Imagine going to the doctor for a check-up and finding out you are missing a vital part of your brain. This is what happened in 1987 to a woman — referred to as EG— who had no prior knowledge of her condition before this scan.
In accounts from EG and those who know her, no unusual behavior was reported. She even managed to get an advanced degree and learn multiple languages. This is all the more surprising as it was EG’s temporal lobe that is missing, the part of the brain associated with processing language.
In 2016, EG approached MIT scientists via email, telling them “I have an interesting brain.” It was a journey to be open about her condition, and, for a long time, she only told her close circle of friends. “It creeped me out,” she admitted, explaining the long gap between diagnosis and the study.
MIT referred her to cognitive neuroscientist Evelina Fedorenko from Harvard, who lapped up the opportunity to study such a medical marvel. Fedorenko and her team have since been studying EGs brain to figure out how it adapted without such a key component, with their results finally being published in Neuropsychologia last month.
They did this by scanning the organ in an fMRI machine while EG simultaneously engaged in language and mathematical processing. This way, the team was able to see where electrical signals were firing, and therefore, which regions were being engaged.
Surprisingly, they found no activity at all on the left side of the brain when processing language, with the right taking on all the responsibility. The team hypothesized EG lost her temporal lobe in a stroke when she was young, and her right brain compensated to allow her to communicate normally.
A closer look into her family’s brains revealed EG’s sister also had no temporal lobe. This is an indication that there is a genetic component to the stroke and plasticity in the recovery process.
This research reiterates what we already know: the brain is a complex and adaptable organ. “If you can remove half of a brain and you work fine, that suggests there’s a lot of bits in our typical brains that are redundant,” says Fedorenko. “There’s apparently a lot of stuff in our brain that is fully redundant, which is—engineering-wise—a pretty good way to build the system.”
Learning more about the brain’s plasticity will help forward understanding to many areas of neurology, especially in understanding stroke recovery and language development. “We know very little about how the system develops,” explains Fedorenko. To currently investigate this requires scanning children’s brains between the ages of one and three whose language abilities are still developing. “And we just don’t have tools for probing kids’ brains at that time.”