Blog dedicated primarily to randomly selected news items; comments reflecting personal perceptions

Friday, June 15, 2018

Unveiling the Brain's Mysterious Ways

"I realized I was blind."
"It's almost as if everything is under water, and it's all fuzzy and hazy."
"Am I ever going to get even a little bit back [eyesight] in one eye so that I can at least see my family and friends? I hope it keeps on improving. But this might be it. Nobody knows."
"I can’t see like normal people see or like I used to see. The things I’m seeing are really strange. There is something happening and my brain is trying to rewire itself or trying different pathways."
Milena Canning, 48, Scotland
"And that particular piece of tissue [intact in the patient's occipital lobes] is an area that responds vigorously in everybody -- in her, in you and me -- to things that are moving."
"This may be the richest characterization ever conducted of a single patient's visual system. She has shown this very profound recovery of vision, based on her perception of motion."
"She is missing a piece of brain tissue about the size of an apple at the back of her brain – almost her entire occipital lobes, which process vision."
"In Milena’s case, we think the ‘super-highway’ for the visual system reached a dead end. But rather than shutting down her whole visual system, she developed some ‘back roads’ that could bypass the superhighway to bring some vision – especially motion – to other parts of the brain."
"Patients like Milena give us a sense of what is possible and, even more importantly, they give us a sense of what visual and cognitive functions go together."
"It’s important for patients and physicians to realize vision isn’t necessarily an all-or-nothing thing. It’s not that someone is blind or sighted and there’s nothing in between."
Dr. Jody Culham, neuro-psychologist, professor, Department of Psychology and Graduate Program in Neuroscience,Western University, London, Ontario

In 1999, Milena Canning of Glasgow, contracted a lung infection which led to severe respiratory collapse. Severe enough that her organs began to fail, and doctors placed her in a coma induced by drugs for a 52-day period. While still in that coma she suffered a stroke, perhaps more than one. Finally she awoke to the realization that she no longer had vision, due to damage of her brain tissue. Surgery followed to clear away the dead brain tissue, leaving large, dark vacuums. They appear as black holes on brain scans.

Her condition while rare is not entirely unique. It is a phenomenon known as Ridoch syndrome, first described, ironically enough in 1917 by Scottish neurologist George Ridoch. Five of his patients had presented with injured occipital lobes -- located at the back of the brain where most visual information is processed. They informed Dr. Ridoch they could see nothing that was stationary, but were able to see anything that moved.

Milena Canning had residual tissue that remained functional despite the horrible damage to her occipital lobes; a tiny piece of tissue, teaspoon-sized, that remained intact in both hemispheres. She is a patient of two Western University scientists who have tested her eyesight for years, validating that she can 'see objects' while they are in motion; swirling bathwater, wind blowing clothing on a clothesline or the movement of clothing in a laundry clothes drier, dangling foliage blown by the wind.

That tiny amount of residual tissue enables her to see steam rising from a kettle, her daughter Stephanie's ponytail swinging as she moves briskly along; not clear and concisely, but notionally and occasionally with a colour background of something appearing wet and shiny like a forest landscape after a heavy downpour. Like an impressionist landscape, not detailed or with any kind of perspective.

She had been referred to the Brain and Mind Institute at Western University back in 2007. Her peculiar vision has undergone a number of tests there over the years and formed a test study whose conclusions were reported for publication in the journal Neuropsychologia. Present-day advanced technology has led to sophisticated brain imaging techniques to allow scientists an improved understanding of the involvement of neural circuits.

This woman living with severely limited eyesight proved capable of catching balls in experiments where the balls were rolled or thrown at her. She was able to identify rainwater running down a windowpane. The team reported on her "remarkably robust preserved ability to perceive motions". As limited as is her ability to see stationary objects, she remains optimistic that she may one day recover more of her lost vision.

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