Excito-toxicity: The Fatal Flaw of Mental Viagra

There’s one great myth regarding neuroscience that has been widely disseminated over the years: we only utilize about 10% of our brainpower. This may be true for those propagating this misinformation, like the team behind the new Hollywood film Limitless, but a flood of recent research is proving the opposite to be true.

Limitless finds its premise in the fallacy of the 10%. The hero of the movie, a writer suffering from a relentless bout of creative constipation, pops a made up pill called NZT that allows him to maximize his brainpower, from thinking more rapidly, to retaining every detail from his life and everyone else’s he crosses paths with. You can just imagine the dramatic hijinks that ensue based on his newly expanded neural bandwidth.

Harvard grad students started the wonderful trend of snorting Adderall in the early Aughts. They claimed it allowed them to work longer and be even more pathological than they already were. Think Tim Ferris on fast forward. But it wasn’t from some mystical activation of the 90 percent that was previously dormant.

The drug essentially allows more glutamate to bind to an NMDA receptor, opening the ion channel in the neuronal membrane so the nerve can bath in calcium (the stimulant). But the more frequently that happens, the more susceptible the receptor becomes to other free radicals that have serious negative effects.  Keep doing the drug and it will drown the dendrite faster than Jim Morrison in a Parisian bathtub.

So what about the 90 percent?

Several years ago, glial cells made a splash in the scientific community when it was discovered that they did far more than simply support the more active neuronal cells. The word glial is derived from the Greek γλία or glue, and for decades, it was assumed that glial cells played the gofer role of fetching proteins and oxygen for the more relevant neurons. You can’t keep a neuron alive in a Petri dish without the support of glia. They make up 90 percent of our gray matter, whereas neurons only comprise 10%, hence the origin of the myth.

Now it’s been proven that glial cells play a much more integral role than previously hypothesized. Not only do they aid in the cognitive processes directly (they respond to and release neurotransmitters), they are now thought to be the root of cognition itself.  The fast emerging star of the glial cell family is the astrocyte, which resides in the cortex, the area of the brain attributed to higher thought.

The discovery that astrocytes communicate with each other, as well as with neurons, overturned the long held Neuron Doctrine, which claimed that the dendrite and the synapse were the flirtatious starlets making all the cognitive magic.  It’s true that neurons are linked to muscular action and the processing of all five external senses, but we now know that astrocytes are monitoring these neurons and processing all the information.

Neurons tackle things like problem solving, and fight or flight, but what about all the thoughts occurring during the period scientists call “wakeful rest”? The seemingly spontaneous thoughts that pop up when we’re daydreaming, or jogging, or listening to a live band are coming from what researchers call the “default mode network”.  It’s another name for the domain of the brain dominated by glial cells.

The question remains, can we increase the effectiveness of either neurons or glial cells through chemistry?  What would be the real results if this network were maxed out on mental Redbull?  Would everyone become like the character in Limitless, a new Steven Hawking or Mozart or Leonardo da Vinci?

Signs point to no. As a matter of fact, odds are the opposite would happen. The onslaught would manifest itself in malfunctions much closer to autism and schizophrenia. We’re already seeing the negative effects of today’s non-stop stimulation blitzkrieg significantly shortening our attention spans. ADD and ADHD will reach epidemic levels soon enough.  Our brains are being over stimulated on so many levels that it begs the question; can a neuron be excited to death?  The answer according to scientists not working on hyperbolic Hollywood screenplays is hell yes.

So before you pop that little blue neurotransmitter enhancer, know that you aren’t unlocking access to innumerable and untapped doors of perception, nor are you going to end up in Vegas with Robert Deniro. You’re more likely stepping on the gas while the car is still in the proverbial garage.  If you want to increase your productivity, think about meditation, or my personal favorite, a mid-afternoon, post cabernet siesta.



  1. So many movies and tv shows out now covering this. Limitless was good for about an hour. Then the shoot’em up got boring. Intelligence is decent, but lots of holes in the story telling. Transcendance was interesting but again went off the rails. Lot of Singularity memes out there. Can we make a replica of our brains that function better than the real thing? It’s probably just a matter of time.

  2. I’m happy using ten percent of my brain. I find myself pretty on the ball and fairly capable of remembering the relevant things. Any more brain power, and I just might start to see things as they really, which is you know what…. Ignorance is bliss. More please.

  3. Lots of food for thought here. Get it 😉

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