Complexity Digest 2002.07

18-Feb-2002

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Content

  1. Part Man, Part Computer: Researcher Tests the Limits, Science
    1. Will Retinal Implants Restore Vision?, Science
  2. The Bionic Man: Restoring Mobility, Science
    1. Inhibitory Control of Acquired Motor Programmes in the Human Brain, Brain
    2. Early Consolidation In Human Primary Motor Cortex, Nature
    3. Movement Control of Manipulative Tasks in Patients with Gilles de la Tourette Syndrome, Brain
  3. Brains Out Of Tune, Nature
    1. Sending Sound to the Brain, Science
  4. Watching The Brain Work: Looking At The Network Connections, Amer. J. Neuroradiology
  5. Speech Sounds Learned By Sleeping Newborns, Nature
    1. Late Plasticity for Language in a Child's Non-dominant Hemisphere: A pre- and post-Surgery fMRI Study, Brain
  6. Gut Thoughts, HMS Beagle
  7. Games to Take on a Life of Their Own Taylor: Copying the Brain's Neural Networks, BBC News Online's
  8. DNA-Based Computer Takes Aim at Genes, Science
  9. Genome Shuffling Leads To Rapid Phenotypic Improvement In Bacteria, Nature
  10. Leukemia Protein Spurs Gene Silencing, Science
    1. The Control of Phenotype: Connecting Enzyme Variation to Physiology
  11. Tracking Target And Spiral Waves, Chaos
  12. Goofy Galaxy Spins In Wrong Direction, CNN
  13. From Topology To Dynamics In Biochemical Networks, Chaos
  14. Robust Chaos: Implications For Brain Dynamics, Chaos
  15. Bush To Unveil Alternative Global Warming Plan, CNN
  16. Method To Directly Compare Levels Of Agricultural And Industrial Runoff Between Estuaries, Cornell Press Release
  17. Farmers in Peru Are Turning Again to Coca Crop, NYTimes
  18. Managing Emergent Phenomena: Nonlinear Dynamics In Work Organizations, New Book
  19. Complex Challenges: Global Terrorist Networks
    1. U.S. Tries To Identify Target Of Airstrike, CNN
  20. Links & Snippets
    1. Other Papers
    2. Conference Announcements

  1. Part Man, Part Computer: Researcher Tests the Limits, Science Next Article Bookmark and Share

    Excerpt: (...) will have surgery to connect nerves in his arm with wires leading to a "smart card"-sized collection of microprocessors. The wires will pick up signals from his central nervous system and relay them via a radio transmitter to an external computer that will record the patterns. Warwick hopes the device will pick up discrete signals from the nerves depending on his movements, his sense of touch, and even his mood, and then send those signals back to his nerves to see if they can mimic the movement or the sensation.

    1. Will Retinal Implants Restore Vision?, Science Next Article Bookmark and Share

      Excerpts: A number of research groups are developing electrical implants that can be attached directly to the retina in an attempt to restore vision (...). However, (...), there are still several major obstacles to overcome before retinal prostheses can be used clinically.

      Vision is an enormously complex form of information processing that depends on a remarkable neuroprocessor at the back of the eye called the retina. Seeing is initiated when light passing through the pupil of the eye is focused by the lens onto the retina's sensory neuroepithelium.


  2. The Bionic Man: Restoring Mobility, Science Next Article Bookmark and Share

    Excerpts: Bionics engineers are making increasingly bold and successful use of their tools to restore mobility to persons with missing or nonfunctional limbs. These tools include the latest materials, minielectronics and megacomputers, advanced robotic mechanisms, and algorithms. (...) the residual sensorimotor system can be tapped in order to transmit its intents to replacement or reactivated body parts. (...)

    Bionics can restore lost mobility to individuals if (i) they can express cognitive control over relevant motor functions somewhere in their residual anatomy and (ii) a device can pick up and decipher that cognition.


    1. Inhibitory Control of Acquired Motor Programmes in the Human Brain, Brain Next Article Bookmark and Share

      Excerpt: An important basis of skilled human behaviour is the appropriate retrieval of acquired and memorized motor programmes ('motor memory traces'). Appropriate retrieval is warranted if motor programmes are only activated if necessary and are, probably more often, inhibited if required by the context of a given situation. It is unknown how this type of inhibition is accomplished in the brain. (...) This concept is supported by the preliminary observations in dystonic patients who are known to have deficits of inhibitory motor control and in whom these context-dependent focal increases of oscillatory activity were absent.

      Editor's Note: The paradigm used in this article is that of "motor programs". It would be an interesting challenge to interpret these experimental results within the framework of complex systems.

       


    2. Early Consolidation In Human Primary Motor Cortex, Nature Next Article Bookmark and Share

      Excerpts: Behavioural studies indicate that a newly acquired motor skill is rapidly consolidated from an initially unstable state to a more stable state, whereas neuroimaging studies demonstrate that the brain engages new regions for performance of the task as a result of this consolidation. However, it is not known where a new skill is retained and processed before it is firmly consolidated. (...) Here we show that low-frequency, repetitive transcranial magnetic stimulation of M1 but not other brain areas specifically disrupted the retention of the behavioural improvement (...).

      • Early Consolidation In Human Primary Motor Cortex, Wolf Muellbacher, Ulf Ziemann, Joerg Wissel, Nguyet Dang, Markus Kofler, Stefano Facchini, Babak Boroojerdi, Werner Poewe, Mark Hallett, DOI: 10.1038/nature712, Nature AOP, Published online: 23 January 2002

    3. Movement Control of Manipulative Tasks in Patients with Gilles de la Tourette Syndrome, Brain Next Article Bookmark and Share

      Excerpt: When a hand-held object is moved, grip and load force are accurately coordinated for establishing grasp stability. In the present work, the question was raised whether patients with Gilles de la Tourette syndrome (TS), who show tic-like movements, are impaired in grip-load force control when executing a manipulative task. (...) Based on these data, we conclude that the ongoing activation of secondary motor areas may be explained by the TS patients' involuntary urges to move. Accordingly, interference will prevent an accurate planning of voluntary behaviour. Together, these findings reveal modulations in movement organization in patients with TS and exemplify degrading consequences for manual function.

  3. Brains Out Of Tune, Nature Next Article Bookmark and Share

     Excerpt: When their unmusical subjects were given a standardized battery of tests assessing these different dimensions, Peretz and co-workers found that there was a general failure in those tests involving pitch perception, whereas results in rhythm and metre tasks were more varied. In addition, the unmusical subjects were also insensitive to distortions of familiar tunes, and indifferent to dissonant chords. But they had no problem in recognizing familiar voices, environmental sounds and song lyrics. So a pitch-processing deficit was at the heart of the subjects' problems.

    1. Sending Sound to the Brain, Science Next Article Bookmark and Share

      Excerpt:  The cochlear implant, a microelectrode array that directly stimulates the auditory nerve, has greatly benefited many individuals with profound deafness. Deaf patients without an intact auditory nerve may be helped by the next generation of auditory prostheses: surface or penetrating auditory brainstem implants that bypass the auditory nerve and directly stimulate auditory processing centers in the brainstem.

  4. Watching The Brain Work: Looking At The Network Connections, Amer. J. Neuroradiology Next Article Bookmark and Share

    Contributing Editor's Note: The following paper stresses on the proper understanding of white and gray matter structures in the brain. The gray matter landmarks are readily identifiable and discrete motor and sensory functions associated with the gray matter anatomy are assessable to clinical observation, while white matter tracts are more opaque to clinical evaluation. So, the authors caution that analysis based on clinical abservation only may lead to oversimplified conclusions.

    Excerpts: It is also easy to oversimplify brain activity by only considering structures that encode sensory information and command movements because of the misperception of white matter fibers as mere conduits for the appropriate gray matter (...). This absurd scheme can reduce most brain functions to one large reflex arc. Motor and sensory regions, however, account for only a fraction (approximately 20%) of the cerebral cortex.

    It can be argued that cognitive abilities represent the most complex, important, and intriguing cerebral functions. In other words, these are the very psychological and neurologic processes that help to define our selves and our lives.


  5. Speech Sounds Learned By Sleeping Newborns, Nature Next Article Bookmark and Share

    Excerpts: It is not yet clear whether humans are able to learn while they are sleeping. Here we show that full-term human newborns can be taught to discriminate between similar vowel sounds when they are fast asleep. It is possible that such sleep training soon after birth could find application in clinical or educational situations. (...)

    We have shown that newborns can assimilate auditory information while they are sleeping, suggesting that this route to learning may be more efficient in neonates than it is generally thought to be in adults. 


    1. Late Plasticity for Language in a Child's Non-dominant Hemisphere: A pre- and post-Surgery fMRI Study, Brain Next Article Bookmark and Share

      Excerpts: The ability of the right hemisphere to sustain the acquisition or the recovery of language after extensive damage to the left hemisphere has been essentially related to the age at the time of injury. Better language abilities are acquired when the insult occurs in early childhood (perinatal insults) compared with later occurrence. However, while previous studies have described the neuropsychological pattern of language development in typical cases, the neural bases of such plasticity remain unexplored. (...) This first serial fMRI study illustrates the great plasticity of the child's brain and the ability of the right hemisphere to take over some expressive language functions, even at a relatively late age.

  6. Gut Thoughts, HMS Beagle Next Article Bookmark and Share

    Contributing Editor's Note: The gut is, in fact, a major immune organ, containing more immune cells than the rest of the body combined Deep in the gut lies a complex self-contained nervous system containing more nerve cells than the spinal cord even. There are over 100 million nerve cells in the human small intestine alone. So  the gut is referred to as 'second brain' as the former possesses a nervous system like the later. Interaction with it can affect, according to the author of the following work, mood and behavior by signaling the central nervous system.

    Abstract: Though few know about it, humans have a second brain that handles most of the body's digestive functions. Study (...) offering insight into malfunctions of the "gut brain" as well as the more complex cranial brain.

    Excerpts: What the gut has to do is extremely complicated, (...). If the brain had to control that, it would have to run huge cables and have a huge number of cells devoted solely to that purpose. It makes great evolutionary sense to separate these functions and essentially use a microcomputer that is independent rather than a central processing unit.


  7. Games to Take on a Life of Their Own Taylor: Copying the Brain's Neural Networks, BBC News Online's Next Article Bookmark and Share

    Excerpts: Video games of the future could have characters with almost human intelligence (...)

    Scientists from King's College in London are working on enabling computers to understand, speak, learn and eventually, think.

    They have created a technology called the Language Acquisition Device (LAD) which emulates the functions of the brain's frontal lobes where humans process language and emotion. (...)

    The system works by using neural networks to mimic brain function.

    It then learns language as children do, not through rules and vocabularies, but through association and example.


  8. DNA-Based Computer Takes Aim at Genes, Science Next Article Bookmark and Share

    Excerpt: First, he uses an algorithm that solves the problem in steps, building more and more complex DNA "formulas" as it goes and chemically weeding out failed solutions at the end of each round. That approach cuts the number of dead-end molecules by orders of magnitude, but at the cost of more chemistry. So Suyama automated the process, adding an electronic computer to control sample handling and processing. As a "killer application" for his machine, Suyama chose gene-expression profiling, a procedure increasingly used in research and drug development (...)

  9. Genome Shuffling Leads To Rapid Phenotypic Improvement In Bacteria, Nature Next Article Bookmark and Share

    Excerpts: For millennia, selective breeding, on the basis of biparental mating, has led to the successful improvement of plants and animals to meet societal needs1. At a molecular level, DNA shuffling mimics, yet accelerates, evolutionary processes, and allows the breeding and improvement of individual genes and subgenomic DNA fragments. (...). We demonstrate the use of this approach through the rapid improvement of tylosin production from Streptomyces fradiae. This approach has the potential to facilitate cell and metabolic engineering and provide a non-recombinant alternative to the rapid production of improved organisms.

  10. Leukemia Protein Spurs Gene Silencing, Science Next Article Bookmark and Share

    Excerpt:  Researchers have identified hundreds of genes that can, when mutated, cause uncontrolled cellular growth and other changes that underlie cancer. But in the past few years, increasing evidence has suggested that mutations aren't the only genetic changes that lead to cancer. The addition of certain chemical groups to genes or their associated proteins can also alter gene activity patterns in ways that result in malignancy, without disrupting gene structures. Exactly how cancer-related genes acquire these so-called "epigenetic" alterations hasn't been clear, however.

    1. The Control of Phenotype: Connecting Enzyme Variation to Physiology Next Article Bookmark and Share

      Abstract: Metabolic control analysis (...) was developed for the understanding of multi-enzyme networks. At the core of this approach is the flux summation theorem. This theorem implies that there is an invariant relationship between the control coefficients of enzymes in a pathway. One of the main conclusions that has been derived from the summation theorem is that phenotypic robustness to mutation (e.g. dominance) is an inherent property of metabolic systems and hence does not require an evolutionary explanation (...). Here we show that for mutations involving discrete changes (of any magnitude) in enzyme concentration the flux summation theorem does not hold. The scenarios we examine are two-enzyme pathways with a diffusion barrier, two enzyme pathways that allow for enzyme saturation and two enzyme pathways that have both saturable enzymes and a diffusion barrier. Our results are extendable to sequential pathways with any number of enzymes. The fact that the flux summation theorem cannot hold in sequential pathways casts serious doubts on the claim that robustness with respect to mutations is an inherent property of metabolic systems.

  11. Tracking Target And Spiral Waves, Chaos Next Article Bookmark and Share

    Abstract: A new algorithm for analyzing the evolution of patterns of spiral and target waves in large aspect ratio chemical systems is introduced. The algorithm does not depend on finding the spiral tip but locates the center of the pattern by a new concept, called the spiral focus (...). Moving target and spiral foci are found, and the speed and direction of movement of single as well as double spiral foci are investigated. For the experiments analyzed in this paper it is found that the movement of a focus correlates with foci in the immediate neighborhood independently of how they were created.

  12. Goofy Galaxy Spins In Wrong Direction, CNN Next Article Bookmark and Share

    Excerpts: Most spiral galaxies have arms of gas and stars that trail behind as they turn. But this galaxy, known as NGC 4266, has two leading outer arms that point toward the direction of the galaxy's rotation, according to Hubble researchers.

    "NGC 4622 suggests that maybe people do not know all that there is know about spiral structure yet. Our study may lead to a new understanding of spiral arm production in galaxies," (...)

    It could have hit and ingested a much smaller galaxy (...)


  13. From Topology To Dynamics In Biochemical Networks, Chaos Next Article Bookmark and Share

    Abstract: Abstract formulations of the regulation of gene expression as random Boolean switching networks have been studied extensively over the past three decades. These models have been developed to make statistical predictions of the types of dynamics observed in biological networks (...). For values of mean connectivity chosen to correspond to real biological networks, these models predict disordered dynamics. However, chaotic dynamics seems to be absent from the functioning of a normal cell. While these models use a fixed number of inputs for each element in the network, recent experimental evidence suggests that several biological networks have distributions in connectivity.

  14. Robust Chaos: Implications For Brain Dynamics, Chaos Next Article Bookmark and Share

    Abstract: Various techniques designed to extract nonlinear characteristics from experimental time series have provided no clear evidence as to whether the electroencephalogram (EEG) is chaotic. Compounding the lack of firm experimental evidence is the paucity of physiologically plausible theories of EEG that are capable of supporting nonlinear and chaotic dynamics. Here we provide evidence for the existence of chaotic dynamics in a neurophysiologically plausible continuum theory of electrocortical activity and show that the set of parameter values supporting chaos within parameter space has positive measure and exhibits fat fractal scaling.

  15. Bush To Unveil Alternative Global Warming Plan, CNN Next Article Bookmark and Share

    Excerpts: The Kyoto agreement (...) required mandatory reductions, whereas the Bush plan would be voluntary.

    However, administration officials told CNN that if the United States can get the global community, including developing nations, to participate in the president's plan, then the actual reduction of greenhouse emissions would be larger than under Kyoto.

    Bush rejected the Kyoto agreement, which 178 other nations accepted last year, because it exempted developing nations and large polluters such as India. (...)

    The president faced tremendous criticism from environmental groups and U.S. allies, including Japan, for rejecting Kyoto.


  16. Method To Directly Compare Levels Of Agricultural And Industrial Runoff Between Estuaries, Cornell Press Release Next Article Bookmark and Share

    Excerpt: (...) Although many of the world's major estuaries are polluted, until now there has not been a study that uniformly compares levels of nitrogen, carbon and phosphorus in two separate bodies of water. (...)

    "There have been many studies around the globe of the world's estuaries and coastal water systems. But to date there has not been a uniform approach to measure the effects of loads of nitrogen and phosphorus in those waters," says Dennis Swaney, an environmental biologist at the Boyce Thompson Institute (BTI) for Plant Research Inc., located on the campus of Cornell University in Ithaca, N.Y. (...)

    The researchers' approach is based on the conservation of mass. While water volume and salt content in the estuaries and coastal water areas remain approximately constant over time, nutrients such as nitrogen and phosphorus are taken up, or released, by biological processes in estuaries. As water flows through the system and mixes with adjacent systems, such as oceans or seas, the flows of water are described by scientists in terms of "water budgets" and the nutrients carried by these flows are described by "nutrient budgets." By examining discrepancies in nutrient budgets, scientists make inferences about biological productivity and other processes in estuaries around the globe. (...)


  17. Farmers in Peru Are Turning Again to Coca Crop, NYTimes Next Article Bookmark and Share

    Excerpts: While the reasons for the increase in Peru are complex, most experts attribute it largely to what they call the "balloon effect," in which eradication in one place simply pushes coca growing to another, given the continuing demand for cocaine, principally in the United States.

    Once-successful eradication efforts in Peru had already shifted much production to Colombia, where a $1.3 billion American-financed antidrug effort, called Plan Colombia, has now helped nudge coca growing back here again.

    [For the farmers in Peru, Ed.] (...) planting more coca simply makes economic sense (...)


  18. Managing Emergent Phenomena: Nonlinear Dynamics In Work Organizations, New Book Next Article Bookmark and Share

    Summary: The science and management of work organizations has been transformed by concepts from nonlinear dynamical systems theory, especially where self-organization processes are involved. MEP integrates nonlinear theory and empirical studies on work motivation and personnel selection, creative problem solving, organizational change, formation of networks, group coordination, leadership emergence, behavior in hierarchies, the management and forecasting of dynamical systems, and emergency management. MEP contains chapters on basic dynamics and empirical analysis with nonlinear regression.

  19. Complex Challenges: Global Terrorist Networks Next Article Bookmark and Share

    Editor's Note: To our knowledge this is one of the first examples of a military attack that was executed exclusively by remote control. Since apparently the operator of the drone has only video images available to identify the target, (probably in combination with local intelligence) the risk of deception ("call in a strike against your rival by naming him a terrorist") or selecting the wrong target (apparently individuals dressed in white (like the Taliban) with one of them being tall "like bin Laden" was the essential criterion to identify the target.

    1. U.S. Tries To Identify Target Of Airstrike, CNN Next Article Bookmark and Share

      Excerpt: A military investigative team has found "forensic evidence" that could determine whether a recent U.S. airstrike in Afghanistan killed top al Qaeda officials, the U.S. Central Command said Sunday. (...)

      The CIA has been flying Predator drones equipped with precision-guided missiles on reconnaissance missions in Afghanistan. The unmanned aerial vehicles are prepared to attack targets if instructed.


  • Links & Snippets Next Article Bookmark and Share

    1. Other Papers Next Article Bookmark and Share

      1. Attention to Action in Parkinson's Disease: Impaired Effective Connectivity among Frontal Cortical Regions, James Rowe, Klaas Enno Stephan, Karl Friston, Richard Frackowiak, Andrew Lees, and Richard Passingham, Brain, 2002 February 1; 125(2): p. 276-289
      2. Mysterious 'Alien' Corn Invades Mexico Countryside, Pav Jordan, Reuters, 1/29/02
      3. Sex Differences In Emigration And Mortality Affect Optimal Management Of Deer Populations, T. H. Clutton-Brock, T. N. Coulson, E. J. Milner-Gulland, D. Thomson, H. M. Armstrong, DOI: 10.1038/415633a, Nature 415, 633 - 637 (2002)
      4. Slowdown Of The Meridional Overturning Circulation In The Upper Pacific Ocean, Michael J. Mcphaden , Dongxiao Zhang, Nature 415, 603 - 608 (2002)
      5. Web Search, Darwin Mag, 02/02/13, There's so much out there. How do I know where to start?
      6. Internet Mosaic Continues To Grow, BBC, 02/02/12 All ages, cultures and religions are embracing the net
      7. Saving Skin, Alan Joch, Technology Review, 02/02/11, Tissue models of human skin offer an alternative to animal testing.
      8. Neuropsychology of Musical Perception: New Perspectives,Herve Platel, Brain, 2002 February 1; 125(2): p. 223-224

          


    2. Conference Announcements Bookmark and Share

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      1. Technology, Entertainment and Design (TED 12), Monterey, CA, 02/02/20-23
      2. ASPS [American Studies Project at Skeria] Seminar, Globalization and Business Cultures, Skellefteċ, Sweden, 02/02/15-
      3. Physik Sozio-Oekonomischer Systeme, Regensburg, Germany, 02/03/11-15
      4. Capturing Business Complexity with Agent-Based Modeling and Simulation, Argonne National Laboratory, Il. 02/03/04-08
      5. SwarmFest 2002: Sixth Annual Swarm Users Meeting, Seattle, 02/03/29-31
      6. AIS'2002: Towards Component-Based Modeling and Simulation, Lisbon, Portugal, 02/04/07-10
      7. Modeling & Simulation of Microsystems (MSM 2002) & Intl. Conf on Comp Nano Science (ICCN 2002), San Juan, Puerto Rico, 02/04/22-25
      8. World Conference NL 2002 - Networked Learning in a Global Environment: Challenges and Solutions for Virtual Education, Berlin, Germany, 02/05/01-04
      9. International Conference on Complex Systems (ICCS2002), Nashua, NH, 02/06/9-14
      10. Sitges Conference "Statistical Mechanics of Complex Networks", Sitges, Barcelona, SPAIN, 10-14 June 2002
      11. International Conference SocioPhysics, ZIF - Bielefeld, Germany, 02/06/06-09
      12. 2nd International Conference on Development and Learning (ICDL'02), MIT, Cambridge, Massachusetts USA, 02/06/12-15
      13. Let's Face Chaos Through Nonlinear Dynamics, Summer School/Conference, Maribor, Slovenia, 02/06/30 - 07/14
      14. 7th International Conference on Music Perception & Cognition - ICMPC7, Sydney, 02/07/17-21
      15. Self-Organisation and Evolution of Social Behaviour, Monte Verità, Switzerland, 02/09/08-13
      16. Complex Systems (CS02) Complexity with Agent-Based Modeling, Chuo University, Tokyo, Japan, 02/09/10-12
      17. 3rd Intl NAISO Symposium on Engineering Of Intelligent Systems (EIS 20020), Malaga, Spain, 02/09/24-27
      18. ACRI 2002, 5th Intl Conf on Cellular Automata for Research and Industry, Geneva, Switzerland, 02/10/09-11 
      19. Artificial Life VIII, UNSW, Sydney, Australia, 02/12/09-13

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