Fun Facts About the Nervous System That Actually Matter

Your Brain Isn’t What You Think It Is

So here’s something wild – your brain uses about 20% of your body’s total energy despite only being like 2% of your body weight. That’s according to research from the National Institutes of Health back in 2002, and honestly when you think about how much your phone battery drains when you’re using GPS versus just checking texts, it kind of makes sense.

The nervous system market was valued at $8.3 billion in 2023 according to Grand View Research, and companies like Medtronic and Abbott are dumping resources into neural interface technology. Which brings me to something most people don’t realize.

Your neurons can fire signals at speeds up to 268 miles per hour. That’s faster than a Formula 1 race car (tops out around 235 mph during actual races). But here’s the thing – not all neurons are created equal, and some of your pain signals actually travel pretty slowly, which is why sometimes you don’t feel pain immediately after an injury.

The Gut-Brain Thing Is Real (And Pharmaceutical Companies Know It)

AbbVie invested $63 billion to acquire Allergan in 2020, partly because of their neurogastroenterology portfolio. Your gut has something like 500 million neurons – that’s more than your spinal cord. People call it the “second brain” which sounds like marketing nonsense until you realize that 90% of your body’s serotonin is produced in your gut, not your brain.

Pfizer’s research division published data in 2019 showing that vagus nerve stimulation could reduce inflammation in rheumatoid arthritis patients. The vagus nerve is basically this massive highway connecting your brain to your gut, heart, and other organs. It’s the longest cranial nerve and honestly does way more than most medical textbooks gave it credit for until recently.

Want the latest on neural health? Get our monthly BrainWire newsletter with research updates and health tips from leading neurologists. Subscribe now

Memory Doesn’t Work Like Computer Storage

This drives me crazy when people compare brains to computers. MIT researchers found in 2017 that every time you remember something, you’re actually slightly changing that memory. It’s not like pulling up a saved file – it’s more like rewriting it each time. Which explains why eyewitness testimony is so unreliable and why your memories of childhood events probably conflict with your siblings’ memories.

The global cognitive assessment market hit $7.9 billion in 2022, with companies like Cambridge Cognition and Cogstate developing tests that pharmaceutical companies use in drug trials. These tests have gotten really good at detecting tiny changes in memory and processing speed.

Your brain has roughly 86 billion neurons (not 100 billion like everyone used to say – that got corrected by Brazilian neuroscientist Suzana Herculano-Houzel in 2009). Each neuron can form up to 10,000 connections with other neurons. Do the math on that and it’s kind of insane.

Sleep Actually Cleans Your Brain

Literally. The glymphatic system – discovered by University of Rochester researchers in 2012 – basically power-washes your brain while you sleep. The space between brain cells increases by 60% during sleep, allowing cerebrospinal fluid to flush out toxic proteins including the ones associated with Alzheimer’s.

Eisai and Biogen got FDA approval for Leqembi in January 2023, an Alzheimer’s drug that costs $26,500 per year and has to be administered intravenously every two weeks. The approval was controversial because the clinical benefit was pretty modest, but it showed that you could actually target amyloid buildup in the brain. Point being – we’re finally understanding that brain health isn’t just about neurons firing, it’s about the maintenance systems too.

People who consistently sleep less than 6 hours have a 30% higher risk of dementia according to a 2021 study published in Nature Communications. That study followed 8,000 people for 25 years. Twenty-five years! That’s a serious commitment to research.

Your Nervous System Regenerates (Sort Of)

Okay so everyone learned in school that you can’t grow new brain cells, right? Wrong. Adult neurogenesis is a thing, mainly in the hippocampus. A 2018 study in Cell Stem Cell found that healthy people continue producing new neurons well into their 90s, though the rate does decline.

The peripheral nervous system – nerves outside your brain and spinal cord – can actually regenerate pretty well. That’s why people can recover from nerve damage in their arms or legs. The central nervous system, not so much. That’s why spinal cord injuries are so devastating and why Neuralink (valued at around $5 billion as of their 2023 funding round) and other companies are trying to develop brain-computer interfaces.

Johns Hopkins reported in 2020 that they’d successfully transplanted nerve cells into patients with Parkinson’s disease. The cells survived and integrated, which was honestly unexpected. Clinical trials are ongoing but the results so far have been… mixed. Some patients showed improvement, others didn’t.

Pain Is Complicated and Weird

Phantom limb pain affects 60-80% of amputees according to the Cleveland Clinic. Your brain maintains a “map” of your body even after parts are removed, which is both fascinating and terrible. What’s interesting is that mirror box therapy – invented by neuroscientist V.S. Ramachandran in the 1990s – can actually help reduce phantom pain by tricking the brain with visual feedback.

Purdue Pharma infamously pushed OxyContin by downplaying addiction risks, leading to the opioid crisis that’s killed over 500,000 Americans since 1999. The company filed for bankruptcy in 2019 owing $8.3 billion. All because they exploited how pain signals work in the nervous system and how opioid receptors can hijack the brain’s reward pathways.

There are people with a genetic mutation (SCN9A gene) who literally cannot feel pain. Sounds great until you realize they don’t know when they’re injured or sick. One case study from 2006 documented a Pakistani street performer who would walk on hot coals and stab himself – he died at 14 from injuries sustained jumping off a roof.

The Autonomic Nervous System Runs On Autopilot

You’re not consciously controlling your heart rate, digestion, or pupil dilation right now. The autonomic nervous system handles all that, split between sympathetic (fight-or-flight) and parasympathetic (rest-and-digest) branches.

Nuance makes a product called Dragon Medical that uses speech recognition to help doctors dictate medical notes. The technology relies on understanding neural patterns of speech production, which involves Broca’s area in the left frontal lobe coordinating with motor cortex regions. What’s wild is that stroke patients who lose the ability to speak can sometimes still sing, because music processing happens in different brain areas.

Join the Neural Health Network Connect with 45,000+ healthcare professionals and researchers discussing the latest in neuroscience applications. Join today

Neuroplasticity Doesn’t Have an Age Limit

The idea that brains stop developing after childhood is outdated. London taxi drivers famously have enlarged hippocampi from memorizing 25,000 streets – a 2000 study by Eleanor Maguire at University College London proved this. And they don’t start training until adulthood.

Lumosity got fined $2 million by the FTC in 2016 for claiming their brain training games could prevent Alzheimer’s and dementia. The research just doesn’t back up those claims. But genuine cognitive training – like learning a new language or musical instrument – does create measurable changes in brain structure. The difference is the FTC doesn’t mess around with false advertising.

Stroke rehabilitation can work years after the initial injury because the brain can reroute functions around damaged areas. The NIH reported in 2018 that stroke patients who participated in intensive therapy even 2-3 years post-stroke showed significant recovery. Insurance companies typically only cover therapy for 3-6 months though, which is a whole separate problem.

Your Nervous System Has Some Genuinely Bizarre Features

Synesthesia affects about 4% of people – they might taste words or see numbers as colors. It’s caused by extra neural connections between normally separate brain regions. There’s no treatment because it’s not a disorder, it’s just a different wiring pattern. Some famous artists and musicians have it.

You can’t tickle yourself because your cerebellum predicts the sensation and cancels it out. Researchers at University College London proved this in 2000 using fMRI scans. But if there’s a delay between your action and the sensation – like using a robot arm – you CAN tickle yourself.

The brain has no pain receptors. Brain surgeons can operate on conscious patients (needed for mapping brain functions during tumor removal). The patient feels nothing from the brain tissue itself, though obviously the skull incision needs anesthesia. This is how they do awake craniotomies at places like Mayo Clinic and UCSF Medical Center.

So yeah. Your nervous system is running a lot of processes you’re not aware of, it’s more adaptable than textbooks suggested, and we’re still figuring out how it all works. The research coming out of labs like those at Stanford’s Wu Tsai Neurosciences Institute and the Allen Institute for Brain Science is genuinely exciting stuff, even if it takes decades to translate into treatments.