Link to Nature Physics article
Thursday, September 25, 2008
Nature Physics published a news article this week on the fascinating subject of metamaterials. These materials are novel in that the have a negative refractive index or the bend light the "wrong" way. Two groups of researchers speculate on how these materials could be used to make hidden doorways not unlike the magical platform 9 3/4 from the Harry Potter story. While it will still be some time before we have a real chance at creating a hidden doorway large enough for a person to walk through the possibility is enthralling.
Friday, September 19, 2008
In the current issue of Nature Neuroscience, a paper by T. Heck et al, described the dynamics of dendritic spine turnover and the role this plays the in the restructuring of interneuronal connections following injury and altered sensory input. In the experiment, retinal lesions made to mice led to deafferented zones in the lesion projection site of the visual cortex. These zones were observed to undergo increased spine turnover using two-photon microscopy. The rate of turnover, about 3.5x increase, which thought to be related the functional reorganization to stimulation of retinal areas surrounding the lesion site. To test this idea complete retinal lesion were made to both eyes to eliminate all retinal input. In this condition, there was no significant increase in turnover rate of the visual cortex compared to control animals.
Furthermore, in animals with with a single lesion, it was found that the turnover rate led to a replacement of ~90% of spines in the affected cortical regions. Also, these spines were more likely to be stabilized for the duration of the experiment, lending additional support for their role in functional reorganization.
These data suggest that spine turnover plays an important role in functional reorganization of cortex due to sensory stimulation.
Link to Nature Neuroscience article
Thursday, September 18, 2008
The open source model primarily used in the software community has now made it way into biomedical engineering via the field of prosthetics. With the advancement of emergency medicine, many less lives are lost during combat than in the past. However, the downside to this is that soldiers who would have died, now survive with grievous and dehabilitating injuries.
To make the picture even bleaker, the total number of persons in the American population who need prosthetics is small and so is the profit margin. This has led to minimal R&D in the field and those who need these devices must make do , or tinker on their own.
In reality, many garage inspired prosthetics advances have occurred but taking them beyond that point has proved troublesome due to complicated laws, along with industry practices.
In hopes of solving this dilemma and bringing greater functionality to prosthetics the Open Prosthetics Project (OPP)was born. This project was founded by a group of friends who owned their own R&D firm "Tackle Design". The beginnings of the project began when one of the members who was deployed in Iraq was the victim of an IED and lost most of his right arm.
When he received is prosthetic he was unimpressed, to say the least. His "myoelectric" arm was state of the art and more aesthetic pleasingly than the traditional hook, but ultimately not very useful. The hook while crude in appearance and function offers much more in the way of usefulness than the newer myoelectric devices which are barely strong enough to open a door.
They group realized that the only way the could make a change in the world was prosthetics would be to make their designs public and speed up the process of development. With that thought the OPP was brought to life. It's "hope is to use this and our complementary sites to create a core group of lead users and to speed up and amplify the impact of there innovations in the industry."
Link to Wired article
Link to SciAm article
Thursday, September 11, 2008
Yesterday CERN, the European Council for Nuclear research, announced the commencement of the world's largest particle accelerator, the Large Hadron Collider. This new testament to the marvels of human engineering will begin anew on the quest to discover the elusive Higgs boson particle, which is though to bestow mass on all other particles. The conditions created by this newest of atom smashers are suppose to replicate those present just a trillionth of a second after time zero or the Big Bang. Although everyone is all a buzz about the turning on of the Hadron it will still be some time until any analyzable data is generated. Still the hopes are high and many in the field believe that this machine will reveal the answers to fundamental questions about how the universe was formed.
Not to be completely overshadowed, the Fermilab, formerly the title holder of world's largest atom smasher, has recently postulated that there may be a fourth type of neutrino, which travels interdimensionally. String theory has proposed that our reality is a 4-dimensional "brane" inside a 10 dimensional "hulk", and the physicists at Fermilab believe this new category of neutrino is able to travel from the bran through the bulk and back again. This new particle would account for an otherwise odd observation of a high number of neutrinos at lower enegry levels. ( low for physicists being 475 million electron volts).
NYTimes article about Hadron
Thursday, August 28, 2008
Wednesday, August 27, 2008
In a recent study, Fehr et al described the sharing attitudes of children ages 7-8. This experiment made use of a paradigm similar to the one used by neuroeconomics to study decision making and fairness in adults. The experimenters presented the children with candy and a picture of another child. The child was told to divide the candy between themselves and the pictured child. Largely all of the children chose to distribute the sweets equally. In comparison, children 3-4 are very much self-centered when it comes to food and will not share food at all. However, children at this age do show some signs of altruism, such as instrumental helping. In others words opening a door or helping to carry a heavy object.
Also, of noted interest, the authors mention that chimpanzees display no "other regarding preferences". Thus, it seems a closest evolutionary cousins have not developed an extensive notion of sharing.
In neuroeconomics, a typical paradigm involving the allocation of resources is used to study decision making. The experiment goes you and another individual are to split a sum of money. One individual is told to decide which percentage of x$ you get and he gets. You then get to accept the offer or decide that neither of you receives anything. The results of this study were if people felt they were being cheated they would forgo any sort of payment to spite the other particpant. Logically this is not in their best interest. Regardless of what is offered you might as well accept and be better off than you were before. This studies were done in fMRI and scans showed that "unfair" offers elicited heightened activity in the anterior insula, as well as the dorsolateral prefrontal cortex.Activity of the insula, known for its involvement in emotion suggests that decisions, are not purely cognitive in origin. This experiments illustrates the notion that people are not rational maximizers, and sometimes "reason doesn't matter".
Link to Nature article
Link to neuroeconomics paper
A new book Head Cases, reviewed in Nature Neuroscience, addresses the personal impact of traumatic brain injury (TBI). The overall purpose is to bring to light the reality of the overwhelming obstacles faced by sufferers of TBI. This is a noble effort given that many researchers are susceptible to getting caught up in the minutia of their work and lose sight of the grander picture. Especially those of us just starting who are often torn between altruism and career ambitions. However, according to Masud Husain, neurobiologist at UCL and Nature reviewer, the book deals to far in philosophical issues and musing that are not well integrated. Additionally, the author takes grievances with neurosurgeons and scientists, in a form of ranting that is misplaced. All in all, it seems the book aim is well meant, but took a few too many tangents that detracted from its goal. Nonetheless, it succeeds in that by its mere existence we, neuroscientists, are reminded to look up from our laboratory bench and remember why we are there.
Link to Nature Neuroscience review