THYMOS
A newsletter of research on Consciousness, Mind and Life

by piero scaruffi

Researchers are welcome to submit news and articles about breakthroughs and events in the areas of cognitive science, artificial intelligence, neurobiology, artificial life, linguistics, neural networks, connectionism, cognitive psychology, mind, philosophy, psychology, consciousness. Email the editor at this Email address. Readers who would like to receive periodic news and updates on cognitive science, philosophy of mind, neurobiology, artificial intelligence, etc, are invited to register to my mailing list.

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December 2003
  • The invention of art had already been dated at about 30,000 years ago after the discovery of the statue of a woman in Willendorf, Austria. Now Nicholas Conard of the University of Tuebingen (Germany) has discovered a set of 2cm-tall figurines (a horse head, a water bird and a cat-like animal) in a cave in southwestern Germany. Besides shedding light on the development of artistic skills, this discovery also seems to confirm the theory that Europe was settled by people who migrated along the river Danube. The sophistication of the figurines shows that those immigrants were skilled in tool making and using. The rise of art is important for the study of cognition because it implies the ability to communicate by symbols. By the same token, those people were probably speaking a complex language as well.
November 2003
  • Theories of consciousness based on Quantum Mechanics often use Bose-Einstein condensates (the most highly ordered structures in nature) as their building blocks (see this chapter of my book). The intriguing feature of a Bose-Einstein condensate is that the many parts of a system not only behave as a whole, they become whole. Their identities merge in such a way that they lose their individuality. If Bose-Einstein condensation occurs at body temperatures in brain cells (as predicted by Herbert Froehlich), then they could account for the most popular features of consciousness. In 1999, Debbie Jin of the University of Colorado (Boulder, USA) discovered a substance obtained by cooling a vapor of fermions (the basic building blocks of matter) to almost absolute zero: the "degenerate Fermi atomic gas". Now, researchers of Debbie Jin's group have synthesized a molecular Bose-Einstein condensate from such a degenerate Fermi gas. (This condensate is a step towards achieving superfluidity in a dilute gas of fermionic atoms, the equivalent of superconductivity in metals).
  • Cyrille de Joussineau at the University of Montpellier II (France) has observer cells that communicate their instructions to neighboring cells by growing "fingers" (filopodia) and thus "touch them". This fact is relevant for studies on "signaling": how cells signal to other cells. For example, during development (of an organ, of a limb, of a neural area) cells must signal to each other: they must coordinate what that particular region of the body will become. signaling over long distances can only happen if the "intermediaries" somehow cooperate. Some cells "signal" to other cells by releasing particular proteins ("morphogens") that encode instructions for other cells. Other cells (such as nerve cells) "signal" by touching their neighbors. Cyrille de Joussineau has discovered that the latter process is more widespread than originally believed. Signals can be sent over long distances by a chain of cells capable of growing filopodia, which are used both for moving around, for collecting information and (Cyrille de Joussineau's discovery) for sending signals. A list of research papers on cell signaling
  • Evolutionary biologist Russell Gray of the University of Auckland (New Zealand) is placing the origin of Indo-European languages in Turkey. The family tree of Indo-European languages indirectly tells the story of how Indo-European people (Indians, Persians, Greeks, Celts, etc) spread around the world. Figuring out the place where the oldest Indo-European language arose is equivalent to finding out where the Indo-Europeans originally came from. The traditional hypothesis (relying on archeological evidence) is that the Indo-Europeans originated 5-4,000 years BC from a region at the border between Asia and Europe, near the Ural Mountains. This "Kurgan" horsemen then migrated both east (Persia, India) and west (Europe). The new theory places the birth of the Indo-Europeans much earlier (7-6,000 BC) and in Anatolia (modern Turkey). It was not a population that migrated, but the language itself that migrated following the spread of agriculture. Farmers in Anatolia invented something so precious (farming) that it quickly spread both east and west, taking the language with it. Gray and his collaborators employed statistical methods: since the differences between words are a measure of how closely languages are related, then the rate of linguistic mutations (the rate at which words change) is a measure of how old the root of a linguistic family is. This statistical method shows that the most "distant" relative of modern Indo-European languages is the ancient language of the Hittites, invented between 8,000 and 10,000 years ago. This was much earlier than the time when the Hittites became a power: the language was not spread by force, but must have spread peacefully, as a by-product of a more advanced civilization.
October 2003
  • Inkha ("Interactive Neurotic King's Head Assembly") is a robot receptionist that works at King's College in London Inkha, driven by a number of motors controlled by a computer, is capable of moving in response to movement (as detected by cameras and sensors) She is an autonomous robot, so substantially different from the robots that perform repetitive tasks in an assembly line.
  • Jon Simons at the Institute of Cognitive Neuroscience of London is studying the interaction between the medial temporal lobe and the frontal lobe in long-term memory. The medial temporal lobe encodes, stores and retrieves long-term memories. The frontal lobe contributes to encoding and retrieval, but does not seem to participate in the storage/indexing of memories.
  • Ernst Fehr of the University of Zurich (Switzerland) is studying human altruism, a phenomenon that seems to defy the principles Darwinian competition. He contrasts "reciprocal altruists" (widely found in nature), that reward and punis cooperation or lack thereof based on their long-term interest, with "strong reciprocity", which is uniquely human, in which reward and punishment are largely independent of long-term interest. He believes that the solution to the apparent paradox of altruism lies in cultural evolution and gene-culture co-evolution. (Fehr's article for Nature).
  • Nature's focus on RNA interference collects a number of articles on the topic. RNA interference (RNAi) is a process (identified in plants and worms) that causes genes to be "silenced" so that they don't express themselves. This could have far-reaching applications in medicine.
  • William Ruddiman at the University of Virginia (Charlottesville, USA) has estimated the effects on climate of human activities from the beginning of agriculture (8,000 years ago) to today, and decided that deforestation and irrigation caused the release of enough greenhouse gases into the atmosphere to actually change weather patterns (rising the global temperature by an average of 0.8C, thus avoiding an impending ice age that never took place). Ruddiman examined records of greenhouse gases in ice cores dating back 400,000 years, and found that the cyclical fluctuations on planet Earth were altered starting about 8,000 years ago (carbon dioxide and methane into the atmosphere should have been declining steadily for the last 10,000 years, but instead have been rising for the last 8,000 and 5,000 years respectively). The correlation between solar radiation (caused by changes in the Earth's orbit) and methane in the atmosphere stopped working 5,000 years ago. Ditto for the rise of carbon dioxide (also now out of synch with solar radiation), which started 8,000 years ago (way before the industrial revolution). The only possible explanation for these two anomalies is human activity: deforestation caused the increase in carbon dioxide, and rice paddies and livestock caused the increase in methane. (Incidentally, the "little ice age" that started around 1300 and lasted a couple of centuries coincides with a reduction of agriculture, namely the plague that spread from China to Europe).
September 2003
  • Kun-Liang Guan of the Life Sciences Institute (Michigan, USA) has identified several groups of "guidance cues" (which are actually proteins such as netrins1-3, semaphorins4, 5, ephrins6-8 and Slits9) that guide neurons and axons to their appropriate destinations during brain development. The nervous system is manufactured through a lengthy process (both during the embryonic stage of the foetus and during the first few years of life) in which cells must migrate to their "correct" locations and axons have to create the "correct" connections. These two processes (neural migration and axon pathfinding) are guided by those "cues", which either either attract or repel axons and neurons.
  • Asish Basu of the University of Rochester and his colleagues claim that a meteor on Antarctica caused mass extinction of about 90% of life forms on Earth 250 million years ago (the Permian-Triassic boundary).
August 2003
  • A team led by Eric Lander at the Broad Institute (Boston, USA) is on its way to complete the sequencing of the chimp's genome. The chimp's genome is almost 99% identical to the human genome, but humans are obviously quite different from chimpanzees. Comparing the two genomes may help figure out what causes the huge difference between the two species.
July 2003
  • Since the circadian rhythms is basically the rhythm of day and night (sunlight and darkness), it has long been believed that the biological clock depends on exposure to light, and specifically on exposure "of the yes" to light. But Dan Oren, a psychiatrist at Yale University, has argued that blood is the messenger that carries the light signal from the skin to the brain. So Scott Campbell and Patricia Murphy of Cornell University Medical College have used bright light applied to the back of people's knees to reset the human internal clock. These experiments seem to confirm Oren's theory. The problem is that we don't quite know what causes and maintains the biological clocks. The hypothalamus is widely considered to be the location of the circadian pacemaker in mammals, but proteins called "cryptochromes", that are spread throughout the body, are involved in detecting changes in light and setting the body's clock.
    In 1998, both Joseph Takahashi's team at Northwestern University and Jeffrey Hall's team at Brandeis University demonstrated that the protein cryptochrome (the same protein that triggers plant growth by responding to light in the blue-to-ultraviolet part of the spectrum) acts as a transducer by which light drives the molecular machinery that generates circadian rhythm.
    Genetics is adding some interesting data. In 1971, the first circadian gene was discovered in the fruit fly. In 1997, Joseph Takahashi of Northwestern University discovered that the biological clock is related to the periodic expression of genes. Light, via a "photic entrainment pathway" (a series of photopigments and phototransduction pathways), triggers the clock genes. An increasing number of mammalian genes have been shown to be regulated by the clock genes. Once activated, the clock-controlled genes are expressed and are synthesised into proteins.
    We now know that "the fruit fly's clock consists of a core system of four regulatory proteins that interact to give the clock periodicity. The cycle begins when two of these proteins, CLOCK and CYCLE, bind together and increase the production of two other proteins, PER (periodic) and TIM (timeless), the levels of which slowly accumulate over time. When enough PER and TIM are made, they disable the CLOCK-CYCLE complex, slowing their own production and signaling the end of the cycle." ( "National Institute of Mental Health")
  • The team of David Julius' Lab at UC San Francisco is studying how we perceive heat, the chemical process that leads to the sensation of pain related to heat. This could lead to new clinical strategies for pain management.
  • Ardem Patapoutian and others at the Scripps Research Institute at La Jolla, California "thermosensation", the way we react to changes in temperature. They have identified the "thermoTRPs" (thermal Transient Receptor Potential ion channels) that transform thermal information into electrochemical signals to the brain. This transmission is mediated by the dorsal root ganglia along the vertebral column. The neurons of this ganglia are highly specialized to sense distinct ranges of temperatures, so that distinct groups of sensory neurons convey specific sensory information via dedicated pathways to the brain.
  • Researchers at the University of Southern California, Los Angeles (Mihail Bota, Hong-Wei Dong and Larry Swanson) have inaugurated a Knowledge Management System, the "Brain Architecture Management System" (BAMS), that will act as both a repository of information about brain structures of different species and a tool (an inference engine) for analyzing the architecture of brain networks. The system has been initialized with thousands of data collected from the scientific literature, particularly about the connections between brain regions.
  • The team of Laura Cousino Klein at Penn State University has found that nicotine withdrawal impairs time perception in smokers. Basically, they tested how well smokers and non-smokers estimate can estimate a time interval. Differences are minimal. But when smokers are kept from smoking for a day or so, they begin to make erroneous estimates, up to 50% shorter.
June 2003
  • Thanks to new technologies for scanning the brain, scientists at the Panum Institute of Copenhagen have been able to measure blood flow in the brain corresponding to both inhibitory and excitatory stimuli. Contrary to expectations, both kinds of stimuli cause blood flow in the brain to increase. This is a puzzling finding that probably means we don't really understand what we "read" in the brain's activity when we scan it.
May 2003
  • Audie Leventhal of the University of Utah claims that a shortage of the GABA neurochemical in the visual cortex causes the decline in visual functions that accompanies ageing. The problem would not be in the eye, but in the brain. More specifically, Leventhal claims that GABA-mediated inhibition in the visual cortex degrades with age, because somehow production of GABA tends to slow down as the organism gets older. The function of GABA seems to be to protect the brain from unnecessary overload of signals. When GABA declines, the brain is overwhelmed by signals that are actually confusing, to the point that it may not be able to "think" and "see" properly anymore. Incidentally, some tranquilizers (Valium, Xanax, Librium) do increase the levels of GABA in the brain, but no correlation with improved vision or thinking in older humans has ever been recorded.
  • The French neuroscientist Olivier Houde` is studying the neural foundations of logical and mathematical cognition (paper) in an attempt to clarify what logic and mathematics are (in our brain) and how they emerge and evolve.
March 2003
  • Researchers at the National Institute for Medical Research are studying why and how neurons decided that they have to stop dividing. In theory, cells should keep dividing forever. In practice, they seem to be programmed to stop dividing at some point in their life, and that "point" is what gives our nervous system its shape. There is some kind of self-regulation associated to neurons, and, since neurons are in principle all the same, that form of regulation must be specific to the region where they "reside". The researchers have determined how some embryonic neurons give rise to most of the neurons of the adult nervous system in the Drosophila larva. The results are intriguing, and still largely mysterious. Some proto-neurons divide for about 4 days and produce about 100 cells, whereas others divide for 22-40 hours and generate only 4-12 cells. The question, of course, is what tells a neuron "you are part of this region and therefore you are supposed to stop dividing right now".
January 2003
  • Jared Taglialatela and Sue Savage-Rumbaugh of Georgia State University report that they have been able to train a chimpanzee to use sounds for 'banana', 'grapes', 'juice' and 'yes'. Monkeys are obviously able to communicate via symbols, but this would be the first time that they can communicate via sounds (i.e., "speak"). Other chimpanzees have already communicated using sign language.
  • We know that the 'higher' cognitive skills of human beings are mainly due to the prefrontal cortex. Jacqueline Wood and Jordan Grafman of the National Institutes of Health in Bethesda (Maryland) believe that the representational "technique" used by the prefrontal cortex (rather than the processes that occur within it) can explain our ability to reason, speak, etc. In other words, it is the way we store our knowledge that enables us to do what we do with knowledge.
  • Samuel Weiss at the University of Calgary believes that prolactin, a hormone that is released after sexual intercourse and during pregnancy, causes the birth of new neurons in the brain.

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