jm + brain + biology   5

Brain Cells Share Information With Virus-Like Capsules - The Atlantic
...a gene called Arc which is active in neurons, and plays a vital role in the brain. A mouse that’s born without Arc can’t learn or form new long-term memories. If it finds some cheese in a maze, it will have completely forgotten the right route the next day. “They can’t seem to respond or adapt to changes in their environment,” says Shepherd, who works at the University of Utah, and has been studying Arc for years. “Arc is really key to transducing the information from those experiences into changes in the brain.”

Despite its importance, Arc has been a very difficult gene to study. Scientists often work out what unusual genes do by comparing them to familiar ones with similar features—but Arc is one-of-a-kind. Other mammals have their own versions of Arc, as do birds, reptiles, and amphibians. But in each animal, Arc seems utterly unique—there’s no other gene quite like it. And Shepherd learned why when his team isolated the proteins that are made by Arc, and looked at them under a powerful microscope.

He saw that these Arc proteins assemble into hollow, spherical shells that look uncannily like viruses. “When we looked at them, we thought: What are these things?” says Shepherd. They reminded him of textbook pictures of HIV, and when he showed the images to HIV experts, they confirmed his suspicions. That, to put it bluntly, was a huge surprise. “Here was a brain gene that makes something that looks like a virus,” Shepherd says.

That’s not a coincidence. The team showed that Arc descends from an ancient group of genes called gypsy retrotransposons, which exist in the genomes of various animals, but can behave like their own independent entities.* They can make new copies of themselves, and paste those duplicates elsewhere in their host genomes. At some point, some of these genes gained the ability to enclose themselves in a shell of proteins and leave their host cells entirely. That was the origin of retroviruses—the virus family that includes HIV.
brain  evolution  retroviruses  viruses  genes  arc  gag  proteins  memory  biology 
7 days ago by jm
Cordyceps even creepier than at first thought
Hughes’s team found that fungal cells infiltrate the ant’s entire body, including its head, but they leave its brain untouched. There are other parasites that manipulate their hosts without destroying their brains, says Kelly Weinersmith from Rice University. For example, one flatworm forms a carpet-like layer over the brain of the California killifish, leaving the brain intact while forcing the fish to behave erratically and draw the attention of birds—the flatworm’s next host. “But manipulation of ants by Ophiocordyceps is so exquisitely precise that it is perhaps surprising that the fungus doesn't invade the brain of its host,” Weinersmith says. [....]

So what we have here is a hostile takeover of a uniquely malevolent kind. Enemy forces invading a host’s body and using that body like a walkie-talkie to communicate with each other and influence the brain from afar. Hughes thinks the fungus might also exert more direct control over the ant’s muscles, literally controlling them “as a puppeteer controls as a marionette doll.” Once an infection is underway, he says, the neurons in the ant’s body—the ones that give its brain control over its muscles—start to die. Hughes suspects that the fungus takes over. It effectively cuts the ant’s limbs off from its brain and inserts itself in place, releasing chemicals that force the muscles there to contract. If this is right, then the ant ends its life as a prisoner in its own body. Its brain is still in the driver’s seat, but the fungus has the wheel.
biology  gross  cordyceps  fungi  fungus  ants  zombies  infection  brain  parasites 
8 weeks ago by jm
_Could a Neuroscientist Understand a Microprocessor?_
'There is a popular belief in neuroscience that we are primarily data limited, that producing large, multimodal, and complex datasets will, enabled by data analysis algorithms, lead to fundamental insights into the way the brain processes information. Microprocessors are among those artificial information processing systems that are both complex and that we understand at all levels, from the overall logical flow, via logical gates, to the dynamics of transistors. Here we take a simulated classical microprocessor as a model organism, and use our ability to perform arbitrary experiments on it to see if popular data analysis methods from neuroscience can elucidate the way it processes information. We show that the approaches reveal interesting structure in the data but do not meaningfully describe the hierarchy of information processing in the processor. This suggests that current approaches in neuroscience may fall short of producing meaningful models of the brain.'

via Bryan O'Sullivan.
via:bos  neuroscience  microprocessors  6502  computers  hardware  wetware  brain  biology  neural-systems 
june 2016 by jm
How big an issue is the nausea problem for Virtual Reality products? - Quora
Sadly (because I want a “holodeck” as much as the next red-blooded geek) - I don’t think it’s possible to make a VR system that both delivers the experience that everyone wants - and doesn’t make a sizeable proportion of the population so sick that they’ll never want to do it again. For the people who can stomach the display - my major concern is that the US Navy studies show that there is some disorientation that might persist long after finishing your game…so driving a car while “under the influence” of post-VR disorientation is probably as dangerous as drunk-driving.

If these devices are in pretty much every home - then there are huge problems in store for the industry in terms of product liability. There have been plenty of warnings from the flight simulation industry - there are no excuses for not reading the Wikipedia article on the subject. If people are driving “under the influence” and the VR companies didn’t warn them about that - then they’re in deep trouble.

IMHO, these consumer-grade VR devices should be carefully studied and if they do cause possible driving impairment, they should be banned until such time as the problems can be fixed…which may very well be “never”. Sorry to be the bearer of bad news.


(via Tony Finch)
holodeck  vr  oculus-rift  hmds  nausea  head-mounted-displays  biology  brain  flight-simulation 
may 2016 by jm
Hangovers aren't caused by dehydration, low blood sugar, or acetaldehyde / Boing Boing
The [now-]leading theory implicates a specific gamma aminobutyric acid (GABA) and a complementary brain receptor, "that responds to low concentrations of ethanol, as produced by one glass of wine, in the brain."
hangovers  booze  brain  biology  biochemistry  gaba  ethanol  alcohol 
january 2016 by jm

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