neurodudes

How would you cure blindness, if your phototransducing rods and cones had degenerated - as happens in syndromes that affect millions of people worldwide? A lot of investigators have tried to create very complicated electrical stimulators that drive patterned activity in the retina. You need a power source, a camera of sorts, a computational element, and an array of electrodes that can crank out precise, well-timed current pulses, for a long time. It’s a heroic piece of optical and electrical engineering.

But what if you just made other cells in the retina light-sensitive? Channelrhodopsin and other light-activated ion channels have opened up this new kind of endeavor.

Investigators at Wayne State University, the Pennsylvania College of Optometry, and Beijing University have now done this. They expressed Channelrhodopsin in retinal ganglion cells (RGCs) of mice with photoreceptor degeneration. Remarkably, for months afterwards, the RGCs were able to transmit visual information all the way to visual cortex. In mice without channelrhodopsin, these visual evoked responses were never seen. A very impressive piece of systems bioengineering.

Ectopic Expression of a Microbial-Type Rhodopsin Restores Visual Responses in Mice with Photoreceptor Degeneration
Anding Bi, Jinjuan Cui, Yu-Ping Ma, Elena Olshevskaya, Mingliang Pu, Alexander M. Dizhoor, and Zhuo-Hua Pan

— Ed

Soon machines will obtain higher IQ’s than humans in intelligence tests.
Traditionally the intelligence quotient has been considered the best indicator for scientifically evaluating natural intelligence.
Is this indeed the best way to measure this human capacity? Could a machine emulate a human being solving traditional intelligence tests? If so, could we affirm that a machine possesses an intelligence equivalent to that of a human?
KITBIT explores some of these possibilities.
The ability of KITBIT in symbolic logic problems, in those which verbal intelligence does not come into play, is comparable to that of humans.
On our web-page, TheIQChallenge.com, we challenge our visitors to put KITBIT to the test in solving numerical and logical problems which have the exact same format as traditional intelligence tests used by psychologists.
The KITBIT project develops research in diverse areas of artificial intelligence such as image recognition, creation of models, predictions and data mining.
KITBIT has been designed by a small team of engineers, mathematicians and programmers. Currently we hope to substantially enlarge this team to carry out our ongoing projects.
www.theIQChallenge.com
www.kitbit.com

[This sounds interesting... although it is fine to promote your personal projects here, we'd at least like to know a little bit about how your project is achieving its goal or how your specific algorithms make this different from similar AI endeavors. And please, please always put your name at the bottom of the post! -Neville]

There’s been some work recently on looking at second harmonic generation for optical readout of action potentials… any opinions on this work?

First a brief primer on SHG (from Yuste’s recent Nature Methods paper on fluorescence microscopy):

In SHG, high-infrared light intensity drives the lowest-order nonlinear polarizability of molecules (or groups of molecules) in the specimen so that coherent light of exactly double frequency (or half the wavelength) is emitted. Because the process can occur away from resonance frequencies, there is no absorption of light, thus avoiding complications of photochemistry. This phenomenon is rare and requires, like two-photon excitation, a high concentration of photons at the focal point, something that also gives it optical sectioning. SHG is particularly interesting because it only occurs where chromophores are oriented in noncentrosymmetric arrays, such as chromophores adsorbed to biological membranes or other chemical interfaces. Thus, SHG is perhaps the only optical technique that is truly sensitive to biological membranes, something which makes it ideal for detecting changes in membrane potential. As many important biological processes, such as electrophysiological communication, detection and transduction of external molecules and cell-cell interactions occur at plasma membranes, SHG is likely to become a very useful tool for biologists.

Seed papers:

• Overcoming photodamage in second-harmonic generation microscopy: Real-time optical recording of neuronal action potentials [PNAS Open Access, Feb 2006] , L. Sacconi, D. A. Dombeck, and W. W. Webb
• Imaging membrane potential in dendritic spines [PNAS, Jan 2006] , Mutsuo Nuriya, Jiang Jiang, Boaz Nemet, Kenneth B. Eisenthal, and Rafael Yuste

A forthcoming issue of the journal Neuroscience is devoted to an examination of multidisciplinary approaches to the study of working memory within the field of Cognitive Neuroscience. Although the issue will not be released until late April, a detailed press release is available from the University of Washington at St. Louis.

From the article:

“Multidisciplinary research within cognitive neuroscience has established itself as a promising approach to answering the question of how the mind emerges from the working of the brain” [...] “One of the fields that has gained substantially by successfully combining the theoretical frameworks, methodologies, empirical results and insights of the varied disciplines within cognitive neuroscience, is the study of working memory”

It goes on to describe a “pyramid approach” to multidisciplinary work in this area, which chiefly involves the merging of cognitive psychology, computational science, neuroscience, and cognitive neuropsychiatry.

Shannon Moffett, author of The Three Pound Enigma [book website; Amazon], was kind enough to send us a copy of her book to review. To be honest, when I first took a look at the book, I was pretty sure that — while it might be a great, general-neuroscience-interest book for the public — it would certainly not appeal or be informative for the specialist in our Neurodudes audience. Now, after reading her wonderful book, I realize how wrong I was.

Full review is after the jump.
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