Curious Kids: if our eyes see upside down, how does the brain flip the picture?

Daniel Joyce, University of Southern Queensland

I heard that we see upside down, but our brain flips the image. How does it do that?

–Jasmine, Mount Evelyn, Victoria

Our eyes work thanks to light. Objects we can see are either sources of light themselves – like a candle or a phone screen – or light bounces off them and makes its way to our eyes.

First, light passes through the optical components of the eyes such as the cornea, pupil and lens.

Together, they help focus the light onto the retina that senses light, while also controlling the intensity of light to help us see well while avoiding damage to the eye.

The function of the lens is to correctly focus light that comes from objects at different distances. This process is known as accommodation.

While performing this important task, light passing through the lens becomes inverted. This means that light from the top of the object falls lower on the retina than light from the bottom, which falls higher on the retina.

So, light exiting the lens to land on the retina is indeed flipped upside down. But that doesn’t mean the brain is actually flipping the picture “back”. Here’s why.

The orientation doesn’t actually matter

While the light being interpreted by the brain is “upside down” compared to the real world, the question is: is that actually a problem for us?

From your own experience you can tell the answer is probably no. We seem to navigate and interact with the world just fine.

So, where in the brain is the image flipped or rotated 180 degrees to be the “right way up” again?

You may be surprised to learn that vision scientists reject the idea a flipping or rotation needs to happen at all. This is because of how our brains process visual information.

The object you perceive is “encoded” by the firing of various neurons – brain cells that process information – in various locations in the brain. This pattern of firing is what encodes the information about the object you’re focusing on. That info takes into account the object’s relation to everything else in the scene, your body in the world, and your movements.

As long as the relative encodings of these are all consistent with one another, as well as stable, there’s no need for a flip to happen at all.

We can function with ‘upside down’ goggles!

Several studies have looked at how we adapt to large changes in visual input by asking people to wear goggles that flip the image coming in.

This means the image lands on the retina the “right way up”, so to speak, but upside down from what the brain has learned it should be.

In the 1930s, two scientists in Austria performed the Innsbruck Goggle Experiments. For weeks or even months at a time, participants in these studies wore goggles that altered the way the world around them looked. This included goggles that turn the incoming image upside down.

 

A person blinks while wearing an ‘invertoscope’ – goggles that turn the incoming image upside down. Dmitry Hoh/Wikimedia Commons, CC BY-SA

As you can imagine, people wearing these goggles at first found it really difficult to get by in their day-to-day activities. They would stumble and bump into things.

But this was temporary.

Participants reported seeing the world upside-down for the first few days, with difficulties navigating the environment, including trying to step over ceiling lights that appeared to them as on the floor.

Around the fifth day, however, performance seemed to improve. Things that were at first seen upside down now appeared the right way up, and this tended to improve with more time.

In other words, with continued exposure to the upside-down world, the brain adapted to the changed input.

More recent studies are beginning to identify which areas of the brain are involved in being able to adapt to changes in visual input, and what the limits of our ability to adapt might be.

Adaptation may even allow “colour blind” people to see colour better than is predicted from their condition.

Daniel Joyce, Senior Lecturer in Psychology, University of Southern Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More........→May 12, 2026

Successful World First: Baby Treated with Personalized CRISPR Gene Therapy for Rare Disease is Now ‘Thriving’

Dr. Kiran Musunru (left) and Dr. Rebecca Ahrens-Nicklas (right) led the researchers who developed a personalized treatment for baby KJ – Released CHOP and Penn

CRISPR has been used to create a genetic therapy option for a child born in Pennsylvania with a rare metabolic disorder.

Unable to convert ammonia to urea, newborn KJ was in serious risk of brain or liver damage, and had to be kept on medications and an extremely restrictive diet to avoid protein metabolism.

Children’s Hospital of Philadelphia (CHOP) doctors believed they could use CRISPR to develop a treatment to correct a faulty gene in KJ’s genome that would essentially cure him.

KJ’s parents, Nicole and Kyle Muldoon, decided to place their son’s wellbeing in the hands of two pioneering genetic therapists, Dr. Rebecca Ahrens-Nicklas and Dr. Kiran Musunru, who crafted a bespoke treatment that has successfully corrected the genetic defect.

“Years and years of progress in gene editing and collaboration between researchers and clinicians made this moment possible, and while KJ is just one patient, we hope he is the first of many to benefit from a methodology that can be scaled to fit an individual patient’s needs,” said Rebecca Ahrens-Nicklas, MD, PhD, director of the Gene Therapy for Inherited Metabolic Disorders Frontier Program (GTIMD) at Children’s Hospital of Philadelphia.

She, along with Dr. Musunru, are members of the NIH-funded Somatic Cell Genome Editing Consortium, and have spent years developing the science of using CRISPR to create individual treatment doses for the rarest of diseases.

So far, the only FDA-approved and standardized CRISPR therapies target two diseases found in tens of thousands of patients. CRISPR is an incredibly complex tool and expensive to wield, leaving its magic beyond the reach of millions of children and adults worldwide who collectively suffer from extremely rare genetic disorders.

One such disorder is called severe carbamoyl phosphate synthetase 1 (CPS1) deficiency, and it creates the inability to properly convert ammonia into urea to be excreted through urine. Ammonia is created in the body through protein metabolism. CPS1 is created in the liver to turn it into urea so as to avoid the toxic effects of the former.

KJ’s body cannot, so excess protein metabolism creates a buildup of ammonia in his liver that could be fatal. Nitrogen scavenging medication and a protein-deficient diet can keep a patient going until a liver transplant can be found, but at just months old, KJ’s body isn’t capable of enduring the procedure.

A news release from CHOP reports that Ahrens-Nicklas and Musunuru targeted KJ’s specific variant of CPS1 after years of work with similar disease-causing variants. Within 6 months, their team designed and manufactured a base editing therapy delivered via lipid nanoparticles to the liver in order to correct KJ’s faulty enzyme.

In late February, 2025, KJ received his first infusion of this experimental therapy, and since then has received follow-up doses in March and April 2025, the release details. In the newly published New England Journal of Medicine paper, the researchers, along with their academic and industry collaborators, describe the customized CRISPR gene editing therapy that was rigorously yet speedily developed for administration to KJ.

KJ has received 3 doses, and suffered no side effects. He’s been able to halt medication and work some protein back into his diet, though he will need careful monitoring the rest of his life.“We thought it was our responsibility to help our child, so when the doctors came to us with their idea, we put our trust in them in the hopes that it could help not just KJ but other families in our position,” his mother, Nicole, told CHOP. Successful World First: Baby Treated with Personalized CRISPR Gene Therapy for Rare Disease is Now ‘Thriving’

Read More........→February 06, 2026