growlix's comments

growlix | 4 years ago | on: Man can change his pupil size on command

It seems like there are a lot of commenters claiming to be able to do the same thing who didn't read the abstract:

"...various indirect mechanisms possibly mediating this phenomenon were tested: accommodation, brightness, increases in arousal by increased mental effort. None of these behavioral tests could support an indirect strategy as the mode of action"

growlix | 5 years ago | on: Behavioral nudges reduce failure to appear for court

The effect of the nudge is definitely the main story here, but the redesigned summons form (Figure 1) seems like a pretty good example of the importance of communication design. While there's certainly still room for improvement, the new forms seem much easier to understand.

growlix | 5 years ago

Anecdotally, this stereotype seems to exist in the United States as well.

When it comes to data, the 2016 National Household Education Survey by the National Center for Education Statistics shows that 51% of parents selected "A desire to provide religious instruction" as an "important" reason for homeschooling their children, and 67% selected "A desire to provide moral instruction" as an "important" reason for homeschooling [0, in bar plot form; 1, original data].

[0] https://responsiblehomeschooling.org/research/summaries/reas... [1] https://nces.ed.gov/pubs2017/2017102.pdf

growlix | 5 years ago

An interesting perspective summarized here [0] is that the bombings were not just unnecessary to end the war and were conducted as a show of force to the Soviets. They were conducted in an attempt to end the war ASAP, before a planned Soviet ground invasion of Japan so that the US wouldn't have to share control over post-war Japan with the Soviets.

[0] https://www.globalresearch.ca/the-real-reason-america-used-n...

growlix | 5 years ago

Yup. Post got flagged too. I assume because it's "political", but in my experience HN is very interested in civil liberties.

growlix | 7 years ago

Totally reasonable. I was more (be/a)mused than suspicious. I'm excited to see what gets funded!

growlix | 7 years ago | on: Brain cells that track location in space appear to also count beats in time

I see a lot of child comments using "spatial" to refer to multiple distinct concepts: 1) coordination and movement in space, 2) visuospatial skills (i.e. intuition for 2D and 3D geometry), and 3) navigation. While many tasks make use of multiple of these capabilities simultaneously, there are clear behavioral and neuroanatomical dissociations between them (thought slightly less so between 1 and 2).

Coordination of movement in space (for example something like grasping an object) is more dependent on parietal cortex & the dorsal visual stream (the so-called "where" pathway), and the cerebellum.

"Visuospatial skill", as typified by tasks like mental object rotation, is more ascribable to temporal cortex & the ventral visual stream (the so-called "what" pathway, responsible for object recognition). However, it often requires both ventral and dorsal visual cortex.

Navigation is hippocampus-dependent. However, the hippocampus is not a "GPS". I cannot emphasize this strongly enough. It is a hub for integrating and associating disparate information from across the brain in order to form representations of and the relationships between behaviorally-relevant states. This explains why the hippocampus is also involved in "navigating" abstract state spaces, for example turn-based game states [0] or auditory frequency [1], when they're behaviorally relevant. It gets analogized as a GPS because 1) most of the research involves spatial tasks, so space is the behaviorally-relevant dimension, 2) a certain Nobel Prize winner does not feel the need to update his theory, and 3) "Hippocampus = GPS" is too sexy and intuitive of an analogy, especially for the lay press.

The idea of the hippocampus as an "associative engine" also helps unify its seemingly disparate roles in "navigation" and memory when you consider that a memory is just information from disparate brain areas that's been associated via temporal correlation because of its behavioral relevance. It also explains why researchers observe "place cells" and "time cells" and "head direction cels" and "eye position cells": because these variables are behaviorally relevant (i.e. important for maximizing reward) in the task the animal is performing.

[0] https://onlinelibrary.wiley.com/doi/pdf/10.1002/hipo.22523

[1] https://www.ncbi.nlm.nih.gov/pubmed/28358077

growlix | 8 years ago | on: Theranos Misled Investors and Consumers Who Used Its Blood Test

On the "Delusion <-> Con Artist" continuum, I'm inclined to think she's more on the delusion end. If your intent is to defraud, you'd want to avoid a domain that's 1) scientifically accountable, and 2) subject to heavy oversight and regulation. She seems smart enough to know that.

This Vanity Fair piece provides a fair amount of character background: https://www.vanityfair.com/news/2016/09/elizabeth-holmes-the...

growlix | 8 years ago

In addition to the mechanisms described by others, it seems that antibiotics alter the microbiome in a manner that affects nutrient metabolism.

source: https://www.nature.com/articles/nature11400

abstract: Antibiotics administered in low doses have been widely used as growth promoters in the agricultural industry since the 1950s, yet the mechanisms for this effect are unclear. Because antimicrobial agents of different classes and varying activity are effective across several vertebrate species, we proposed that such subtherapeutic administration alters the population structure of the gut microbiome as well as its metabolic capabilities. We generated a model of adiposity by giving subtherapeutic antibiotic therapy to young mice and evaluated changes in the composition and capabilities of the gut microbiome. Administration of subtherapeutic antibiotic therapy increased adiposity in young mice and increased hormone levels related to metabolism. We observed substantial taxonomic changes in the microbiome, changes in copies of key genes involved in the metabolism of carbohydrates to short-chain fatty acids, increases in colonic short-chain fatty acid levels, and alterations in the regulation of hepatic metabolism of lipids and cholesterol. In this model, we demonstrate the alteration of early-life murine metabolic homeostasis through antibiotic manipulation.

growlix | 8 years ago

Also that "brainwaves" have meaning beyond the behavior, brain region, and context in which they're being examined.
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