10 ms·

Coffee drinkers display a distinct pattern of brain functional connectivity

83 points by pizza 6y ago

the_optimist 6y ago
"It is important to note, however, that causality cannot be inferred from our study design."
- HDMI_Cable 6y ago
  Observational studies are still useful, even if they can’t prove causation. A study like this can open new question into how coffee effects the brain.
  - tpoacher 6y ago
    or why some people's brains like coffee
barnabees 6y ago
"Fifty-six subjects were recruited (32 CD and 24 NCD). One participant from the CD group was excluded due to imaging artifacts, rendering a final sample of 31 CD and 24 NCD." Feels too small of a sample size to make any strong conclusions
- xyzzyz 6y ago
  Not necessarily. Suppose, for simplicity, that we have equal number N of coffee drinkers and non coffee drinkers, for total of 2N. Suppose you try your model on them, and tell which is which based on their MRI 80% of the time. Let’s assume the null hypothesis is that you model doesn’t work, and you just were randomly lucky. If N = 5, that’s 8 successes in 10 Bernoulli trials, that’s already p value of 0.01. With N=25 (close to the study), that’s p-value of 0.002, much better than random chance. Whether N = 50 is too small sample really depends on the strength of the effect you are trying to detect. For strong effects it’s plenty enough.
  - graderjs 6y ago
    Thank you for this. It's annoying to see people dismiss studies based some general idea of "not enough people" without being backed by the numbers. Great to see someone back it up!
  - throwawaytemp27 6y ago
    Your math is whack. 8/10 coin flips being a 1% chance?
    - deleted 6y ago
      [deleted]
    - muraiki 6y ago
      The commenter isn't saying that there's a 1% chance of getting 8/10 coin flips. One way that we can test whether a procedure is better than random chance is to use a binomial test. This helps understand whether a proposed rate of success is feasible or not, assuming that every attempt has equal probability. Here, success would be that the procedure distinguishes between coffee and non-coffee drinkers using an MRI. To evaluate "better than random chance" (vs "different than random chance"), we can use the binomial test to understand the probability that the rate of success is greater than 50%. In R, we can do this with: binom.test(8, 10, p=0.50, alternative="greater") which returns a p-value of 0.05469 and a 95% confidence interval of 0.4930987, 1 [see note below]. This doesn't meet the traditional threshold of 95% confidence, which (in a simplified way) says that we're ok with a 5% chance of a false positive if we repeated this testing procedure many times. So yes, this isn't a p-value of 1%. If we expand this to 20/25 successes, we have a lot more evidence. The p-value shrinks to 0.002039 and a 95% CI becomes 0.6245949, 1 [see note below]. So we're almost certain that the procedure has a success rate greater than 0.5, but without going deeply into the confusing aspects of how to correctly interpret confidence intervals and instead interpreting them as they are generally used, anywhere from 62% to 100% is reasonable if we're ok with a 5% false positive rate, which is still a wide range (the width is what I'd say is important, ignoring the way people use CIs in practice). Another way to do this would be to get a p-value as to how feasible a less-than 80% success rate is for 20/25 successes. That has a p-value of 0.5793, which isn't significant at any commonly used level. In the end, you'd probably use something more sophisticated than a binomial test so that you can account / control for other factors, but hopefully this illustrates what you can do with small sample sizes. Math details: https://en.wikipedia.org/wiki/Binomial_test#Usage https://en.wikipedia.org/wiki/Binomial_test#Usage Note: The upper range is always 1 because of details around calculating a one-sided binomial confidence interval (we're doing "greater than" rather than "different than").
excitednumber 6y ago
Can someone translate this to lay terms?
- TaupeRanger 6y ago
  There's something similar in the brain activity of people that drink coffee. That's it really.
- LesserEvil665 6y ago
  Coffee turns you into Tweek from South Park.
- SllX 6y ago
  Well, I’m not really qualified, but reading the abstract, they took a bunch of pictures of the brains of a small group of people, did some stats analysis where it is all linked, and the pictures seem to suggest that the CD group might feel less, be worse at processing whatever it is they do feel and suck more at moving parts of their body compared to the NCD group because all the feely parts and some of the movey-limb parts have fewer functional connections. Anxiety might be higher, especially if they’re male. I’ve been drinking coffee since I was 4 years old, so that would suck and maybe explain why I can’t do sports so good. Not all bad news, the CD group might have more functional connections between the seeing parts of the brain and the movey parts. Just going to quote this last part, seems like plain enough English: “In conclusion, higher consumption of coffee and caffeinated products has an impact in brain functional connectivity at rest with implications in emotionality, alertness, and readiness to action.” So, if you drink a lot of coffee, for like a long time, your fight or flight instincts are probably cranked too high. I think they probably also want more grant money so that they can take more brain pictures which honestly seems like a cool gig.
  - inopinatus 6y ago
    I can definitely see the academic appeal: "This is your brain" "This is your brain on high altitude Yirgacheffe" "This is your brain after a Jamaican blue mountain medium roast long macchiato served with a croissant and the wifi password" "Sir, please stop flirting with the wait staff"
mensetmanusman 6y ago
Coffee is the best drink ever, but how do we get it to taste as good as it smells?
- mssundaram 6y ago
  I think that they're pretty directly related, though maybe that's because I associate the smell with the resultant feeling of being caffeinated. However, I do recall smelling coffee brewing that both did not smell good and then did not taste good either.
  - hutzlibu 6y ago
    "though maybe that's because I associate the smell with the resultant feeling of being caffeinated" Maybe not, as I am not a coffee drinker and don't like being caffeinated - but I really do like the smell of coffee, too.
- nohr 6y ago
  If you're genuinely curious, James Hoffman on YouTube is the coffee wizard. All his videos are interesting, even if you couldn't care less about coffee!
  - wcunning 6y ago
    Seconded, though beware the upgrade-itis from watching too much of it...
  - emptyfile 6y ago
    Dude made me switch to a V60 filter after 15 years of drinking turkish coffee. I have to say, its amazing, I'm not going back. My coffee expenses are up 300%. Looking at burr grinders.
- yunruse 6y ago
  I find it lovely to use as an ingredient for a cupcake-in-a-mug; the texture really complements the coffee flavour.
- 6y ago
WalterBright 6y ago
When the pandemic started a year ago, I laid in a supply of coffee. The supply chain for that is very long, and I'd miss it terribly! I expected coffee shortages at the supermarket, but weirdly everyone else was buying yeast and toilet paper. Couldn't buy yeast for like 6 months. The coffee supply was unaffected, for which I am grateful!
- porknubbins 6y ago
  Well covid wouldn’t be expected to increase coffee consumption so the supply was ok. As someone into baking before all this- the amount of 5lb flour sacks and tiny yeast packets for $1.50 is there only to satisfy only frivolous occasional bakers. How do I know? Because it you were serious about baking you would buy this yeast and flour for pennies on the dollar in bulk at somewhere like Costco.
  - tolbish 6y ago
    These frivolous bakers would love to become serious bakers. The shortage of baking ingredients caused by the shutdown just means that people really like to bake if they have the time and energy.
    - pengaru 6y ago
      > The shortage of baking ingredients caused by the shutdown just means that people really like to bake if they have the time and energy. Or that they comfort eat more baked foods when cooped up and depressed while the world grinds to a halt for a year.
      - tolbish 6y ago
        Flour and yeast flew off the shelves at the very beginning of the pandemic before depression could set in.
        pengaru 6y ago
S_A_P 6y ago
I don’t see this in any of the comments but looks like coffee is associated with higher levels of anxiety in males. I skimmed the part about Alzheimer’s and dementia but I think I parsed it as it may help prevent it?
digitalsushi 6y ago
There's two posts on HN tonight, lemme be incendiary: Right now a magical being appears before you and lets you know if you can give up one of beef or coffee, that the world will be saved. Do you pick one? Which?
- NoPicklez 6y ago
  Probably beef, I can just eat chicken which is arguably better for you.
- tpoacher 6y ago
  Double up and pick both for good measure, on the provision that the magical being and all its friends and family suffer for all eternity if it had gotten this wrong. Does the magical being still want to go through with the offer?
- bagacrap 6y ago
  there's nothing I wouldn't give up to save the world...
- kbenson 6y ago
  Tough choice. I drink coffee more often (almost every day) and enjoy it, but could replace it with other things I think. Beef is in a lot of my favorite foods. I think I would give up coffee. If the question is beef or caffeine, it's a harder choice.
Balgair 6y ago
Aside: I gave up caffeine during quarantine. My anxiety is down and my sleep is much better. I know this isn't for everyone. But if you're having issues with anxiety or sleep, my anecdata says that caffeine may be the culprit. The first three days of headaches were pretty bad though, so be warned.
- kup0 6y ago
  One way to avoid the headaches is to taper slowly off of caffeine over a few days instead of dropping it completely. Just lower the "dose" you intake each day
- YoungWeb 6y ago
  Yes I try not to drink coffee for more than 7 days in a row. If I do I know I have a "detox" day ahead of me. Which is basically me not drinking coffee on a Sunday and suffering through a big old headache, sleepiness and possibly a little bit of nausea and dizziness. The coffee ween off is real.
  - Balgair 6y ago
    I had heard it was a bad headache, so I also tried weening myself off it with ever smaller scoops of grounds. Still, when I finally quit, it was a much stronger headache than I was anticipating. It really was one of the worst headaches I've had, and it lasted ~two days. That said, my SO will never let me have caffeine again. My SO says that I am so much nicer to be around and that I sleep much better too. I don't anticipate going back on the java, my life is much better. But everyone is different!

83 points by pizza 6y ago

the_optimist 6y ago

"It is important to note, however, that causality cannot be inferred from our study design."

HDMI_Cable 6y ago
Observational studies are still useful, even if they can’t prove causation. A study like this can open new question into how coffee effects the brain.
- tpoacher 6y ago
  or why some people's brains like coffee

barnabees 6y ago

"Fifty-six subjects were recruited (32 CD and 24 NCD). One participant from the CD group was excluded due to imaging artifacts, rendering a final sample of 31 CD and 24 NCD." Feels too small of a sample size to make any strong conclusions

xyzzyz 6y ago
Not necessarily. Suppose, for simplicity, that we have equal number N of coffee drinkers and non coffee drinkers, for total of 2N. Suppose you try your model on them, and tell which is which based on their MRI 80% of the time. Let’s assume the null hypothesis is that you model doesn’t work, and you just were randomly lucky. If N = 5, that’s 8 successes in 10 Bernoulli trials, that’s already p value of 0.01. With N=25 (close to the study), that’s p-value of 0.002, much better than random chance. Whether N = 50 is too small sample really depends on the strength of the effect you are trying to detect. For strong effects it’s plenty enough.
- graderjs 6y ago
  Thank you for this. It's annoying to see people dismiss studies based some general idea of "not enough people" without being backed by the numbers. Great to see someone back it up!
- throwawaytemp27 6y ago
  Your math is whack. 8/10 coin flips being a 1% chance?
  - deleted 6y ago
    [deleted]
  - muraiki 6y ago
    The commenter isn't saying that there's a 1% chance of getting 8/10 coin flips. One way that we can test whether a procedure is better than random chance is to use a binomial test. This helps understand whether a proposed rate of success is feasible or not, assuming that every attempt has equal probability. Here, success would be that the procedure distinguishes between coffee and non-coffee drinkers using an MRI. To evaluate "better than random chance" (vs "different than random chance"), we can use the binomial test to understand the probability that the rate of success is greater than 50%. In R, we can do this with: binom.test(8, 10, p=0.50, alternative="greater") which returns a p-value of 0.05469 and a 95% confidence interval of 0.4930987, 1 [see note below]. This doesn't meet the traditional threshold of 95% confidence, which (in a simplified way) says that we're ok with a 5% chance of a false positive if we repeated this testing procedure many times. So yes, this isn't a p-value of 1%. If we expand this to 20/25 successes, we have a lot more evidence. The p-value shrinks to 0.002039 and a 95% CI becomes 0.6245949, 1 [see note below]. So we're almost certain that the procedure has a success rate greater than 0.5, but without going deeply into the confusing aspects of how to correctly interpret confidence intervals and instead interpreting them as they are generally used, anywhere from 62% to 100% is reasonable if we're ok with a 5% false positive rate, which is still a wide range (the width is what I'd say is important, ignoring the way people use CIs in practice). Another way to do this would be to get a p-value as to how feasible a less-than 80% success rate is for 20/25 successes. That has a p-value of 0.5793, which isn't significant at any commonly used level. In the end, you'd probably use something more sophisticated than a binomial test so that you can account / control for other factors, but hopefully this illustrates what you can do with small sample sizes. Math details: https://en.wikipedia.org/wiki/Binomial_test#Usage https://en.wikipedia.org/wiki/Binomial_test#Usage Note: The upper range is always 1 because of details around calculating a one-sided binomial confidence interval (we're doing "greater than" rather than "different than").

excitednumber 6y ago

Can someone translate this to lay terms?

TaupeRanger 6y ago
There's something similar in the brain activity of people that drink coffee. That's it really.
LesserEvil665 6y ago
Coffee turns you into Tweek from South Park.
SllX 6y ago
Well, I’m not really qualified, but reading the abstract, they took a bunch of pictures of the brains of a small group of people, did some stats analysis where it is all linked, and the pictures seem to suggest that the CD group might feel less, be worse at processing whatever it is they do feel and suck more at moving parts of their body compared to the NCD group because all the feely parts and some of the movey-limb parts have fewer functional connections. Anxiety might be higher, especially if they’re male. I’ve been drinking coffee since I was 4 years old, so that would suck and maybe explain why I can’t do sports so good. Not all bad news, the CD group might have more functional connections between the seeing parts of the brain and the movey parts. Just going to quote this last part, seems like plain enough English: “In conclusion, higher consumption of coffee and caffeinated products has an impact in brain functional connectivity at rest with implications in emotionality, alertness, and readiness to action.” So, if you drink a lot of coffee, for like a long time, your fight or flight instincts are probably cranked too high. I think they probably also want more grant money so that they can take more brain pictures which honestly seems like a cool gig.
- inopinatus 6y ago
  I can definitely see the academic appeal: "This is your brain" "This is your brain on high altitude Yirgacheffe" "This is your brain after a Jamaican blue mountain medium roast long macchiato served with a croissant and the wifi password" "Sir, please stop flirting with the wait staff"

mensetmanusman 6y ago

Coffee is the best drink ever, but how do we get it to taste as good as it smells?

mssundaram 6y ago
I think that they're pretty directly related, though maybe that's because I associate the smell with the resultant feeling of being caffeinated. However, I do recall smelling coffee brewing that both did not smell good and then did not taste good either.
- hutzlibu 6y ago
  "though maybe that's because I associate the smell with the resultant feeling of being caffeinated" Maybe not, as I am not a coffee drinker and don't like being caffeinated - but I really do like the smell of coffee, too.
nohr 6y ago
If you're genuinely curious, James Hoffman on YouTube is the coffee wizard. All his videos are interesting, even if you couldn't care less about coffee!
- wcunning 6y ago
  Seconded, though beware the upgrade-itis from watching too much of it...
- emptyfile 6y ago
  Dude made me switch to a V60 filter after 15 years of drinking turkish coffee. I have to say, its amazing, I'm not going back. My coffee expenses are up 300%. Looking at burr grinders.
yunruse 6y ago
I find it lovely to use as an ingredient for a cupcake-in-a-mug; the texture really complements the coffee flavour.
6y ago

WalterBright 6y ago

When the pandemic started a year ago, I laid in a supply of coffee. The supply chain for that is very long, and I'd miss it terribly! I expected coffee shortages at the supermarket, but weirdly everyone else was buying yeast and toilet paper. Couldn't buy yeast for like 6 months. The coffee supply was unaffected, for which I am grateful!

porknubbins 6y ago
Well covid wouldn’t be expected to increase coffee consumption so the supply was ok. As someone into baking before all this- the amount of 5lb flour sacks and tiny yeast packets for $1.50 is there only to satisfy only frivolous occasional bakers. How do I know? Because it you were serious about baking you would buy this yeast and flour for pennies on the dollar in bulk at somewhere like Costco.
- tolbish 6y ago
  These frivolous bakers would love to become serious bakers. The shortage of baking ingredients caused by the shutdown just means that people really like to bake if they have the time and energy.
  - pengaru 6y ago
    > The shortage of baking ingredients caused by the shutdown just means that people really like to bake if they have the time and energy. Or that they comfort eat more baked foods when cooped up and depressed while the world grinds to a halt for a year.
    - tolbish 6y ago
      Flour and yeast flew off the shelves at the very beginning of the pandemic before depression could set in.
      - pengaru 6y ago

S_A_P 6y ago

I don’t see this in any of the comments but looks like coffee is associated with higher levels of anxiety in males. I skimmed the part about Alzheimer’s and dementia but I think I parsed it as it may help prevent it?

digitalsushi 6y ago

There's two posts on HN tonight, lemme be incendiary: Right now a magical being appears before you and lets you know if you can give up one of beef or coffee, that the world will be saved. Do you pick one? Which?

NoPicklez 6y ago
Probably beef, I can just eat chicken which is arguably better for you.
tpoacher 6y ago
Double up and pick both for good measure, on the provision that the magical being and all its friends and family suffer for all eternity if it had gotten this wrong. Does the magical being still want to go through with the offer?
bagacrap 6y ago
there's nothing I wouldn't give up to save the world...
kbenson 6y ago
Tough choice. I drink coffee more often (almost every day) and enjoy it, but could replace it with other things I think. Beef is in a lot of my favorite foods. I think I would give up coffee. If the question is beef or caffeine, it's a harder choice.

Balgair 6y ago

Aside: I gave up caffeine during quarantine. My anxiety is down and my sleep is much better. I know this isn't for everyone. But if you're having issues with anxiety or sleep, my anecdata says that caffeine may be the culprit. The first three days of headaches were pretty bad though, so be warned.

kup0 6y ago
One way to avoid the headaches is to taper slowly off of caffeine over a few days instead of dropping it completely. Just lower the "dose" you intake each day
YoungWeb 6y ago
Yes I try not to drink coffee for more than 7 days in a row. If I do I know I have a "detox" day ahead of me. Which is basically me not drinking coffee on a Sunday and suffering through a big old headache, sleepiness and possibly a little bit of nausea and dizziness. The coffee ween off is real.
- Balgair 6y ago
  I had heard it was a bad headache, so I also tried weening myself off it with ever smaller scoops of grounds. Still, when I finally quit, it was a much stronger headache than I was anticipating. It really was one of the worst headaches I've had, and it lasted ~two days. That said, my SO will never let me have caffeine again. My SO says that I am so much nicer to be around and that I sleep much better too. I don't anticipate going back on the java, my life is much better. But everyone is different!