Mouse Runs on Trackball Through Virtual Maze

Posted by John Farrier in Science & Tech, Video Clips on October 15, 2009 at 1:46 pm


(YouTube Link)

Princeton neuroscientist David Tank wanted to study individual neurons in a mouse’s hippocamus as it moves. But the movement of the mouse’s body prevented accurate readings. So he placed the mouse on a giant trackball and let it run through a virtual maze from the video game Quake 2 displayed on screens. Brandon Keim writes in Wired:

Studying individual neurons has been possible in cell cultures, but brains in a dish behave different than real, living brains. Tracking individual neurons in moving animals has been impossible.

“The neurons move back and forth while you’re trying to measure things,” said Tank. “So we developed a way to keep the head fixed in space, but still have mice perform behaviors that are usually studied in mice running through a maze.”

Tank’s team designed an apparatus in which a mouse, its head firmly held in a metal helmet, walks on the surface of a styrofoam ball. The ball is kept aloft by a jet of air, so that it functions like a multidirectional treadmill. Around it are sensors taken from optical computer mice, which read the ball’s movement as the mouse runs.

Those readings were the input for the researchers’ virtual reality software — a modified version of the open source Quake 2 videogame engine, tweaked to project an image on a screen surrounding the mouse. Tank called it “a mini-IMAX theater.”

Link via Popular Science

 
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Dead Salmon + MRI = Red Herring

Posted by Miss Cellania in Science & Tech on September 20, 2009 at 12:47 pm

Neuroscientist Craig Bennett bought a salmon to test an fMRI machine and work out some protocols.

So, as the fish sat in the scanner, they showed it “a series of photographs depicting human individuals in social situations.” To maintain the rigor of the protocol (and perhaps because it was hilarious), the salmon, just like a human test subject, “was asked to determine what emotion the individual in the photo must have been experiencing.”

The salmon, as Bennett’s poster on the test dryly notes, “was not alive at the time of scanning.”

Those involved got a laugh out of the situation, until the scans came back and showed that activity was detected in different areas of the brain when the fish was “shown” the pictures. Remember, the fish was dead.

The result is completely nuts — but that’s actually exactly the point. Bennett, who is now a post-doc at the University of California, Santa Barbara, and his adviser, George Wolford, wrote up the work as a warning about the dangers of false positives in fMRI data. They wanted to call attention to ways the field could improve its statistical methods.

Which is not to say that scans aren’t a useful research tool, but that they must be carefully monitored to avoid false positive results. Link -via reddit

 
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Remembering Without Knowing It

Posted by Queuebot in Science & Tech on September 11, 2009 at 3:12 am

Ever notice when you walk into a room that you know something has changed and it takes a moment to realize what’s missing?  Your eyes may know the answer before you do, as simple memory games have shown that your eyes focus on the correct answer before you are able to identify it. 

By observing the hippocampus part of the brain, which is responsible for traditional memories, neuroscientists Deborah Hannula and Charan Ranganath noted that persons giving incorrect answers still had increased activity when their eyes observed the correct answer.  The prefrontal cortex (PFC), which is responsible for decision making, mirrored the behavior of the hippocampus.

So your hippocampus may have made the connection that the napkin holder is missing, but your PFC must get involved for you to realize it. “The idea is that recollection may be a two-stage process,” Hannula says. “First you have retrieval of the memory, and then you have a conscious appreciation of what’s been retrieved.”

The study provides strong support for the idea that the hippocampus can process relational memories without a person being aware of it, says Boston University neuroscientist Howard Eichenbaum.

Link

From the Upcoming ueue, submitted by OddNumber.

 
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Problem with Close-Talking? Blame the Brain

Posted by Queuebot in Science & Tech on September 4, 2009 at 12:40 pm

Why is it so uncomfortable to stand really close to a stranger? Sure, there are the potentially icky things. Sometimes an elevator car is so crowded that you can smell a fellow rider’s shampoo or chewing gum (or worse). But even when a stranger is perfectly groomed, it’s usually a bit revolting to be pressed against him in public. Why?

A team of scientists from Caltech put SM through a series of tests in which they asked her to indicate the position at which she became uncomfortable as another woman, a researcher, approached her. SM’s preferred personal distance was 1.1 ft. (0.34 m), about half the preferred distance (2 ft., or 0.64 m) of a group of comparison subjects. At 1 ft., you can easily discern whether someone showered after the gym — although in the lab experiment, the Caltech researchers made sure the experimenter was well-scrubbed and had just chewed gum before interacting with SM.

Link

From the Upcoming ueue, submitted by Rossy21.

 
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Brain Surgery Simulator

Posted by John Farrier in Medicine, Video Clips on September 2, 2009 at 3:46 pm


(YouTube Link)

This CBC news story describes a brain surgery simulator that doctors in Halifax, Canada use for practice before cutting open real patients. It simulates not a generic human brain, but the brain of the specific patient:

First, patient data from functional magnetic resonance imaging (fMRI) is rendered into a 3-D, high-resolution model of an individual’s brain. After the model is loaded into the system, doctors can touch and manipulate tumors and other virtual objects on screens in real time using a physical instrument resembling a scalpel. The instrument has six degrees of freedom and re-creates the force-feedback of the real tool and the varying resistance of tissue in brain regions with differing toughness. Meanwhile, photo-realistic on-screen imagery shows the simulated surgery, including bleeding and pulsing gray matter.

Link via Popular Science

 
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Mind-Reading Computer Takes Images Straight out of Your Brain

Posted by Alex in Medicine, Science & Tech on December 12, 2008 at 4:29 am

Japanese scientists at the ATR Computational Neuroscience Labs have successfully built a machine that can read your mind – or at least getting images straight from your brain:

A Japanese research team has revealed it had created a technology that could eventually display on a computer screen what people have on their minds, such as dreams.

Researchers at the ATR Computational Neuroscience Laboratories succeeded in processing and displaying images directly from the human brain, they said in a study unveiled ahead of publication in the US magazine Neuron.

While the team for now has managed to reproduce only simple images from the brain, they said the technology could eventually be used to figure out dreams and other secrets inside people’s minds.

Link | Article at Pink Tentacle – via Gizmodo

 
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