A curious show and tell is going down on Reddit right now. Over in the 13-million-strong subreddit r/interestingasfuck, people are sharing scans of their brains in which it appears part of their brains are missing. How can this be possible? It all comes down to plasticity.

For example, back in 2016, a woman known as “EG” volunteered her brain scans to scientists because it was missing the left temporal lobe. She’d known nothing about it until a scan in 1987 revealed the missing lobe, and had otherwise lived a normal – and bilingual – life. We emphasize the fact she was bilingual because the temporal lobe is thought to be responsible for language processing in most people – and yet here was EG, speaking two languages.  

Functional magnetic resonance imaging (fMRI) showed that EG’s brain had found a way to compensate with a fully functional language network sitting in its right hemisphere. This kind of rewiring is an example of neural plasticity in which the brain changes through regrowth and reorganization.

Brain plasticity is what enables us to develop cognitively from infants into adulthood, constantly correcting small errors along the way. Things get trickier when severe errors occur due to strokes, diseases like Zika virus, or traumatic injury – but even in extreme examples, we’ve seen people recover a remarkable amount of function.

How EG’s brain adapted so well could have something to do with the timeline of her condition’s emergence.

“We find that—as expected for early left-hemisphere damage—EG has a fully functional language network in her right hemisphere [...] and intact linguistic abilities,” wrote the study authors. “However, we detect no response to language in EG's left frontal lobe.”

It’s thought a stroke when EG was very young may explain why this section of her brain is missing. The gap left behind is now filled with cerebrospinal fluid, which shows up on MRI as a dark space.

Similar dark empty spaces can be seen in a post by user brooklynlikestories. “Cool fact about my brain Basically when I was in the womb I had a stroke which caused a piece of my brain to be missing and just be a liquid sack if I’m saying that correctly,” they wrote in the comments. “So basically I wasn’t suppose to be able to walk talk run jump or anything like that usually people with this are in wheelchairs with breathing tubes the doctors consider me a miracle because they don’t know how or why my brain rewired itself.”

Other Reddit users have joined the conversation, sharing their experiences and scans – including an example of how arachnoid cysts can take up space in the brain. 

It’s nice to know that Tim Berners-Lee’s vision that The Web would connect people extends to people with remarkable brains, and we can all learn a bit about brain plasticity in the process.