https://www.youtube.com/watch?v=H-XfCl-HpRM&list=PLPNW_gerXa4Pc8S2qoUQc5e8Ir97RLuVW&index=103&ab_channel=AndrewHuberman
What is the Nervous System?
- The nervous system consists of the brain, the spinal cords, all the connections from the brain and the spinal cord to the organs, and all the connections back from the organs to the brain and the spinal cord.
- Our nervous system is a continuous loop of communication between the brain, spinal cord, and body as well as the body, spinal cord, and brain. One can’t really distinguish between the two as they are closely intertwined.
What is it made of?
- It was believed that the nervous system was one giant cell but later on, it was discovered that we are made up of trillions of small nerve cells called
neurons
.
- These nerve cells don’t touch each other. They are separated by small gaps called
synapses
. Synapses are where the chemicals from one nerve cell are spitted out into. The next nerve cell detects those chemicals and sends electricity down its body to the next nerve cell, and so on.
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⚾ Thus, the way to think about our mind and our body is that we are nothing but a flow of electricity between these neurons, and depending on which neurons are active, we might be doing/perceiving/thinking/feeling different things. Our experience of the world makes us think that the things that are outside of us are happening inside us (for example, when we perceive an object as red or green) even though the language of the nervous system is just electricity.
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How does the nervous system work then?
- Our experiences and memories are analogous to pressing the keys on a piano in a certain order, with a certain intensity leading to a certain song.
- A particular key, like E#, is not the song. It is just a component of the song. E.g. A part of the brain called the hippocampus is involved in memory but memory is not really stored in the form of sentences. It is stored as patterns of electricity in neurons, that, when repeated, give you the sense that you’re experiencing it again.
- This is what underlies Deja Vu where the neurons that were active in one circumstance are becoming active in the same circumstance again. This is why even if you play the same song on a different instrument, there is something similar about the two types of sounds even though they are played on different instruments.
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🏷️ The two main takeaways so far:
- There is much more to our nervous system than the brain (like neurons and synapses)
- It is the electrical activity of these neurons that dictate our experiences.
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How has warfare helped us figure out how different parts work?
- A new set of bullets were designed which would enter one part of the brain and leave the other part by creating discrete holes (as opposed to large ones as before). Thus, only discrete parts of the nervous system would get destroyed by such bullets. Even cleaning wounds became much better due to which a lot more people were surviving.
- The people who came back from warfare would have holes in their brains and other parts of the nervous system that were limited to very specific locations. They might say (for example) that are able to recognize faces but not able to remember who those faces belong to. Upon their death, neuroscientists would observe which part of the brain was damaged in their case and this is how, for example, they were able to figure out how particular regions of the brain like the hippocampus work.
- Others would come and speak jibberish (who used to be able to speak properly) while understanding the language perfectly.
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⛄ Through the example above, we were able to discover that speech and language are controlled by separate portions of the nervous system.
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