5 ms·

Where are you seeing that? Also, fine density/volume/mass, does it really change the argument? There is some optimal size for this region when it comes to cert

by nonbel 9y ago

Where are you seeing that? Also, fine density/volume/mass, does it really change the argument? There is some optimal size for this region when it comes to certain functions, probably relative to the size of other regions. That size is probably suboptimal when it comes to other functions and there are tradeoffs going on. The press release seems to be assuming that thinner is bad automatically.

MikkoFinell 9y ago
Yeah I do believe it makes a difference, because brain atrophy is linked to a range of cognitive impairments, for example strongly correlated with Alzheimer's disease. But you're right on the last point though, about assuming thinner is bad automatically. Heavy and chronic cannabis usage has been linked to an increase in density, but a reduction in total volume, which resulted in a slight overall decrease in IQ. The takeaway from all this being: Cognitive function is affected by a variety of parameters and we got more neuroscience to do still.
- nonbel 9y ago
  >"Heavy and chronic cannabis usage has been linked to an increase in density, but a reduction in total volume, which resulted in a slight overall decrease in IQ." I wouldn't put much stock into these type of non-quantitative explanations wherein "this makes that go up which makes this go down", etc. Usually the researchers measure a bunch of different things, analyze the data in a bunch of different ways, and only publish whatever is "significant". This works at the single lab level and multi-lab level since the "non-significant" results are considered boring and don't get published. By "usually" I mean this is standard behavior. You can call it p-hacking, file drawer effect, and more recently "forking paths": http://andrewgelman.com/2017/12/29/forking-paths-plus-lack-theory-no-reason-believe/ http://andrewgelman.com/2017/12/29/forking-paths-plus-lack-t... >"Cognitive function is affected by a variety of parameters and we got more neuroscience to do still." Sure, that was the case before these studies were done too though.
always_good 9y ago
> The press release seems to be assuming that thinner is bad automatically. Well, it's not unreasonable. I don't know of any literature that says that a sedentary lifestyle is healthy for the brain, but a lot of it has found the opposite. I would like to avoid anything that reproduces the neurological effects of being sedentary.
- nonbel 9y ago
  >"I don't know of any literature that says that a sedentary lifestyle is healthy for the brain" Here are two I found: >"More sedentary behavior was strongly predictive of more depressive symptomatology and, unexpectedly, of better cognitive performance." https://journals.humankinetics.com/doi/pdf/10.1123/japa.13.3.294 https://journals.humankinetics.com/doi/pdf/10.1123/japa.13.3... >"Self-reported sedentary behavior was related to better performance on one cognitive task (trails A; p < .05)." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861254/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861254/ Obviously these are "undesirable" results, so you have to look a little bit deeper to find them.
jonhendry18 9y ago
They're using "thinning" in the sense of "thinning hair". Generally lower density would imply fewer neurons and fewer connections. Since this is happening late in life, rather than during the pruning stage of development in youth, this would tend not to be a good thing.
- nonbel 9y ago
  Why do you think this?

by nonbel 9y ago

MikkoFinell 9y ago

Yeah I do believe it makes a difference, because brain atrophy is linked to a range of cognitive impairments, for example strongly correlated with Alzheimer's disease. But you're right on the last point though, about assuming thinner is bad automatically. Heavy and chronic cannabis usage has been linked to an increase in density, but a reduction in total volume, which resulted in a slight overall decrease in IQ. The takeaway from all this being: Cognitive function is affected by a variety of parameters and we got more neuroscience to do still.

nonbel 9y ago
>"Heavy and chronic cannabis usage has been linked to an increase in density, but a reduction in total volume, which resulted in a slight overall decrease in IQ." I wouldn't put much stock into these type of non-quantitative explanations wherein "this makes that go up which makes this go down", etc. Usually the researchers measure a bunch of different things, analyze the data in a bunch of different ways, and only publish whatever is "significant". This works at the single lab level and multi-lab level since the "non-significant" results are considered boring and don't get published. By "usually" I mean this is standard behavior. You can call it p-hacking, file drawer effect, and more recently "forking paths": http://andrewgelman.com/2017/12/29/forking-paths-plus-lack-theory-no-reason-believe/ http://andrewgelman.com/2017/12/29/forking-paths-plus-lack-t... >"Cognitive function is affected by a variety of parameters and we got more neuroscience to do still." Sure, that was the case before these studies were done too though.

always_good 9y ago

> The press release seems to be assuming that thinner is bad automatically. Well, it's not unreasonable. I don't know of any literature that says that a sedentary lifestyle is healthy for the brain, but a lot of it has found the opposite. I would like to avoid anything that reproduces the neurological effects of being sedentary.

nonbel 9y ago
>"I don't know of any literature that says that a sedentary lifestyle is healthy for the brain" Here are two I found: >"More sedentary behavior was strongly predictive of more depressive symptomatology and, unexpectedly, of better cognitive performance." https://journals.humankinetics.com/doi/pdf/10.1123/japa.13.3.294 https://journals.humankinetics.com/doi/pdf/10.1123/japa.13.3... >"Self-reported sedentary behavior was related to better performance on one cognitive task (trails A; p < .05)." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861254/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861254/ Obviously these are "undesirable" results, so you have to look a little bit deeper to find them.

jonhendry18 9y ago

They're using "thinning" in the sense of "thinning hair". Generally lower density would imply fewer neurons and fewer connections. Since this is happening late in life, rather than during the pruning stage of development in youth, this would tend not to be a good thing.

nonbel 9y ago
Why do you think this?