Below is my notes for the Huberman Lab Podcast. In the first episode, Dr. Huberman discuses how your nervous system works and changes. Enjoy!
What is the Nervous System
The nerve system includes your brain and your spinal cord, but also all the connections between your brain, your spinal cord, and the organs of your body. It also includes, very importantly, all the connections between your organs back to your spinal cord and brain. Your nervous system is a continuous loop of communication between the brain, spinal cord, and the body; and body, spinal cord, and brain. Like a Mobius strip.
The nervous system governs all other biological systems of the body, and it's also influenced by those other biological systems.
Synapses are where the chemicals from one neuron are kind of spit out or vomited into. And then the nest nerve cell detects those chemicals and then passes electricity down its length to the next nerve cell and so forth.
The way to think about your body, your thoughts, and your minds is that you are a flow of electricity between these different nerve cells.
Hippocampus is the brain area which involved in memory. Memories stored there as patterns of electricity in neurons that when repeated, give you the sense of that you're experiencing the thing again. In fact, deja vu, the sense that what you're experiencing is so familiar and like something that you've experienced previously is merely that the neurons that were active in one circumstance are now becoming active in the same circumstance again.
Jennifer Aniston Neurons
If you know the famous actress Jennifer Aniston, then you have a Jennifer Aniston Neurons, which is a theory on memory proposed by Mr.Quiroga.
Sensation is a non-negotiable element of your nervous system. For example, You have neurons in your eye that perceive certain colors of light and certain directions of movement.
Perceptions & The Spotlight of Attention
Perception is our ability to take what we're sensing and focus on it and make sense of it, to explore it, to remember it. So perceptions are just whichever sensations we happen to be paying attention to at any moment. Perception is under the control of your attention.
Multi-Tasking Is Real
The way to think about attention is it's like a spotlight, except it's not one spotlight. You actually have two attentional spotlights.
Primates are Abel to do what's called covert attention. We can place a spotlight of attention on reading or listening. And, we can place a second spotlight of attention on something we're eating and how it tastes or our child/dog running around in the room. You can split your attention into two locations. Of course, you can also bring your attention, that is your perception to one particular location. You can dilate your attention, kind of like making a spotlight more diffuse, or you can make it more concentrated.
Focusing the Mind
The moment you try to do something very specific, you're going to feel a sort of mental friction, which make the task challenging.
Emotions + The Chemicals of Emotions
Certainly, emotions and feelings are the products of the nervous system, because they involve the activity of neurons, which are electrically active and release chemicals. Neuromodulators(like dopamine,serotonin, acetylcholine, and epinephrine) are substances that have a very profound influence on our emotional states. They are like playlists that you would have on any kind of device where you're going to play particular categories of music.
For example, serotonin is a molecule when released tends to make us feel really good with what we have, our sort of internal landscape and the resources that we have. Whereas, dopamine, more than being a molecule of reward, is really more a molecule of motivation toward things that are outside us and what we want to pursue.
Most of the autidepressants, especially in the 1950s and 60's, would reduce serotonin, but they would also reduce dopamine; or they would increase serotonin but they would also increase some other neuromodulators chemical. That is because al these chemical systems in the body, but the neuromodulators in particular, have a lot of receptors, which cause neuromodulators have different effects on different aspects of our biology.
Thoughts & Thought Control
In many ways, thoughts are like perceptions. Excepts they draw on not just what's happening in the present, but also things we remember from the past, and things that we anticipate about the future.
Thoughts can be reflective and deliberate.
The sensations, perceptions, the thoughts, and the feeling of that we have in our lifespan, none of that is actually carried forward except the ones that we take and convert into actions such as writing, words, engineering new things. So, the fossil record of our species and each one of us is really through action. And that, in part, is why so much of our nervous system is devoted to converting sensation, perceptions, feelings, and thoughts into actions.
The aspect of our nervous system of creating movement occurs through some very simple pathways, the reflexive pathway. It basically includes areas of the brain stem we call central pattern generators.
Movements, just like thoughts, can be either reflexive or deliberate. When you do something deliberately, you pay attention and you are bringing your perception to an analysis of three things.
- duration - how long something is going to take or should be done
- path- what you should be doing
- outcome - if you do something for a given length of time, what's going to happen Anytime you're deliberately forcing yourself over a threshold, you're engaging the DPO brain circuits that suddenly make it feel as if something is challenging.
How We Control Our Impulses
Impulsivity is a lack of top-down control, a lack of top-down processing. The other thing that will turn off the forebrain and make it harder to top-down processing is a couple of drinks containing alcohol. The removal of inhibition is actually removal of neural inhibition of nerve cells suppressing the activity of other nerve cells.
Neuroplasticity: The Holy Grail of Neuroscience
Plasticity itself is just a process by which neurons can change their connections and the way they work. So that you can go from things being very challenging and deliberate, requiring a lot of effort and strain to them being reflexive.
If you're an adult and you want to change your neural circuitry at the level of emotions, behavior, thoughts, or anything really, you absolutely need to ask two important questions.
- What particular aspect of my nervous system am I trying to change? Meaning, are you trying to change your emotions, perceptions, or sensations? And which ones are available for you to change?
- How are you going to do about that? What is the structure or the regimen to engage neuroplasicity? And it turns out the answer to the this question is governed by how awake or how sleepy we are.
Neuroplasticity is the ability for these connections in the brain and the body to change in response to experience. What's so incredible about the human nervous system in particular is that we can direct our own neural changes. We can decide that we want to change our brain. In other words, our brain can change itself. And the same can't be said for other organs of the body.
The Portal to Neuroplasticity
Plasticity in the adult human nervous system is gated, meaning it is controlled by neuromodulators. Dopamine, serotonin, and acetylcholine are what open up plasticity. They literally unveil plasticity and allow brief periods of time, in which whatever information, whatever thing we're sensing, perceiving, thinking or feeling can literally be mapped in the brain such that later it will become much easier for us to experience and feel that thing.
Epinephrine creates the alertness, and acetylcholine coming from an area of forebrain is tagging or making the neurons that are particularly active during this heightened level of alertness. That makes the cells, the neurons and the synapses for strengthening, for becoming more likely to be active in the future.
The Pillar of Plasticity
What governs the tradition between alert and focused and these deep rest/states is a system in our brain and body, a certain aspect of the nervous system called the autonomic nervous system.
Leveraging Ultradian Cycles & Self Experimentation
Circadian system is 24-hour rhythms. Ultradian rhythms occur throughout the day and they require less time, they are shorter. 90-minute rhythm is the most important ultradian rhythm for this discussion. Our sleep is broken up into 90-minute segments.We, as human, are optimized for focus and attention with these 90-minute cycles. For the 5 or 10 minutes of those cycles, it's well-known that the brain and the neural circuits and the neuromodulators are not going to be optimally tuned to whatever it is you're trying to do. But as you drop deeper into that 90-minute cycle, your ability to focus and to engage in this DPO process and to direct neuroplasticity and to learn is actually much greater. And then you eventually pop out of that cycle.