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  • Part 4: Dopamine: The Molecule of Addiction

  • Here's the normal pattern of dopamine release.

  • It looks something like a roller coaster

  • because in biology,

  • what goes up must come down.

  • It could be food,

  • sex or even water when you're thirsty.

  • So,

  • let's say you're hungry.

  • Dopamine starts rising.

  • Then you think about a burger

  • and it rises more.

  • When the burger is sizzling,

  • dopamine's going way up.

  • It peaks right about at your first bite

  • then you take some more bites

  • then it starts to drop off,

  • and finally drops back down to normal levels

  • and you're full.

  • This graph could also represent

  • masturbating or having sex

  • and the peak would be right about at orgasm.

  • However,

  • I really want to point out

  • that the experience of orgasm

  • is probably driven by other neurochemicals

  • called Opiate,

  • not dopamine.

  • So,

  • dopamine drives you toward orgasm

  • but

  • the feeling of orgasm arises from something else.

  • The rise of dopamine levels

  • could also represent anything new or novel,

  • because dopamine loves novelty.

  • A new car,

  • a just released movie,

  • the latest gadget,

  • we're all hooked on dopamine.

  • You can have a spike of dopamine

  • just by ordering dessert

  • even though you haven't finished what's on your plate.

  • Dessert is something new.

  • In fact,

  • dopamine surging in your reward circuitry

  • can override your feelings

  • of what's called satiety or fullness

  • regardless of what your rational brain may think

  • about overeating

  • or even watching porn.

  • As with everything new,

  • the thrill fades and dopamine levels drop.

  • Now,

  • back to the Coolidge Effect.

  • So,

  • dopamine is what is behind the Coolidge effect.

  • If you look at our little graphs here,

  • we have a female rat #1,

  • female rat #2 and

  • dopamine level.

  • What's happening is

  • that the reward circuitry of the male

  • is squirting less and less dopamine

  • in each copulation with female #1.

  • And eventually,

  • the male can no longer copulate,

  • because there's not enough dopamine.

  • Dopamine is behind libido.

  • Then you dropped in female #2

  • and the male gets another squirt of dopamine

  • which surges his libido

  • and he goes back to work.

  • This is what's behind the Coolidge effect

  • and it's also why you click on to new videos

  • while you're watching porn:

  • to get another big squirt of dopamine

  • with something novel.

  • Ok.

  • Let's give another nickname for dopamine.

  • Let's call it the molecule of addiction.

  • It's because changes in your brain

  • that lead to addiction

  • caused by changes in dopamine level.

  • Cocaine,

  • alcohol,

  • nicotine,

  • they all feel different

  • but all of them flood the reward circuitry

  • with dopamine.

  • All addictive chemicals and activities

  • raise dopamine levels.

  • It's what makes them potentially addictive.

  • Of course,

  • you need continued use of the addictive substance

  • or activity

  • to cause physical changes that lead to addiction.

  • Here's an odd thing.

  • We've mentioned it before.

  • Dopamine is released

  • in response to expectations,

  • rather than actual levels of pleasure.

  • It's the drive to get it,

  • it's the craving,

  • but as I've mentioned,

  • the actual pleasure of eating or orgasm

  • is probably opioids.

  • Those are morphine-like chemicals

  • being released in the brain.

  • Dopamine is wanting it,

  • Opiates are liking it.

  • Addictions are basically chasing after dopamine.

  • So,

  • what happen is

  • addiction is wanting more but liking it less.

  • Speaking of wanting

  • and the power of the reward circuitry,

  • here's an experiment.

  • We have a rat

  • and you see there's a wire

  • and then this electrode

  • that's actually going to the reward circuitry

  • of the rat.

  • And the rat has its little paw on lever

  • and whenever he hits the lever

  • it sends just enough electricity

  • to the reward circuitry to stimulate it.

  • Now,

  • what will happen is

  • this rat would just keep hitting the lever

  • and hitting the lever thousands of times an hour

  • until it drops.

  • It won't stop to eat,

  • sleep,

  • have sex or even take care of the pups.

  • It will give up everything

  • just to press that lever.

  • As we know,

  • this behavior

  • is not unlike some serious drug addicts.

  • Here's another experiment.

  • They take the same rat

  • and then they have an electric grid

  • between the lever and the rat

  • so the rat has to feel painful shock

  • in its little paws

  • to go over to the lever and press it.

  • Well,

  • the rat will actually cross the bridge

  • and endure the shock

  • but if you take the rat

  • and put it in electric grid between them and food,

  • they will not cross the electric grid.

  • They will not undergo shock to eat food,

  • they would rather starve.

  • Here's more experiment

  • to show the power of dopamine

  • in your reward circuitry.

  • If you take rats and block their dopamine,

  • they have absolutely no motivation.

  • They're not even eat.

  • They won't walk over to the food dish

  • and they'll starve to death.

  • But they still like food.

  • If you drop food into their mouth,

  • they eat it and show little rat's smiles,

  • they just have no motivation to go get it.

  • They lie around.

  • They won't have sex either.

  • The male rat shows no signs of libido.

  • The key point is

  • you need the right level of dopamine

  • to function normally.

  • It does lots of important jobs.

  • Dopamine gives you that positive outlook,

  • good attitude,

  • keeps you motivated, keeps you happy.

  • Incidentally,

  • many psychological problems

  • involved dopamine imbalances,

  • including addictions.

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Part 4: Dopamine: The Molecule of Addiction

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Part 4: Dopamine: The Molecule of Addiction | Your Brain on Porn | Animated Series

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    joey joey に公開 2021 年 04 月 25 日
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