinical sciences at Cornell, and senior author of the report.
In the course of their study, the team also found connections where a dog’s brain processes memory and emotion, which are similar to those in humans.