Archive for June, 2006
How long before hand-held TMS hits the streets for dubious recreational purposes?
Sacks and Siegel in Nature report on the recovery of steroscopic vision in a patient suffering from stereo blindness for 50 years. If cortex is indeed that plastic, I can’t help but ask, “why stop with only 3-dimensions?” Besides being cool, there might even be practical applications in training individuals to be able to see objects in spaces of four dimensions and higher. Data about a complex dynamical system might be handled more easily if its multidimensional state-space can be directly grasped by the human visual system. Things might “pop-out” of a data set that might otherwise be difficult to detect.
Questions arise as to how to train someone to pull this off. What does it even mean for vision to take place in higher dimensions? It might be useful to think about the geometry of photography for a bit here. The photography of a three-dimensional object involves a projection onto a two-dimensional surface. Stereoscopy is accomplished by integrating projections from a single 3-D object onto two different 2-D surfaces. By analogy, photography in the fourth dimension would involve the projection of a hypersolid onto points in a 3-D volume. 4-D steroscopy (”Hyperscopy”?) would then involve, I guess, the integration of projections of a single 4-D object onto points in different 3-D volumes.
One might question whether a person, being only 3-D, could possibly accompish hyperscopy, given that our irritable surfaces–our retina, etc.–are essentially only 2-D. The key to realize is that the dimensionality of our sensor arrays is potentially surmountable. The points in, e.g. our retina, can be mapped onto points in a volume–this is precisely what enables plain-old steroscopy in the first place. And our brains are capable of representing higher-dimensional state-spaces: gustory state-space is at least four-dimensional and olfactory state-space is six-.
Here then, in theory, is how to train someone to be hyperscopic. First, off, the 4-D objects are going to have to be computer generated. Second, computer simulated 3-D retina–3-D arrays of voxels–will be projected onto by the 4-D objects. Third, information from each of these voxels will be projected–via video goggles–to a dedicated portion of the person’s visual field. That is, the visual field will be partitioned into the same number of subregions as there are voxels in the 3-D computer-simulated retina. Fourth, equip the person with some means of rotating the 4-D objects (since having control over inputs seems to be important in perceptual plasticity). Fifth, train the person to perform 4-D object recognition tasks. Objects in the training set should include objects that can only be distinguished by their 4-D charactersitics.
If such a training regime could be successful executed, would it be 4-D vision? Would the hyperscopist have 4-D qualia?
Chase Wrenn of Conditional Material sent this to me:
Brain Hammer recipe
As served at the Julliard, a whiskey bar in Taegu, Korea.
1 1/2 oz peach schnapps
1/2 oz Bailey’sÂ® Irish cream
1 dash grenadine syrup
1/4 oz BacardiÂ® 151 rum
Use a narrow, stemmed glass that’s not too tall. Pour peach schnapps in first, then using an inverted spoon, pour on a layer of Bailey’s Irish cream. Slowly drip grenadine through the Bailey’s, creating a “brain” effect at the bottom of the glass. Put another, thin layer of Bacardi 151 rum on top.
Fill a spoon with 151, light the alcohol, then carefully drip the burning rum down a long knife so that it lights the rum in the glass. While burning, drink entire beverage through a straw without stopping.
Decreased frontal-lobe efficiency is associated with negative thinking and depression. Which way, I wonder, do the arrows of causation point? Posted in Cog News:
“First, the people with late-onset depressive symptoms showed poorer performance on executive function tests than those with early onset depression.” “Executive decline” is a normal part of ageing linked to decreased efficiency in the brain’s frontal lobes. Typical signs of executive decline include disinhibition, rigid thinking, inattention and a decline in working memory.
“Second, we saw that executive decline was associated with rumination — a tendency for repeated negative thinking patterns — among those with late-onset depression,” says von Hippel, who is associate professor of psychology at the University of New South Wales. “We saw no such link among those who had early-onset depression.”
“Third, the link between executive decline and late onset depression was brought about by their joint association with rumination. That is, executive decline was only associated with late-onset depression to the degree that it led people to ruminate. When executive dysfunction did not lead to rumination, it did not predict late-onset depression.
“Clinical rumination is like problem-solving gone awry — it’s a wrong turn,” says Dr von Hippel. “Looking inward and being reflective is a useful thing to do, especially when negative events happen in our life. But if we get stuck in a pattern of saying ‘why me?’ there’s a risk that we can spiral into a pathology. Instead of solving the problem we just stew in it.”
Danger! Danger! My robot page is up and functional. Bzzt!
Irving Biederman will get you high. With knowledge.
The “click” of comprehension triggers a biochemical cascade that rewards the brain with a shot of natural opium-like substances, said Irving Biederman of the University of Southern California. He presents his theory in an invited article in the latest issue of American Scientist.
“While you’re trying to understand a difficult theorem, it’s not fun,” said Biederman, professor of neuroscience in the USC College of Letters, Arts and Sciences.
“But once you get it, you just feel fabulous.”
The brain’s craving for a fix motivates humans to maximize the rate at which they absorb knowledge, he said.
“I think we’re exquisitely tuned to this as if we’re junkies, second by second.”
Biederman hypothesized that knowledge addiction has strong evolutionary value because mate selection correlates closely with perceived intelligence.
Only more pressing material needs, such as hunger, can suspend the quest for knowledge, he added.
The same mechanism is involved in the aesthetic experience, Biederman said, providing a neurological explanation for the pleasure we derive from art.
“This account may provide a plausible and very simple mechanism for aesthetic and perceptual and cognitive curiosity.”
Biederman’s theory was inspired by a widely ignored 25-year-old finding that mu-opioid receptors â€“ binding sites for natural opiates â€“ increase in density along the ventral visual pathway, a part of the brain involved in image recognition and processing.
The receptors are tightly packed in the areas of the pathway linked to comprehension and interpretation of images, but sparse in areas where visual stimuli first hit the cortex.
Biederman’s theory holds that the greater the neural activity in the areas rich in opioid receptors, the greater the pleasure.
N.A.S.A. A.N.T.S., Nasa’s Autonomous Nanotechnology Swarm. Put self-reproductive junk in space!
A robot designed to crawl through the human gut by mimicking the wriggling motion of an undersea worm has been developed by European scientists. It could one day help doctors diagnose disease by carrying tiny cameras through patients’ bodies.
Evolutionary Robotics (ER) is a methodology that uses evolutionary algorithms to develop controllers for autonomous robots. To better understand robot evolution, I have created LegoMindstorm SexBots using NQC programming as part of an Independent Study under Dr. Tony Chemero at the Artificial Intelligence labs at Franklin & Marshall College. The robots exchange genetic code, i.e. their genome, via infrared, creating a new robot generation. The following pages explain the design and construction of the SexBots, give an explanation of the programming platform, and also provide a description of the genetic algorithmic program and its exchange. Further, discussion of application and implication of evolutionary robotics will be detailed on additional pages.
The sexed robots are autonomous wheeled platforms fitted with nylon genital organs, respectively male and female. They are programmed to explore their environment, occasionally entering a “in heat” mode, where they will try and locate a partner in the same state. If a partner is located, the robots will attempt to mate.
The first aim of Encephalon is to get contributions from as many neuroscience bloggers as possible, so I’d like the list of neuroscience blogs on the right to get shorter, and the list of contributors to get longer. The overall aim of the carnival is to find high quality writing about neuroscience, and to provide a resource of neuroscience blogs.
The first edition of Encephalon will be posted on the neurophilosopher’s blog on 3rd July, 2006.
Re: The Synapse:
I — and many of the other neuroscience-related bloggers on this site — sense a strong need for a neuroscience carnival — a way to regularly collect all of our valuable posts in a predigested form. So I am asking you to submit your best neuroscience posts over the next two weeks to me for the first “The Synapse” (a neuroscience carnival) to be published on June 25th.