Complexity Digest 2001.45

05-Nov-2001

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Content

  1. Tackling The Brain's Genetic Complexity, Nature Neuroscience
  2. Pyramidal Cell In Cognition: Comparative Study In Human & Monkey, J. Neuroscience
  3. Electrical Activity And Development Of Neural Circuits, Nature Neuroscience
    1. How Smell Develops, Nature Neuroscience
  4. Investigations of Locomotor Capacity as a Model System, Annu. Rev. Ecol. Syst.
  5. Perceptual Basis Of Bimanual Coordination, Nature
  6. Complex Systems As Fundamental Theory Of Sports Coaching?, arXiv
  7. Depression, Antidepressants, And The Shrinking Hippocampus, PNAS
    1. Stress-Induced Changes In Cerebral Metabolites Prevented By Antidepressant, PNAS
  8. On The Impossibility Of Predicting The Behavior Of Rational Agents, PNAS
  9. Multiscale Computing, PNAS
  10. Location Behaviour, Spatial Patterns, And Agent-Based Modeling, JASSS
  11. Bird Migration: Magnetic Cues Trigger Extensive Refueling, Nature
  12. Biographical Essay on W. Grey Walter, Latest Freeman Manuscripts
    1. Robot Dog 'Bugs' Inventor, Wired News
  13. Scientists Discover Gene That Helps Protect Cells From Destructive Form Of Oxygen, Assoc Press
  14. A Simple Computational Predictor Of Enzyme Function From Structure, PNAS
  15. Metabolic Rate And Environmental Productivity: Evolved To Run And Idle Fast, PNAS
  16. Modeling the Emergence of Possession Norms Using Memes, JASSS
  17. Pair Interactions: Real and Perceived Attitudes, JASSS
  18. Consensus and Cohesion in Simulated Social Networks, JASSS
  19. Complex Challenges: Global Terrorist Networks
    1. Six Degrees of Mohamed Atta, Business 2.0
    2. America's Secret Weapon, Business 2.0
    3. Search For Bombs, Not Nail Clippers, salon.com
    4. Five Thoughts: Cyberterrorism, Darwin Mag
    5. The War on Terrorism, the World Oil Market and the U.S. Economy, Brookings Preprint
  20. Links & Snippets
    1. Other Papers
    2. Conference Announcements

  1. Tackling The Brain's Genetic Complexity, Nature Neuroscience Next Article Bookmark and Share

    Excerpts: Neuroscientists will be able to (…) make a catalogue of the cell types that comprise the brain. This catalogue will be based on the genes expressed in each area, ideally following examination of individual cells. The catalogue will provide for several important advances. First, we will know how many different types of cells we are dealing with. Second, on the basis of gene expression patterns, strains of mice bearing green fluorescent protein or other live reporters can be created to mark specific cell types;

  2. Pyramidal Cell In Cognition: Comparative Study In Human & Monkey, J. Neuroscience Next Article Bookmark and Share

    Summary: One of the fundamental questions addressed by both theorists and experimentalists alike relates to cognition. More specifically, how do we think and how may that process be different to other species. Here we present tangible evidence which suggests that the circuitry of cognition is very different to that involved in sensory processing and even that involved in cross modal sensory-association. The basic building block of cortical circuitry, the pyramidal cell is considerably more complex in human prefrontal cortex than in other cortical regions involved in sensory processing. There is an overall gradient in the structural complexity of pyramidal cells through sensory, sensory-association and executive cortex.

    Here we present evidence that the extent of the regional differences in the pyramidal cell phenotype varies markedly in cortex of different anthropoid species. Regional, and species, differences in the complexity of pyramidal cells between humans and non-human primates can not be explained by brain size. Instead, the pyramidal cell phenotype appears to accord with the degree to which a cortical region has become specialized for a particular cortical function. These results suggest that highly complex pyramidal cells (and the circuits they form) are required to perform complex cortical functions such as comprehension, perception, and planning.


  3. Electrical Activity And Development Of Neural Circuits, Nature Neuroscience Next Article Bookmark and Share

    Abstract: A distinct feature of the nervous system is the intricate network of synaptic connections among neurons of diverse phenotypes. Although initial connections are formed largely through molecular mechanisms ( ), spontaneous and experience-driven electrical activities in the developing brain exert critical epigenetic influence on synaptic maturation and refinement of neural circuits.

    Excerpts: Electrical activity in the nervous system occurs in two general forms: spontaneous activity independent of sensory inputs or motor outputs, and experience-driven or use-dependent activity. For example, before an animal has any visual experience, spontaneous activity is found in various parts of the embryonic retina and thalamus.


    1. How Smell Develops, Nature Neuroscience Next Article Bookmark and Share

      Abstract: The mouse's sense of smell is built of 1000 input channels. Each of these consists of ( ) neurons that express the same odorant receptor gene and project their axons to the same targets (glomeruli) in the olfactory bulb.( ). The mechanisms of odorant receptor gene choice and axonal wiring are central to the functional organization of the mammalian olfactory system.

  4. Investigations of Locomotor Capacity as a Model System, Annu. Rev. Ecol. Syst. Next Article Bookmark and Share

    Abstract: Understanding adaptation in morphological and physiological traits requires elucidation of how traits relate to whole-organism performance and how performance relates to fitness. A common assumption is that performance capacities are utilized by and important to organisms. For some systems, it is assumed that high levels of physical fitness, as indexed by measures of locomotor performance, lead to high fitness levels. Although biologists have appreciated this, little attention has been paid to quantifying how organisms use their performance capacities in nature. We argue that for the study of adaptation to proceed, greater integration of laboratory studies of performance and behavioral/ecological studies is needed, and we illustrate this approach by examining two questions. First, how does the environment affect locomotor function in nature? Second, what percentage of locomotor capacities do animals use in nature? A review of studies in several animal groups shows widespread effects of the environment on measures of locomotor function.

  5. Perceptual Basis Of Bimanual Coordination, Nature Next Article Bookmark and Share

    Excerpts: Periodic bimanual movements are often the focus of studies of the basic organizational principles of human actions. In such movements there is a typical spontaneous tendency towards mirror symmetry. (…) Traditionally, this phenomenon has been interpreted as a tendency towards co-activation of homologous muscles, probably originating in motoric neuronal structures. Here we provide evidence contrary to this widespread assumption. We show for two prominent experimental models-bimanual finger oscillation1 and bimanual four-finger tapping-that the symmetry bias is actually towards spatial, perceptual symmetry, without regard to the muscles involved.

  6. Complex Systems As Fundamental Theory Of Sports Coaching?, arXiv Next Article Bookmark and Share

    Abstract: We argue that traditional Western science cannot adequately describe sports and other types of human behavior. Then we make an argument why a complex adaptive systems approach has the potential to provide the foundation for such a theory. We claim that a special role will be played by biological quantum computation in the human brain that should have emerged through biological evolution. Biological quantum computation could have provided evolutionary advantages in the area of decision-making and fast motor responses, when a number of potential actions -represented as a set of points in a high dimensional state-space- are available to the agent. While for animals and early humans these rapid, coordinated motor activities had direct survival value, today they are mostly manifested in competitive sports events. We suggest that entanglement can be facilitated by systematic sports coaching.

  7. Depression, Antidepressants, And The Shrinking Hippocampus, PNAS Next Article Bookmark and Share

    Excerpts: Throughout human history, it has been apparent that few medical maladies are as devastating in their effects as major depression. And since the 1950s, with the advent of the first generation of antidepressants, it has been apparent that depression is a biological disorder. (…)

    Both the tragic components and the intellectual challenge of depression have deepened in the last decade with a series of high-visibility reports that indicate prolonged, major depression is associated with atrophy within the central nervous system


    1. Stress-Induced Changes In Cerebral Metabolites Prevented By Antidepressant, PNAS Next Article Bookmark and Share

      Excerpt: Stress-induced structural remodeling in the adult hippocampus, involving debranching and shortening of dendrites and suppression of neurogenesis, provides a cellular basis for understanding the impairment of neural plasticity in the human hippocampus in depressive illness. Accordingly, reversal of structural remodeling may be a desirable goal for antidepressant therapy. The present study investigated the effect of tianeptine, a modified tricyclic antidepressant, in the chronic psychosocial stress model of adult male tree shrews (Tupaia belangeri), a model with high validity for research on the pathophysiology of major depression.

  8. On The Impossibility Of Predicting The Behavior Of Rational Agents, PNAS Next Article Bookmark and Share

    Excerpts: A foundational assumption in economics is that people are rational: they choose optimal plans of action given their predictions about future states of the world. (…) We demonstrate that there is an inherent tension between rationality and prediction when players are uncertain about their opponents' payoff functions. Specifically, there are games in which it is impossible for perfectly rational players to learn to predict the future behavior of their opponents (even approximately) no matter what learning rule they use.

  9. Multiscale Computing, PNAS Next Article Bookmark and Share

    Excerpts: Multiscale computing (MSC) involves the computation, manipulation, and analysis of information at different resolution levels. Widespread use of MSC algorithms and the discovery of important relationships between different approaches to implementation were catalyzed, in part, by the recent interest in wavelets. We present two examples that demonstrate how MSC can help scientists understand complex data. The first is from acoustical signal processing and the second is from computer graphics.

    (…) The field has undergone tremendous advances during the past decade because of the increase in inexpensive, powerful hardware.


  10. Location Behaviour, Spatial Patterns, And Agent-Based Modeling, JASSS Next Article Bookmark and Share

    Abstract: This paper presents an Agent-based LOcation Model (ABLOoM). ABLOoM simulates the location decisions of two main types of agents, namely households and firms. The model contains multiple interactions that are crucial in understanding land use changes, such as interactions of agents with other agents, of agents with their environment and of agents with emerged patterns. In order to understand the mechanisms that are at the basis of land use changes and the formation of land use patterns, ABLOoM allows us to study human behaviour at the microlevel in a spatial context. The models, which include economic theory, aspects of complexity theory and decision rules, show that it is possible to generate macrolevel land use patterns from microlevel spatial decision rules.

  11. Bird Migration: Magnetic Cues Trigger Extensive Refueling, Nature Next Article Bookmark and Share

    Excerpt: Long stretches of sea and desert often interrupt the migration routes of small songbirds, whose fat reserves must be restored before these can be crossed as they provide no opportunity for refuelling. To investigate whether magnetic cues might enable inexperienced migratory birds to recognize a region where they need to replenish their body fat, we caught and held thrush nightingales (Luscinia luscinia) in Sweden just before their first migration and exposed them to a magnetic field simulating that at a migratory stopover in northern Egypt, before the Sahara Desert.

  12. Biographical Essay on W. Grey Walter, Latest Freeman Manuscripts Next Article Bookmark and Share

    Contributing Editor's Note: The following is excerpts taken from Biographical essay on W. Grey Walter, prepared for the Nature Publishing Group. Grey Walter, an electronics engineer with earlier accomplishments in electroencephalography made a 'very simple brain' that endowed his artificial 'tortoise' with complex adaptive behaviors. It was constructed with two miniature valves serving as 'neurons', two mechanical relays, two capacitors,two receptors, and two motors. These complex and not fully predictable behaviors of exploration, discrimination, adaptation to changing internal and external environments, optimization, and stabilization of the internal medium were done with it.

    Excerpts: An autonomous robot embodies the principles of goal-seeking and scanning that characterize animal behavior. The concept of a machine that would define a goal and seek it by scanning resonated with his interest in brains ( ). He undertook to incorporate these two cognitive operations, goal-seeking and scanning, into an electronic 'toy' that would simulate these most basic characteristics of animal (and human) behavior.

    His devices were the forerunners of currently emerging machines that are governed by nonlinear dynamics, and that rely on controlled instability, noise, and chaos to achieve continually updated adaptation to ever changing and unpredictable worlds.


    1. Robot Dog 'Bugs' Inventor, Wired News Next Article Bookmark and Share

      Unlike Aibo, the B.I.O. bugs don't rely on a big computer brain to function. Although the bug-bots do use some simple computer chips, their design is actually based on robots that use only basic electronic circuitry to create "nervous networks" that can behave in very lifelike ways. In short, their genius lies in the body, and not the brain.

      Mark Tilden designed the toys based on his 10 years of work as a roboticist and physicist with the federal lab in Los Alamos, New Mexico.


  13. Scientists Discover Gene That Helps Protect Cells From Destructive Form Of Oxygen, Assoc Press Next Article Bookmark and Share

    Excerpt: (...) Researchers have discovered a gene that protects cells from a destructive form of oxygen and could possibly give mammals a longer life span. The discovery could lead to drugs to help cells resist aging.

    In laboratory studies at the National Institutes of Health, researchers studied mice that had been bred to lack a specific gene linked to neutralizing the effects of oxygen free radicals. The mice tended to have a life span about 40 percent shorter than mice with normal genes.

    The gene makes an enzyme called methionine sulfoxide reductase, or MsrA, which studies show helps to protect cells from being damaged by a type of highly reactive oxygen (...)


  14. A Simple Computational Predictor Of Enzyme Function From Structure, PNAS Next Article Bookmark and Share

    Excerpts: We show that theoretical microscopic titration curves (THEMATICS) can be used to identify active-site residues in proteins of known structure. Results are featured for three enzymes: triosephosphate isomerase (TIM), aldose reductase (AR), and phosphomannose isomerase (PMI). We note that TIM and AR have similar structures but catalyze different kinds of reactions, whereas TIM and PMI have different structures but catalyze similar reactions. (…) Additional results are given in summary form to show the success of the method for proteins with a variety of different chemistries and structures.

  15. Metabolic Rate And Environmental Productivity: Evolved To Run And Idle Fast, PNAS Next Article Bookmark and Share

    Excerpts: Even among vertebrate species of the same body mass and higher-level taxonomic group, metabolic rates exhibit substantial differences, (…) For metabolic rates of our five species, the driving environmental variable is environmental productivity itself (and hence food availability), rather than temporal variability of productivity. Thus, species that have evolved in the presence of abundant food run their metabolism "fast," both while active and while idling, as compared with species of less productive environments, even when all species are given access to unlimited food.

  16. Modeling the Emergence of Possession Norms Using Memes, JASSS Next Article Bookmark and Share

    Abstract: In this paper we study the emergence and the effects of a possession norm in an artificial society. We link the study of norms and the concept of memes as put forward by Richard Dawkins. Normative behaviour is modelled using memes as carriers for certain behaviours. For our simulations we extend the sugarscape model from Epstein and Axtell (1996) and give the agents the possibility to claim possession of a "plot" of land. Memes regulate the behaviour of the agents regarding the land claims of others. It turns out that the probability for the survival of the population is much higher when possession claims of others are respected. However, there exist short term disadvantages for agents respecting the possessions of others. Thus, the need for a possession norm arises. The introduction of sanctions provides a good possibility to enforce the norm as long as no costs arise for sanctioning agents. We also investigate different kinds of memepropagation and their effects on the establishment of the norm.

    Contributing Editor's Note: With the results of this work we could argue that we developed norms (and laws) because we can live better with them, and societies without them are extinguished. Social norms limit the behavior of individuals, but it seems that if they are too limiting the survival rate would decrease also. Social norms seem to emerge for limiting only the behaviors that prejudice other individuals. There is no need for further limiting.


  17. Pair Interactions: Real and Perceived Attitudes, JASSS Next Article Bookmark and Share

    Abstract: In this article we look at how a social interaction model can be developed that takes into account the influence that perceived attitudes can have on the resulting dynamics. The model is based on a pair interaction situation and a master equation approach. The model can be easily programmed using standard high level simulation languages. Some simulation studies are presented in the article.

  18. Consensus and Cohesion in Simulated Social Networks, JASSS Next Article Bookmark and Share

    Abstract: Social structure emerges from the interaction and information exchange between individuals in a population. The emergence of groups in animal and human social systems suggests that such social structures are the result of a cooperative and cohesive society. Using graph based models, where nodes represent individuals in a population and edges represent communication pathways, we simulate individual influence and the communication of ideas in a population. Simulations of Dunbar's hypothesis (that natural group size in apes and humans arises from the transition from grooming behaviour to language or gossip indicate that transmission rate and neighbourhood size accompany critical transitions of the order proposed in Dunbar's work. We demonstrate that critical levels of connectivity are required to achieve consensus in models that simulate individual influence.

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

    Earlier in this column, Valdis Krebs introduced his suggestion to study graphical representations of the terrorists' personal network. (see ComDig01-40/#19). This approach is now featured in a report on this issue in Business 2.0 : "(…) Valdis Krebs's examination of the interrelationships between the 19 hijackers aboard the planes used in the Sept. 11 attack and 15 people authorities say are connected with them. Employing proprietary software called InFlow, normally used to help companies improve communication, Krebs entered every publicly disclosed contact between people in the network. He then dated and weighted the contacts. Strong ties -- such as sharing a house or attending the same flight school -- got more weight than weak ones such as telephone calls."

    1. Six Degrees of Mohamed Atta, Business 2.0 Next Article Bookmark and Share


    2. America's Secret Weapon, Business 2.0 Next Article Bookmark and Share

      In the same issue the concept of "Netwar" is discussed:

      "The United States is at war with a foe that is, as the cliche has it, "a shadowy terrorist network," a multinational private army whose nodes and lines of communication reach invisibly and murderously across national borders. It's centipedal, multiheaded, hard to find, difficult to kill. Don't be fooled by familiar-seeming before-and-after images of bomb damage or shots of jet fighters streaking off the decks of aircraft carriers: This is a new kind of war -- netwar. "Netwar requires a whole new set of strategies and tactics," (…)"

      The same magazine holds two public panel discussions on America's Secret Weapon.


    3. Search For Bombs, Not Nail Clippers, salon.com Next Article Bookmark and Share

      Airport security depends to a large degree on the human security agents who search the passenger's luggage for weapons and bombs. From complex systems we know that the instructions that the agents receive are crucial for the success of the operation and the level of security that can be achieved. On a recent international flight with domestic connecting flights we could observe that these procedures seem to be less than optimal and not consistent with each other. For instance in Detroit airport on 01//11/07 passengers could not even get a plastic knife in the airport restaurants for their meals. Once they boarded the plane, they got their meals served, including plastic knives. On 01/11/01 at the same airport, security agents confiscated my key-ring carabiner because it could potentially be used to strike someone. When I asked the security agents, if they could identify plastic explosives, if there were any in my carry-on luggage, they had to decline, they didn't know what it would look like.

      Maybe I was lucky that my uttering the words "plastic explosives" did not trigger the evacuation of the terminal building, something that apparently happened when a pilot used the word "gun" at a Baltimore airport when he protested the confiscation of is nail clipper. Extreme literal interpretation of rules can in the end lead to less and not more security when people stop taking them serious.

      Search For Bombs, Not Nail Clippers, P. Smith, salon.com, 01/10/30

    4. Five Thoughts: Cyberterrorism, Darwin Mag Next Article Bookmark and Share

      See also: Five Thoughts: Cyberterrorism, Stephen T. Barish, manager of security technology solutions at Ernst & Young and former operations planner for the Department of Defense, offers advice on how to guard against cyberterrorism.

    5. The War on Terrorism, the World Oil Market and the U.S. Economy, Brookings Preprint Next Article Bookmark and Share

      "The War on Terrorism, the World Oil Market and the U.S. Economy," Analysis Paper #7, by George Perry; Brookings Project on Terrorism, and American Foreign Policy (Oct. 2001)

  20. Links & Snippets Next Article Bookmark and Share

    1. Other Papers Next Article Bookmark and Share

      1. Telomere Dysfunction Triggers Extensive DNA Fragmentation And Evolution Of Complex Chromosome Abnormalities In Human Malignant Tumors, David Gisselsson, Tord Jonson, Asa Petersen, Bodil Strombeck, Paola Dal Cin, Mattias Hoglund, Felix Mitelman, Fredrik Mertens, Nils Mandahl, PNAS 2001;98 12683-12688
      2. Do Irregular Grids make a Difference? Relaxing the Spatial Regularity Assumption in Cellular Models of Social Dynamics, Andreas Flache and Rainer Hegselmann. JASSS, Vol 4 Issue 4. 31-Oct-2001.
      3. Auditory Representation Of The Vocal Repertoire In A Songbird With Multiple Song Types, Richard Mooney, William Hoese, and Stephen Nowicki, PNAS 2001;98 12778-12783
      4. Chaos And Stability Of The Solar System, Renu Malhotra, Matthew Holman, and Takashi Ito, PNAS 2001;98 12342-12343
      5. Chaos in Black holes Surrounded by Electromagnetic Fields, Manuele Santoprete and Giampaolo Cicogna, arXiv. Paper ID: nlin.CD/0110046. 01/10/25
      6. Bats On The Rise, Jennifer Viegas, Discovery News, 01/10/31
      7. Telling Tails, Mary B. Kennedy, Pat Manzerra, PNAS 2001;98 12323-12324
      8. What Visual Perception Tells Us About Mind And Brain, Shinsuke Shimojo, Michael Paradiso, Ichiro Fujita. PNAS 2001;98 12340-12341
      9. Hunting In Packs, John Cornwell, The Sunday Times, 01/10/28, Book report on : Emergence The Connected Lives of Ants, Brains, Cities and Software, Steven Johnson, Allen Lane, 01/10/24, See also Complexity Digest 2001.37.2

    2. Conference Announcements Bookmark and Share

      1. International Conference on Systems Thinking Globally Concerned, Vienna, Austria, 01/11/01-04
      2. 2nd International Conference on Systems Biology: The Future of Biology in the 21st Century, Pasadena, CA, 01/11/04-07
      3. Developing A Cyber-Democracy: "Government of the Future", Brookings Inst., Washington, DC. , 01/11/05-09
      4. Digitizing Decisions and Markets, Decision Sciences Institute Annual Meeting, San Francisco, 01/11/17-20
      5. America's Secret Weapon, Business 2.0 Live! Event, Stanford, 01/11/28
      6. II World Congress of Citizens Networks, Buenos Aires, Argentina, 01/12/05-07
      7. "Horizons In Complex Systems" in honor of H. Eugene Stanley's 60th birthday, Univ. Messina, Sicily, 01/12/05-08
      8. America's Secret Weapon, Business 2.0 Live! Event, Stanford, 01/12/07
      9. From Worker to Colony: Understanding the Organisation of Insect Societies, Isaac Newton Institute, Cambridge, UK. , 01/12/07-08
      10. Intl Conf on Current Trends In Differential Equations And Dynamical Systems, Kanpur, India, 01/12/15-17
      11. Complex Systems, Modeling Nonlinear Natural and Human Systems, Hawaii International Conference On System Sciences, HICSS-35, Hawaii, 02/01/07-10
      12. 1st Biennial Seminar on Philosophical, Methodological & Epistemological Implications of Complexity Theory, La Habana, Cuba, 02/01/07-11
      13. Topics in Nonlinear Dynamics, Collective Phenomena and Complexity: Dynamical Model Formulation, Analysis and Symmetry, Canberra, Australia, 02/01/21-02/01
      14. AIS'2002: Towards Component-Based Modeling and Simulation, Lisbon, Portugal, 02/04/07-10
      15. World Conference NL 2002 - Networked Learning in a Global Environment: Challenges and Solutions for Virtual Education, Berlin, Germany, 02/05/01-04
      16. International Conference on Complex Systems (ICCS2002), Nashua, NH, 02/06/9-14
      17. 7th International Conference on Music Perception & Cognition - ICMPC7, Sydney, 02/07/17-21
      18. Self-Organisation and Evolution of Social Behaviour, Monte Verità, Switzerland, 02/09/08-13

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