31 augustus 2007
The Matrix (algebra)
ENTER THE MATRIX
If You want to delve into EEG signal analysis basics - and who would not ?- a good working knowledge of essential vector and matrix algebra is a necessity. If, like me, that knowledge is since shooltime, deeply burried somewhere into the shelves and windings of temporal cortex this very useful book will help You refresh it. It's Bronson without the movie...
PREFACE
In this appealing and well-written text, Richard Bronson gives readers a substructure for a firm understanding of the abstract concepts of linear algebra and its applications. The author starts with the concrete and computational, and leads the reader to a choice of major applications (Markov chains, least-squares approximation, and solution of differential equations using Jordan normal form). The first three chapters address the basics: matrices, vector spaces, and linear transformations. The next three cover eigenvalues, Euclidean inner products, and Jordan canonical forms, offering possibilities that can be tailored to the instructor's taste and to the length of the course. Bronson's approach to computation is modern and algorithmic, and his theory is clean and straightforward. Throughout, the views of the theory presented are broad and balanced. Key material is highlighted in the text and summarized at the end of each chapter. The book also includes ample exercises with answers and hints. With its inclusion of all the needed features, this text will be a pleasure for professionals, teachers, and students.
Contents
PREFACE, 1. MATRICES, 2. VECTOR SPACES, 3. LINEAR TRANSFORMATIONS, 4. EIGENVALUES, EIGENVECTORS, AND DIFFERENTIAL EQUATIONS, 5. EUCLIDEAN INNER PRODUCT, APPENDIX A: DETERMINANTS, APPENDIX B: JORDAN CANONICAL FORMS, APPENDIX C: MARKOV CHAINS, APPENDIX D: THE SIMPLEX METHOD, AN EXAMPLE, APPENDIX E: A WORD ON NUMERICAL TECHNIQUES AND TECHNOLOGY, ANSWERS AND HINTS TO SELECTED PROBLEMS, INDEX
BCI data from Pakistan
The following EEG datasets were used in this research. All downloads are in Matlab MAT format... jump here
30 augustus 2007
Neuronal Emotions
EMTIONALLY YOURS...
More and more psychiatrists who get involved in neurophysiology express their desire to explore the neuronal limbic core in more fundamental depth. Especially for those (and for JR, a very good friend especially) the editors of Nature Neuroscience, using their telepathic ability managed to assemble a special edition to attend to their wishes.
Individual quality of life depends on the ability to experience emotions appropriately and to regulate them in response to stressful events. In addition, depression and anxiety are a substantial public health burden. This special focus contains four reviews and a perspective from leaders in the field, who discuss how the brain regulates emotions, how this regulation becomes impaired by disorders of emotion and which therapies may be effective in treating these disorders.
28 augustus 2007
Cognition, Brain and Consciousness
A new handbook on Cognitive Neuroscience
"Masterfully organized and comprehensive in its coverage, this textbook will surely be THE introduction to cognitive neuroscience. The contributing authors are highly accomplished experts, and details are deftly selected to illustrate principles as well as to launch the curious reader into the exciting but vast realm of the nervous system. Anatomy, sometimes the bane of introductions to the brain, is gracefully interwoven on a need-to-know basis. In a clever use of IT, the accompanying website provides videos of human patients as well as powerpoint slides for anatomy and physiology. The companion website will be updated regularly with the latest results, and in the open-source tradition, website ideas are solicited from imaginative readers. A powerful pedagogical achievement, and a boon for both the novice and the advanced student."--
Patricia Smith Churchland, ChairUC President's Professor of PhilosophyUniversity of California San Diego, USA
"Comprehensive, authoritative and beautifully illustrated, this is a superb introduction to cognitive neuroscience. It is ideally suited as a text to accompany an undergraduate or graduate course. The depth and sophistication of its treatment of key topics make it more than a mere introductory text, though, and it can be read with profit by all with an interest in how the brain supports cognition, whether student or established researcher."--Michael D. Rugg, Center for the Neurobiology of Learning and Memory at the University of California, Irvine, USA
The Alzheimer Plaque
As close as one can get !
This nebula-like object surrounded by thousands of points of light is an image not of astronomical origin but from the inner space of the brain—the brain of aging Tg2576 mice, to be precise. This famous mouse, which overexpresses the human APP "Swedish" mutation for familial Alzheimer disease, loses synapses and develops plaques that closely resemble the pathological Aβ plaques found in the brains of human AD patients at autopsy. One such plaque is shown in yellow here. The smaller red and green objects represent presynaptic (synapsin 1) and postsynaptic (PSD-95) components. The depletion of synapses evident within and near the Aβ plaque could account for the cognitive dysfunction in AD. This image was acquired using Array Tomography, a powerful new 3D imaging method developed recently at Stanford University. View/download a higher-quality version. Video credit: Stephen J. Smith in collaboration with Kristina Micheva (Stanford).
Credits:
Smith Lab (Stanford)
Kristina Micheva
Nancy O’Rourke
Stephen J Smith
Hyman Lab (Harvard)
Brad Hyman
27 augustus 2007
Research Channel
A HUGE repositorium of top-of-the-bill expert knowledge. This will keep You busy for some time..... (you have been warned !)
FABULOUS...
MS-BCI ?
Close Your Windows. Bill gates is moving with BCI power
Hear (and see) on Video what Brendan Allison (Microsoft) has to say on BCI.
Video (needs IE 6.0) will not work with Firefox (this is indeed a Microsoft production :-)
Artificial neural networks: The Movie
In a Neurodimensianal theatre not far from You
If You like a bit more professional intro try the book.
Neural and Adaptive Systems: Fundamentals Through Simulations
by Jose C. Principe Neil R. Euliano W. Curt Lefebvre Copyright 2000 © John Wiley & Sons, Inc. .
26 augustus 2007
Sightseeing McGill's Brain
Take a Tour at McGill. Famous for Brains.
Very general public stuff but nicely presented.
Also for more groundbreaking news
Researchers at McGill University’s Montreal Neurological Institute (MNI) have pinpointed the previously unknown part of the human brain responsible for perceiving and storing ordered visual information. This capacity is fundamental to high-level planning and is unique to humans and other primates like monkeys and chimpanzees, said study co-author Dr. Michael Petrides, director of the MNI’s Neuropsychology/Cognitive Neuroscience Unit.
"Our capacity to plan and manipulate information in the mind is dependent on our ability to take in the precise order of things." continued Petrides. "Dogs and cats and rats and squirrels have a lot of memory capacity, but their brains probably do not have the ability to capture the precise order of sequences of items. Approximate order is perceived based on salient features such as the stronger impression of the most recently seen item."
The study, co-authored by postdoctoral research fellow Céline Amiez and Petrides, was pre-published online in The Proceedings of the National Academy of Sciences during the week of August 13. In the study, seventeen volunteer test subjects were scanned using functional magnetic resonance imaging (fMRI) as they were shown sequences of abstract black and white images.
"Immediately after they were shown the first sequence of images, they were shown the first and the second image or the third and the first and so on." explained Petrides. "Then they had to make a judgment about which image came earlier." The researchers monitored activity within the brain during performance of this task and thus were able to localize the specific area within the mid-dorsolateral prefrontal cortex (DLPFC) responsible for taking in and maintaining the precise order of visual stimuli or events perceived by the observer.
The abstract Mondrian-like designs used in the study were chosen specifically because they could not be easily verbalized, to filter out the effects of verbal memory. "We wanted to study the capacity of the mind to hold things that you do not put into your verbal memory," said Petrides. "Interestingly, this capacity is not very large. If you can put the items into words, you can manage seven or eight, but if they're abstract visuals, it's more like four or five."
Though the study was conducted from a pure research perspective, some practical spin-offs can be expected, said Petrides. Their findings are relevant to the understanding of neurological problems like attention deficit disorder, and the study's methodology can be used to assist surgeons to map and avoid the area during surgical procedures.
Neuroscience Institute on Medscape
Interesting stuff on depression, insomnia , anhedonia.....etc.
Anhedonia as a Preclinical Model for Major Depression
Gary Evoniuk, Ph.D. GSK Research & Development
All currently marketed antidepressants are thought to work via monoaminergic mechanisms. The two most prevalent mechanisms are the blockade of serotonin, noradrenaline and/or dopamine reuptake (e.g. SSRIs, SNRIs, NDRIs) or the inhibition of monoamine break-down in the synaptic cleft via MAO inhibition. This led to the formulation of the monoamine hypothesis of depression, which suggests that depression arises from a deficiency in monoamine neurotransmission in brain areas critical to the regulation of mood and other key symptoms of the disorder. This theory continues to prevail, even in the absence of clear evidence of monoamine deficits in the brain of depressed humans or animals exhibiting depression-like behavior (Stahl SM. Essential Psychopharmacology. 2nd ed.), and has led to validation of current animal models of depression primarily on the basis of monaminergic mechanisms. Consequently, it is questionable whether these models would be useful in identifying effective antidepressant drugs that work via other mechanisms. It is interesting to note that the current lack of non-monoaminergic antidepressants cannot be attributed to lack of effort directed at their discovery and development, and major efforts to test other mechanisms (e.g. substance P antagonists, CRF antagonists, gonadal steroids) have yet to provide clear proof of efficacy in humans, and other potentially therapeutic mechanisms may remain untapped due to limitations of our current screening methods. Read more....
Psychofysiologie.be
Inschrijving cursus psychofysiologie: Herfst 2007
Hurry.... numbers are limited.25 augustus 2007
I Screem
Screem rather then Scream !
Sometimes You just scream for a much needed song or sound. Is it legal ? We sure hope so but anyway it really is PFF: powerfull, fast and furious !
Computational Intelligence Society
If You can understand this blog You could entitle for membership
Stay tuned here for the anoouncement of the next ESANN meeting (Bruges, april 2008)
The incredibly shrinking brain
Can Disk cause your brain to shrink ?
22 augustus 2007
Blind sources see the light
Can You hear this blind whisper in the crowd ?
After reading this book You just might.
dedicated to a friend called Dieter.
Book Description
This is the first book to provide a cutting edge reference to the fascinating topic of blind source separation (BSS) for convolved speech mixtures. Through contributions by the foremost experts on the subject, the book provides an up-to-date account of research findings, explains the underlying theory, and discusses potential applications. The individual chapters are designed to be tutorial in nature with specific emphasis on an in-depth treatment of state of the art techniques.
Blind Speech Separation is divided into three parts:
Part 1 presents overdetermined or critically determined BSS. Here the main technology is independent component analysis (ICA). ICA is a statistical method for extracting mutually independent sources from their mixtures. This approach utilizes spatial diversity to discriminate between desired and undesired components, i.e., it reduces the undesired components by forming a spatial null towards them. It is, in fact, a blind adaptive beamformer realized by unsupervised adaptive filtering.
Part 2 addresses underdetermined BSS, where there are fewer microphones than source signals. Here, the sparseness of speech sources is very useful; we can utilize time-frequency diversity, where sources are active in different regions of the time-frequency plane.
Part 3 presents monaural BSS where there is only one microphone. Here, we can separate a mixture by using the harmonicity and temporal structure of the sources. We can build a probabilistic framework by assuming a source model, and separate a mixture by maximizing the a posteriori probability of the sources.
STISIM
Many recovering patients and aging drivers are at risk because psychomotor and cognitive impairment which affects their ability to drive safely. Simulation is ideal for safely and efficiently screening drivers, and for rehabilitating various post recovery conditions (e.g. stroke, traumatic head injury, etc.) Occupational therapists have used STISIM Drive™ for both assessment and rehabilitation and some papers have been published on these applications. Driving simulation can safely and efficiently assess and train impaired drivers under hazardous conditions that could never be controlled or tolerated in real world driving. Many video's here
20 augustus 2007
Neurosciences need Statistics
http://www.ivpv.ugent.be/
Neurosciences need good knowledge of Statistics
Learn it here by experts in the field (IVPV)
Vormende waarde De doelstelling van deze opleiding is een praktisch inzicht te geven in veelgebruikte en nuttige statistische methoden voor de bedrijfswereld. Een probleem bij het analyseren van data is de keuze die men dient te maken tussen het ruime aanbod aan statistische methoden. Deze keuze berust immers op een grondige kennis van de voorwaarden waaronder de statistische methode ontwikkeld is. Eens een verantwoorde methode geselecteerd is, kan de uitvoering van de analyse worden aangevat. Dit stadium is de jongste jaren sterk vereenvoudigd wegens de ruime verspreiding van statistische software pakketten (S-PLUS, SAS, SPSS, Statistica, ...). Tenslotte dienen de resultaten van de analyse geïnterpreteerd te worden. Ook hierbij is een grondige kennis van de kracht en de tekortkomingen van de gebruikte statistische techniek onontbeerlijk. In deze lessenreeks zal op deze drie fasen worden ingegaan en tijdens een aantal begeleide oefeningen zullen de cursisten zelf gegevens kunnen analyseren en interpreteren. Er zal ook nadruk worden gelegd op een fase waaraan maar al te vaak te weinig aandacht wordt geschonken: de opzet van een studie. Deze is meestal onontbeerlijk om tot een geldige statistische analyse en een verantwoord besluit te komen. De opleiding bestaat uit vier modules: een basiscursus statistiek,een cursus regressieanalyse, een cursus over niet-parametrische methoden en een cursus over multivariate methoden. In de basiscursus (module 1) worden de belangrijkste statistische begrippen uitgebreid herhaald en worden de klassieke methoden voor het vergelijken van gemiddelden besproken (t-testen en ANOVA). In module 2 wordt de regressie-analyse gedetailleerd besproken. Naast de analysemethoden, wordt in beide modules veel aandacht besteed aan de proefopzet. In de derde module over niet-parametrische methoden worden de niet-parametrische tegenhangers van de methoden uit modules 1 en 2 behandeld. Deze methoden worden gekenmerkt door hun algemene geldigheid, zonder dat distributionele veronderstellingen over de data gemaakt moeten worden. Module 4 handelt over de meest gebruikte multivariate statistische analysetechnieken, die dicht aanleunen bij datamining (clustering, classificatie, ...). Iedere module wordt afgesloten met een extra lesavond waarin alleen oefeningen gemaakt worden. De modules zijn zodanig opgebouwd dat cursisten zich voor elke module afzonderlijk (uitgezonderd voor module 0) of voor de volledige cursus kunnen inschrijven. | |
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Learn-it-all Cognitive Neuroscience
LEARN ALL THERE IS TO KNOW
(or maybe a bit less..)
The human brain is the most complex, sophisticated, and powerful information-processing device known. To study its complexities, the Department of Brain and Cognitive Sciences at the Massachusetts Institute of Technology combines the experimental technologies of neurobiology, neuroscience, and psychology, with the theoretical power that comes from the fields of computational neuroscience and cognitive science. The Department was founded by Hans-Lukas Teuber in 1964 as a Department of Psychology, with the then-radical vision that the study of brain and mind are inseparable. Today, at a time of increasing specialization and fragmentation, our goal remains to understand cognition- its processes, and its mechanisms at the level of molecules, neurons, networks of neurons, and cognitive modules. We are unique among neuroscience and cognitive science departments in our breadth, and in the scope of our ambition. We span a very large range of inquiry into the brain and mind, and our work bridges many different levels of analysis including molecular, cellular, systems, computational and cognitive approaches.
Since the field of brain and cognitive sciences is relatively young and extremely dynamic, there is no single text that encompasses the subject matter covered in most of the classes offered by the department. To educate and train future scientists, readings are from primary journal articles or research papers. This approach provides broad coverage, as well as the depth needed, so that students are exposed to cutting-edge knowledge in the various specialties of neuroscience and cognitive science. Browsing the course materials in MIT OpenCourseWare, the jewels are revealed in the detailed reading lists that provide a window on the current thinking in each subject.
Central to our mission is the training of graduate students in the brain and cognitive sciences, and the education of undergraduate students. Our graduate students benefit from the comprehensiveness of our program as well as by conducting research with individual faculty members who are on the cutting edge of their fields. The Department recently expanded its undergraduate program to include both neuroscience and cognitive science and our major is now one of the fastest growing in the institute.
For more information, go to http://web.mit.edu/bcs/
Brain gear
Gear up Your Brain
Source: SCIAM
An enzyme in the brain that behaves like a "continuous motor," constantly strengthening the connections between neurons, appears to be behind long-term memory storage.
The chemical, protein kinase Mζ (PKMζ), is part of a family of over 500 kinase enzymes, most of which transmit outside information into nerve cells.
"Most of these motors are in an inactive state, like an engine in a car that's parked," says Todd Sacktor, a professor of neurology at the State University of New York Downstate Medical Center in New York City. "You have to turn it on by pressing the accelerator; as soon as you take your foot off the accelerator, it stops." But unlike its other family members, PKMζ, which was discovered in 1993, is synthesized when a memory is formed and then "essentially has no controls" and functions continuously, as if it had no "off" switch.Sacktor, along with Reut Shema and Yadin Dudai, neurologists at the Weizmann Institute of Science in Rehovot, Israel, set out to determine what would happen if they blocked the enzyme at different intervals after a rat performed a learning task, in this case the recollection of eating an unappetizing meal. Their findings, published in this week's Science: they could erase those memories any time after a rat learned to avoid the unsavory snack by injecting a PKMζ inhibitor called ZIP into a midbrain region, the insular cortex (or insula)—home of the taste-processing gustatory cortex.
There are receptors for neurotransmitters (chemicals that transmit messages between brain cells) in the synapses (spaces) between neurons. PKMζ drives more receptors for the neurotransmitter glutamate, which is linked to learning and memory, to go into the synapse, thus strengthening their connection. "ZIP is a jam that stops the motor from enhancing synaptic strength," Sacktor says, "so, synapses go back to their normal strength and the memory is lost."
The researchers offered the rats water laced with the sugar substitute saccharin. They then gave their subjects an injection that induced nausea—causing the animals to develop a prominent aversion to saccharin-doped water. Afterward, regardless of when ZIP was administered, the rats forgot their saccharin-water intolerance within two hours of receiving the drug. Further, none of the rodents given ZIP (after developing an aversion to the sweetened water) recovered their memory over the course of the 25-day study. The rats could, however, relearn their distaste for the water if put through the drill again.
"I would say it's probably closer to the complete wiping," Sacktor says about the action of ZIP, indicating that it likely destroys all taste memory in the gustatory cortex. "We're erasing the contents of the hard disk … within two hours you could learn that association all over again and keep it."
Sacktor believes that this finding could one day be harnessed to help counteract the effects of post-traumatic stress disorder and to dampen the pain sensation. "Chronic pain is believed to be a strengthening of synapses in the pain pathways, so this could be a treatment for that," he says. "There is no treatment currently."18 augustus 2007
Mange your Signals
DSP: Tips and Tricks
From Richard Lyons DSP dragonmaster himself.
A noteworthy book for all DSP afficionado's.
A very different DSP book! Tips, tricks of the trade, practical shortcuts, and clever, real-world engineering solutions you didn't learn in school—from a "dream team" of experienced signal-processing professionals
The practicing engineer's need for guidance on how to make DSP work led editor Richard Lyons to create his popular "DSP Tips & Tricks" column in IEEE Signal Processing Magazine. Now, Streamlining Digital Signal Processing collects those articles—each originally written by a different practicing DSP engineer—that have undergone careful editorial review and incorporated feedback from the magazine's readers, and added more explanations, applications, and illustrations. These new, highly readable chapters cover an assortment of signal processing topics such as digital filtering, spectrum analysis, specialized signal generation, high-speed function approximation, and more. While rich in the specialized DSP tips and tricks that make it a valuable resource for experienced working engineers, this book also contains sufficient fundamental DSP theory and simple mathematics to make it accessible to students.
This is so much more than just another DSP textbook—it bridges the theory-to-practice gap and gives practicing engineers and computer programmers the useful, real-life tips, tricks, and techniques they need to make DSP hardware and software designs operate faster, with improved accuracy and increased computational efficiency.
Synapses in backgear
This is what I call "Reverse Engineering". Synapses backfire ! PSD-95 is the name of the game as a team lead by Kensuke Futai et al at Riken's Research found out. They wrote...
“Beta-amyloid accumulation, which is a major symptom of Alzheimer's disease, causes the loss of PSD-95 from synapse,” says Futai. “It’s perhaps not unexpected that Alzheimer's patients have less PSD-95 since Alzheimer’s patients cannot maintain memories, and because PSD-95 is important for synaptic function.” Yet, increasing the amount of PSD-95 in Alzheimer-diseased neurons to treat memory problems is not very realistic at present, he adds.
Other types of trans-synaptic molecules factors still await intensive study. “I would like to apply [the] same technology we used [in] the present study to other trans-synaptic and retrograde molecules. By doing further studies, I think we will understand better how synapses [memories] are maintained [stored] in the brain,” says Futai. “Regarding further work on PSD-95–neuroligin–β-neurexin, I would also like to know if a relationship exists between these protein-protein interactions and the development of autism.”
Brainclinic
BRAINCLINICS ?
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