Neural Plasticity
By Mikey Taylor
Edited by Varshini Sundaresan
PROCEED WITH CAUTION ⚠️
After reading this article, your brain literally won’t be the same…
Your brain may even change forever.
And no, it’s not because I’m some kind of magician (although I’ve always wanted to be one). This isn’t sorcery.
It’s because of one thing:
Your brain, is plastic.
*gasp*
Like your brain, plastic can be easily shaped and molded. Your brain is changing shape as you’re reading right now, whether you like it or not.
Sounds crazy, I know. But it’s true, and the process even has a name: neural plasticity.
Neural plasticity is the crazy phenomenon in which synapses and neural pathways change throughout your life due to environmental conditions, or learning something new.
You weren’t born knowing how to ride a bicycle; there’s no “bicycle riding” gene. But what you did do was practice. Bicycling is hard at first, but once you get the hang of it, chances are you never forget it. It is literally hardwired in your brain.
Whenever you learn to do something new, a new set of neurons fire in concert. This strengthens the connections between those neurons. And, like your parents told you when learning to ride a bike, practice is key; the more often these neurons are fired, the stronger the connections between them are.
The two parts of the brain most important in neural plasticity are the hippocampus, your hub for long-term and spatial memory, and your cerebellum, your hub for coordination and muscle memory.
This is because they’re full of granule cell neurons which have the highest rate of neurogenesis, or production of neurons.
In contrast, the sets of neurons that are fired less frequently weaken, and may even eventually disappear.
The synapses are strengthened in a process called long-term potentiation, and others are weakened, or “pruned,” in long-term depression.
Oh crap, a complicated diagram… hate to break it to you but this = extremely simplified
Glutamate can be thought of as the neurotransmitter that gets the party started — it’s excitatory 🎉 When glutamate is released, it binds to NMDA and AMPA receptors. Other positive ions (or partygoers, if you will) are able to enter the postsynaptic neuron via the AMPA receptor, but can’t get in through the NMDA receptor (because magnesium is an inhibitory party pooper blocking the door). But, if enough positive ions enter through the AMPA receptor, the cell will depolarize, kicking the magnesium out of the party. This means that the calcium can finally enter through the NMDA receptor!
But the party has just begun; because the calcium ions are super stoked to be at the party, they want to invite more guests… So they add a bunch more AMPA receptors, meaning the cell is more responsive to glutamate, and more guests can come inside. The synapse is now strengthened, in the process of long-term potentiation (party = success).
But let’s take a step back… this only occurs when the neuron is continually fired. What if we’re not activating this part of our brain? What if no one’s going to the party?!?
Then long-term depression occurs… sad 😥 There’s less glutamate removed because you’re not activating that neuron, meaning AMPA receptors are taken away — what’s the point of having doors to a party that no one’s going to? The cell eventually becomes less responsive to glutamate and the synapse weakens… If this loss of activation continues, the synapse may eventually experience what all synapses in the world fear:
SYNAPTIC PRUNING
*gasp*
“Shampoo press, get you out of my hair” → Synaptic prune, get you out of my brain… (Lizzo, I am so sorry.)
This is also why it’s much easier to pick up new information when you’re younger. Synapses start forming in your brain before you’re even born. Synapses keep rapidly forming until your about 2 years old in a process called exuberant synaptogenesis, making it wayyy easier to hardwire new info into your brain.
It’s not until you’re around 4 years old when neural circuits that aren’t activated as much start to disappear because having these neurons is a waste of materials and energy.
In this way, our brain is super smart economically as they provide high local and global efficiency of parallel information processing for a pretty low connection cost.
This “economic intelligence” actually has a name: a small-world network.
Basically, in a small-world network, there is increased local clustering of connections and a short path length between any of the nodes (the dots).
But as you now know, our connectome, or map of our individual brain, is not constant. And there are sooo many ways we can take advantage of this, one being meditation, but more interestingly, psychedelics…
Psychedelics, like LSD and DMT, have been shown to actually promote neural plasticity, showing strong therapeutic benefits. Psychedelics are “psychoplastogens,” if you will.
As can be seen above, the results are literally insane. The frequency at which cell branches and neurites crossed over each other were greatly increased by the psychedelics, in comparison to VEH (no drug).
Other studies have shown that LSD in particular has the potential to DOUBLE the number of dendritic spines on neurons:
Patients who suffer from neuropsychiatric disorders like treatment resistant depression and PTSD actually tend to have impaired neurogenesis and neural plasticity, leading to the atrophy of several brain regions like the prefrontal cortex and hippocampus. Psychedelics therefore have huge potential for therapeutic treatment by increasing neural plasticity.
The emerging field of neurotech also has the potential to modulate neural plasticity, specifically deep brain stimulation (DBS).
DBS is both an invasive and noninvasive treatment for brain disorders like Parkinson’s, Alzheimer’s, epilepsy, and even neuropsychiatric disorders. Electrodes are either placed on or in the brain and excite (or inhibit) neurons with an electrical impulse. This can literally increase connectivity between certain parts of the brain… DBS over a long period of time has been shown to induce the gradual reorganization of neural circuits via enhanced synaptic plasticity and neurogenesis.
The area of the brain directly targeted by the stimulating electrode (red region) is inactivated due to the stimulation of the presynaptic neuron GABAergic terminals, resulting in the release of GABA, an inhibitory neurotransmitter (A). Additionally, a depolarization block causes decreased activity in the neuronal cell bodies (B). (In simpler term km s, the activity of the red region is being inhibited by the stimulating electrode.)
DBS also causes an artificial, tonic pattern of neuronal firing by direct stimulation of axons in the region of the electrode, which travels to and thus affects other neurons, particularly neuron D labeled above (C & D). This means that DBS influences structures of the brain at a distance from the immediate target.
The altered firing patterns as a result of DBS can be associated with increased neurotransmitter release, changes in metabolism, and increased synaptic plasticity due to long-term potentiation. This is why it is such a promising treatment for neurological disorders, as it can directly impact the structure and function of different brain regions (E to G).
It’s important to remember that there are so many things you can do yourself to change your connectome; we don’t need psychedelics or a device. Exercising and meditating have been scientifically proven to increase neural plasticity, and mindfulness is a key technique in neurorehabilitation 📈
After all, you are LEGIT your connectome — your brain is structurally hardwired with all of your memories and experiences. With advancements in technology, I may be able to know all of your memories and experiences, solely based on your connectome.
But the key takeaway is to be mindful of your thought processes. You have the power to change them, and to rewire your brain. It’s only a matter of realizing it 🔑