Neuroscience

Major brain wiring claim is overturned? Challenges dogma?

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Old vs. new view

June 27, 2013 — A series of studies conducted by Randy Bruno, PhD, and Christine Constantinople, PhD, of Columbia University’s Department of Neuroscience, topples convention by showing that sensory information travels to two places at once: not only to the brain’s mid-layer (where most axons lead), but also directly to its deeper layers. The study appears in the June 28, 2013, edition of the journal Science.

For decades, scientists have thought that sensory information is relayed from the skin, eyes, and ears to the thalamus and then processed in the six-layered cerebral cortex in serial fashion: first in the middle layer (layer 4), then in the upper layers (2 and 3), and finally in the deeper layers (5 and 6.) This model of signals moving through a layered “column” was largely based on anatomy, following the direction of axons — the wires of the nervous system.

“Our findings challenge dogma,” said Dr. Bruno, assistant professor of neuroscience and a faculty member at Columbia’s new Mortimer B. Zuckerman Mind Brain Behavior Institute and the Kavli Institute for Brain Science. “They open up a different way of thinking about how the cerebral cortex does what it does, which includes not only processing sight, sound, and touch but higher functions such as speech, decision-making, and abstract thought.”

It sounds like we know both more and less than we did before, but that is probably a good place to begin, when studying the brain.

Note this however:

The study suggests that upper and lower layers of the cerebral cortex form separate circuits and play separate roles in processing sensory information. Researchers think that the deeper layers are evolutionarily older — they are found in reptiles, for example, while the upper and middle layers, appear in more evolved species and are thickest in humans.

Oh dear, where is that Kevin Padian when we need him? In what sense are modern mammals “more evolved” than modern reptiles?

Since we are here anyway: Reptiles vary greatly in intelligence; some reptiles are actually fairly smart. For that matter, so are some molluscs (but not others). Whatever this new find about the six layers of the cerebral cortex ends up meaning, we should avoid the unbidden mental image of a “tree of intelligence” (= all mammals are smarter than all reptiles; all vertebrates are smarter than all invertebrates, etc.) As far as intelligence is concerned, evolution simply does not work that way.

Journal Reference:

C. M. Constantinople, R. M. Bruno. Deep Cortical Layers Are Activated Directly by Thalamus. Science, 2013; 340 (6140): 1591 DOI: 10.1126/science.1236425

17 Replies to “Major brain wiring claim is overturned? Challenges dogma?

  1. 1
    bornagain77 says:

    This ‘holistic brain’ study reminded me of this ‘beyond belief’ study from a few years ago where:

    Human brain has more switches than all computers on Earth – November 2010
    Excerpt: They found that the brain’s complexity is beyond anything they’d imagined, almost to the point of being beyond belief, says Stephen Smith, a professor of molecular and cellular physiology and senior author of the paper describing the study: …One synapse, by itself, is more like a microprocessor–with both memory-storage and information-processing elements–than a mere on/off switch. In fact, one synapse may contain on the order of 1,000 molecular-scale switches. A single human brain has more switches than all the computers and routers and Internet connections on Earth.
    http://news.cnet.com/8301-2708.....2-247.html

    Dr. Torley had an article, based on the preceding study, suggesting they seriously underestimated the complexity of the brain:

    Could the Internet ever be conscious? Definitely not before 2115, even if you’re a materialist. – Dr. Torley – December 7, 2012
    Excerpt: So there you have it. A microprocessor with around 1 billion transistors is in the same mental ballpark as … a worm. Rather an underwhelming result, don’t you think?
    “What about the Internet as a whole?” you might ask. As we saw above, the number of transistors (N) in the entire Internet is 10^18, so log(N) is 18. log(Z) is log(2) or about 0.3, so C=(18*0.3)=5.4. That’s right: on Deamer’s scale, the complexity of the entire Internet is a miserable 5.4, or 40 orders of magnitude less than that of the human brain, which stands at 45.5.
    Remember that Deamer’s formula is a logarithmic one, using logarithms to base 10. What that means is that the human brain is, in reality, 10,000,000,000,000,000,000,000,000,000,000,000,000,000 times more complex than the entire Internet! And that’s based on explicitly materialistic assumptions about consciousness.
    http://www.uncommondescent.com.....terialist/

    This following study gives weight to Dr. Torley’s contention that they seriously underestimated the brain by ‘merely’ comparing it to all the computers and routers and Internet connections on Earth:

    Modular Biological Complexity – Christof Koch – August 2012
    Summary: Consider a neuronal synapse — the presynaptic terminal has an estimated 1000 distinct proteins. Fully analyzing their possible interactions would take about 2000 years. Or consider the task of fully characterizing the visual cortex of the mouse — about 2 million neurons. Under the extreme assumption that the neurons in these systems can all interact with each other, analyzing the various combinations will take about 10 million years…, even though it is assumed that the underlying technology (in computers used to try to understand the biological interactions) speeds up by an order of magnitude each year. ,,,
    Improved technologies for observing and probing biological systems has only led to discoveries of further levels of complexity that need to be dealt with. This process has not yet run its course. We are far away from understanding cell biology, genomes, or brains, and turning this understanding into practical knowledge.
    http://www.sciencemag.org/cont.....31.summary

    Moreover, despite having more molecular switches than all the computers routers and internet connections on earth, the brain is surprisingly frugal in its energy consumption:

    Does Thinking Really Hard Burn More Calories? – By Ferris Jabr – July 2012
    Excerpt: Unlike physical exercise, mental workouts probably do not demand significantly more energy than usual. Believing we have drained our brains, however, may be enough to induce weariness,,,
    Although the average adult human brain weighs about 1.4 kilograms, only 2 percent of total body weight, it demands 20 percent of our resting metabolic rate (RMR)—the total amount of energy our bodies expend in one very lazy day of no activity.,,,
    —Resting metabolic rate: 1300 kilocalories, or kcal, the kind used in nutrition
    —1,300 kcal over 24 hours = 54.16 kcal per hour = 15.04 gram calories per second
    —15.04 gram calories/sec = 62.93 joules/sec = about 63 watts
    —20 percent of 63 watts = 12.6 watts
    So a typical adult human brain runs on around 12 watts—a fifth of the power required by a standard 60 watt lightbulb. Compared with most other organs, the brain is greedy; pitted against man-made electronics, it is astoundingly efficient.
    http://www.scientificamerican......d-calories

    As well the brain is surprisingly constant in its energy consumption:

    THE EFFECT OF MENTAL ARITHMETIC ON CEREBRAL CIRCULATION AND METABOLISM
    Excerpt: Although Lennox considered the performance of mental arithmetic as “mental work”, it is not immediately apparent what the nature of that work in the physical sense might be if, indeed, there be any. If no work or energy transformation is involved in the process of thought, then it is not surprising that cerebral oxygen consumption is unaltered during mental arithmetic.
    – ncbi

    Appraising the brain’s energy budget:
    Excerpt: In the average adult human, the brain represents about 2% of the body weight. Remarkably, despite its relatively small size, the brain accounts for about 20% of the oxygen and, hence, calories consumed by the body. This high rate of metabolism is remarkably constant despite widely varying mental and motoric activity. The metabolic activity of the brain is remarkably constant over time.
    http://www.pnas.org/content/99/16/10237.full

    Moreover, the metabolic activity of the brain is, despite its not being a muscle, acts as if it is always doing an aerobic workout:

    Scaling of Brain Metabolism and Blood Flow in Relation to Capillary and Neural Scaling – 2011
    Excerpt: Brain is one of the most energy demanding organs in mammals, and its total metabolic rate scales with brain volume raised to a power of around 5/6. This value is significantly higher than the more common exponent 3/4 (Quarter Power Scaling) relating whole body resting metabolism with body mass and several other physiological variables in animals and plants.,,,
    Moreover, cerebral metabolic, hemodynamic, and microvascular variables scale with allometric exponents that are simple multiples of 1/6, rather than 1/4, which suggests that brain metabolism is more similar to the metabolism of aerobic than resting body. Relation of these findings to brain functional imaging studies involving the link between cerebral metabolism and blood flow is also discussed.,,
    General Discussion Excerpt:
    ,,It should be underlined that both CBF and CMR scale with brain volume with the exponent about 1/4 which is significantly different from the exponent 1/4 relating whole body resting specific metabolism with body volume [1], [2], [3]. Instead, the cerebral exponent 1/6 is closer to an exponent,, characterizing maximal body specific metabolic rate and specific cardiac output in strenuous exercise [43], [44]. In this sense, the brain metabolism and its hemodynamics resemble more the metabolism and circulation of exercised muscles than other resting organs, which is in line with the empirical evidence that brain is an energy expensive organ [10], [17], [18]. This may also suggest that there exists a common plan for the design of microcirculatory system in different parts of the mammalian body that uses the same optimization principles [45].,,
    http://www.ncbi.nlm.nih.gov/pm.....MC3203885/

    More the ‘metabolic optimization’ for the brain is found to scale across species:

    Scaling of Brain Metabolism with a Fixed Energy Budget per Neuron:
    Excerpt: This suggests that the energy budget of the whole brain per neuron is fixed across species and brain sizes,
    http://www.plosone.org/article.....ne.0017514

    The preceding experiments are very unexpected for Darwinian materialists since Darwinian materialists hold that ‘consciousness’ is merely a ’emergent property’ of the physical processes of the material brain. But why should ‘consciousness’ which is presupposed to be result of, and subservient to, the material processes of the brain constrain the material brain to operate at such a constant and optimal metabolic rate across species whereas the rest of body fluctuates in its metabolic activity? The most parsimonious explanation for such a optimal constraint on the brain’s metabolic activity, especially given that Darwinists cannot even account for how a single neuron arose much less an entire brain, is that the material brain was designed, first and foremost, to house consciousness and to give consciousness the most favorable metabolic environment possible at all times.

    Further notes:

    Alan Turing and Kurt Godel – Incompleteness Theorem and Human Intuition – video (notes in video description)
    http://www.metacafe.com/watch/8516356/

    Are Humans merely Turing Machines?
    https://docs.google.com/document/d/1cvQeiN7DqBC0Z3PG6wo5N5qbsGGI3YliVBKwf7yJ_RU/edit

  2. 2
    bornagain77 says:

    Of related note from ENV:

    Project Brain: Our Prediction – June 28, 2013
    Excerpt: The goal of the Human Brain Project is to provide the most detailed simulation ever of the complexity of human brain. The computing power for this will require super-computers thousands of times more powerful than what we have available today. So an aim of the larger research initiative is to develop computers with that kind of power.,,,
    Our prediction? Simply this. Much as in the case of the human genome, the study of the physical makeup of the brain will provide remarkable insight into its components and structure. However it will also unlock layers upon layers of (unfathomable) complexity.
    http://www.evolutionnews.org/2.....73831.html

  3. 3
    bornagain77 says:

    Of related interest to the lead off ‘holistic brain’ study referenced by News in the OP:

    Self-awareness in humans is more complex, diffuse than previously thought – August 22, 2012
    Excerpt: Self-awareness is defined as being aware of oneself, including one’s traits, feelings, and behaviors. Neuroscientists have believed that three brain regions are critical for self-awareness: the insular cortex, the anterior cingulate cortex, and the medial prefrontal cortex. However, a research team led by the University of Iowa has challenged this theory by showing that self-awareness is more a product of a diffuse patchwork of pathways in the brain – including other regions – rather than confined to specific areas. The conclusions came from a rare opportunity to study a person with extensive brain damage to the three regions believed critical for self-awareness. The person, a 57-year-old, college-educated man known as “Patient R,” passed all standard tests of self-awareness. He also displayed repeated self-recognition, both when looking in the mirror and when identifying himself in unaltered photographs taken during all periods of his life. “What this research clearly shows is that self-awareness corresponds to a brain process that cannot be localized to a single region of the brain,”,,,
    http://medicalxpress.com/news/.....ously.html

  4. 4
    Robert Byers says:

    The brain, the brain. its all about the evolutionary presumption. fighting the historical christian assumption of the soul as the intelligence source, that the brain is our intelligence.
    It isn’t. It just is a middleman from the soul to the body. Yes its complex because the soul needs a complex middleman.
    There is no evidence the brain is anything other then a dumb machine.
    Its just lines of reasoning to think otherwise.
    Apes and cows brains are probably just as complex as ours.
    Do they think they could make a computer as smart as a a cow?
    If not a human! What would it be like!

  5. 5

    Say that that one extant organism is “more evolved” than another is almost meaningless, and certainly ambiguous.

    And to say that one brain is “more evolved” than another, even more so. Is a penguin flipper more or less evolved than an albatross wing?

    So often criticisms of evolutionary theory are based on a concept of evolution that “evolutionists” don’t actually have. We don’t think that evolution is progression from “less evolved” modern bacteria to “greatly evolved” human beings.

    We think evolution is a process of adaptation to the environment (as well of course as drift). So a population that is less well adapted to its environment, and still rapidly adapting, you might say is “less evolved” than a population that has been at an optimum for millions of generation. In that sense human beings are much less “evolved” than, say, modern bacteria, or crocodiles, or sharks.

    But the same amount of evolving has gone on (well, more in the case of bacteria, because they breed so much faster).

    Evolution isn’t a ladder, it’s a process of adaptation and diversification. The reason modern organisms include more complex organisms than ancient organisms is simply that if you start simple, and vary, there’s more scope for more complex than less. There’s a floor, but no ceiling.

  6. 6
    News says:

    Elizabeth Liddle, the authors were not criticizing evolution, they were representing it as they honestly believe to be and they are as fully evolutionists as you are. I don’t expect you to understand or agree with this, but that is one of a growing list of problems. – O’Leary

  7. 7

    I was just challenging the term “more evolved” comment, Denyse. It certainly makes sense to talk about things being “evolutionarily old”, but to talk about extant species being “more evolved” than other extant species, is misleading. I agree it was their term, and you commented on it. I’m trying to clarify.

    I’m actually agreeing with you. You say:

    Whatever this new find about the six layers of the cerebral cortex ends up meaning, we should avoid the unbidden mental image of a “tree of intelligence” (= all mammals are smarter than all reptiles; all vertebrates are smarter than all invertebrates, etc.) As far as intelligence is concerned, evolution simply does not work that way.

    No, it doesn’t. I don’t think Bruno et al do either, but they spoke carelessly when they used the term “more evolved species”. What they mean (surely) is “species with phylogenetically more recent brain organisation”.

    But I’m still not clear what problem you think has been added to your “growing list” – could you elaborate?

    Also, Sakmann’s comment that “The prevailing view that the cortex is a collection of monolithic columns, handing off information to progressively higher modules, is an idea that will have to go.” seems very odd! It “went” a very long time ago! This is the problem with press releases. People (especially press officers) always want to make the new research seem radical and “game changing”. It usually isn’t – and if it is, it’s often wrong! Science is tediously incremental. Well, not tedious to the scientists, but tedious to press officers.

  8. 8
    Barb says:

    Dr. Liddle writes,

    So often criticisms of evolutionary theory are based on a concept of evolution that “evolutionists” don’t actually have. We don’t think that evolution is progression from “less evolved” modern bacteria to “greatly evolved” human beings.

    Organic evolution, as I have been taught, is the theory that the first living organism developed from nonliving matter; then, as it reproduced, it changed into different types of living things via the mechanisms of natural selection and mutation.

    We think evolution is a process of adaptation to the environment (as well of course as drift).

    You seem to be using a logical fallacy known as “moving the goalposts”. You claim evolution has nothing to do with the origin of life, but rather with the adaptation of life to various environments.
    Here is what the Science Channel thinks evolution is:

    The theory of evolution seeks to explain the origin of life on Earth and the origin of different species. Despite the fact that most of the scientific community has regarded it as fact for more than a century, a large number of people still dispute the theory of evolution, and various public controversies have resulted from this disagreement.
    According to evolutionary theory, life began billions of years ago, when a group of chemicals inadvertently organized themselves into a self-replicating molecule. This tiny molecule gave rise to everything that has ever lived on the planet. Different and more complex organisms grew from this simple beginning through mutation of DNA and natural selection.

    (http://curiosity.discovery.com.....-evolution)
    This is one of the major problems with evolutionary theory, in my opinion; scientists themselves don’t agree on what exactly it is. Either it has to do with the origin of life (the book is titled “On the Origin of Species…”) or it does not.

  9. 9
    Alan Fox says:

    Organic evolution, as I have been taught, is the theory that the first living organism developed from nonliving matter; then, as it reproduced, it changed into different types of living things via the mechanisms of natural selection and mutation.

    Unfortunately, you were taught incorrectly. Evolutionary theory cannot and does not attempt to explain the origin of life. It attempts to explain the diversity of life as found today and in the past. It is a prerequisite for the theory that self-sustaining self-replicators (the simplest possible living organisms) are in place. Then the process of adaptation to the niche environments that come and go by the reiteration of selection by the environment via differential survival of alleles, the variation of which is constantly being added to by mutation and other processes such as recombination and duplication, symbiogenesis, horizontal gene transfer, can begin.

  10. 10
    Alan Fox says:

    PS @ Barb

    The Science Channel has it wrong.

    The statements

    The theory of evolution seeks to explain the origin of life on Earth

    and

    According to evolutionary theory, life began billions of years ago, when a group of chemicals inadvertently organized themselves into a self-replicating molecule. This tiny molecule gave rise to everything that has ever lived on the planet.

    are incorrect.

    The origin of life on Earth is still a complete mystery, though there are many hypotheses. The evidence of what happened on Earth 2- 3 billion years ago that resulted in the first living things is no longer available and I doubt we’ll ever be certain how it happened unless evidence of life elsewhere turns up. Then all bets are off.

  11. 11
    Joe says:

    Alan Fox:

    Evolutionary theory cannot and does not attempt to explain the origin of life.

    Then it has nothing to say about its diversity as the origins and diversity are directly linked.

    If life was designed then it was designed to evolve and evolved by design.

    Why are evos so dull that they cannot grasp that simple fact?

  12. 12
    Barb says:

    Thanks for responding, Alan. You state:

    Unfortunately, you were taught incorrectly. Evolutionary theory cannot and does not attempt to explain the origin of life.

    Then a lot of high school and college level textbooks should be changed. This also goes for the Science Channel’s website.

  13. 13
    Alan Fox says:

    Then a lot of high school and college level textbooks should be changed. This also goes for the Science Channel’s website.

    If they suggest that evolutionary theory offers an explanation of life’s origin, yes, they should. At least a correction slip could be pasted in.

    Is this the Science Channel? I doubt they’ll listen to a layperson from France but I’ll try. Can you post a link to the quotes?

  14. 14
    keiths says:

    Alan Fox:

    Evolutionary theory cannot and does not attempt to explain the origin of life.

    Joe:

    Then it has nothing to say about its diversity as the origins and diversity are directly linked.

    If life was designed then it was designed to evolve and evolved by design.

    Why are evos so dull that they cannot grasp that simple fact?

    The dullness is yours, Joe.

    You might as well claim that what Kepler did wasn’t astronomy because he couldn’t explain the origin of stars and planets.

  15. 15
    keiths says:

    Barb,

    This is one of the major problems with evolutionary theory, in my opinion; scientists themselves don’t agree on what exactly it is. Either it has to do with the origin of life (the book is titled “On the Origin of Species…”) or it does not.

    The origin of life and the origin of species are separate questions. Evolutionary theory explains the latter, but not the former.

  16. 16
    Joe says:

    keiths:

    You might as well claim that what Kepler did wasn’t astronomy because he couldn’t explain the origin of stars and planets.

    Nope, not even close.

    If living organisms were designed then it is obvious they were designed to evolve and evolved by design. That is because it takes too much work to get a habitable planet and organisms just to let them go on by chance.

    Again the only way darwinian mechanisms rule over evolution is if blind and undirected processes produced living organisms from non-living matter.

    And nothing the ignorant evos can say will ever change that. The OoL is key to its subsequent diversity.

    Nest the evos will tell us that sure Stonehenge was designed but its alignment is just chance.

  17. 17
    Joe says:

    keiths:

    The origin of life and the origin of species are separate questions. Evolutionary theory explains the latter, but not the former.

    1- There isn’t any “evolutionary theory”

    2- If it cannot explain the OoL then it has nothing to say about its diversity as the two are directly linked.

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