Syncopated Ghost Whispers Haunt Your Internal Web

Long Distance Brain Network Macaque PNAS
Above, you see an early depiction of the "long distance network" of the brain, connecting different brain centres with each other. The complex visualisation was compiled using information obtained from the study of the macaque brain.

The Human Connectome Project is hard at work producing images such as this, using an MRI technique known as diffusion tensor imaging.

With 100 billion neurons, each with around 10,000 connections, mapping the human brain will be no easy feat, and charting every single connection could take decades. The HCP will tackle the lowest hanging fruit first: charting the major highways between different brain regions, and showing how these connections vary between individuals. To do this they will combine several imaging tools including something called diffusion MRI, which maps the structure of the white matter that insulates the "wires" of the brain, and also resting-state MRI, which measures how brain regions oscillate in unison as a result of shared connections. _NewScientist

Cortical parcellations (PDF) such as the above, use another MRI technique. This method of brain visualisation separates different cortical domains which serve particular functions.

These brain images are presented for purposes of orientation and grounding. They may help to picture the various nodes and connections presented in the abstracted images and schematics.

Above, you see some of the brain areas involved in three important brain networks: Default Mode, Salience, and Central Executive. When viewing such fMRI "activation" images, it is helpful to mentally superimpose the connections between the activated brain centres. More on the three pictured networks:

The default mode (DMN) or default brain network (shown in blue) is what your brain does when not engaged in specific tasks. It is the busy or active part of your brain when you are mentally passive. According to Bresslor and Brennon the “DMN is seen to collectively comprise an integrated system for autobiographical, self-monitoring and social cognitive functions.” It has also been characterized as responsible for REST (rapid episodic spontaneous thinking). In other words, this is the spontaneous mind wandering and internal self-talk and thinking we engage in when not working on a specific task or, when completing a task that is so automatized (e.g., driving a car) that our mind starts to wander and generate spontaneous thoughts.

...The salience network (shown in yellow) is a controllor or network switcher. It monitors information from within (internal input) and from the external world arounding us, which is constantly bombarding us with information. Think of the salience network as the air traffic controllor of the brain. Its job is to scan all information bombarding us from the outside world and also that from within our own brains. This controller decides which information is most urgent, task relevant, and which should receive priority in the que of sending brain signals to areas of the brain for processing.

...Finally, the central-executive network (CEN; shown in red) “is engaged in higher-order cognitive and attentional control.” In other words, when you must engage your concious brain to work on a problem, place information in your working memory as you think, focus your attention on a task or problem, etc., you are “thinking” and must focus your controlled attention. _BrainClockBlog

We have talked about the default mode network previously, and will devote future time to the integration of various overlapping -- as well as mutually exclusive -- networks.

Now, we are getting close to the "brass tacks" of how separate brain nodes communicate synchronously with each other via the connectome. The brain functions as a hierarchical network, and depends upon analogous -- but different -- mechanisms of ensemble activity at different levels of the hierarchy.

... when multiple neurons spread all over the brain are tuned in to a specific pattern of electrical activity at a specific frequency, then whenever that global activity pattern occurs, those neurons can act as a coordinated assembly."
The researchers pointed out that this mechanism of cell assembly formation via oscillatory phase coupling is selective. Two neurons that are sensitive to different frequencies or to different spatial coupling patterns will exhibit independent activity, no matter how close they are spatially, and will not be part of the same assembly. Conversely, two neurons that prefer a similar pattern of coupling will exhibit similar spiking activity over time, even if they are widely separated or in different brain areas. _SD

One of the many things that makes understanding the brain so difficult, is the fact that so many things are happening all at once, on so many different levels -- both in serial and parallel format. Almost all of the things that go on in the brain occur on the unconscious or subconscious levels. Consciousness, as we know it, is something of an over-rated evolutionary accident.

Video via Kevin at Brain Clock Blog

Finally, watch ghostly whispers moving through the human brain as it is put through its paces.

More information on brain networks at The Brain Clock Blog: The brain as a set of networks: Fine tunning your networks

Which One Are You? The 12 Talking Brains Inside Your Head

As part of an ongoing effort to map the human "connectome" – the full network of connections in the brain – Martijn van den Heuvel of the University Medical Center in Utrecht, the Netherlands, and Olaf Sporns of Indiana University Bloomington scanned the brains of 21 people as they rested for 30 minutes.

The researchers used a technique called diffusion tensor imaging to track the movements of water through 82 separate areas of the brain and their interconnecting neurons. They found 12 areas of the brain had significantly more connections than all the others, both to other regions and among themselves.

"These 12 regions have twice the connections of other brain regions, and they're more strongly connected to each other than to other regions," says Van den Heuvel. "If we wanted to look for consciousness in the brain, I would bet on it turning out to be this rich club," he adds. _NewScientist

These twelve brain activity centres -- six on each side of the brain -- are very fastidious about the information they will accept for processing. They refuse to accept raw sensory data, preferring rich, highly processed and refined information instead.

Here are the six hubs that each of your two brain halves possess:

Best connected of all is the precuneus, an area at the back of the brain. Van den Heuvel says its function is not well understood, but thinks that it acts as an "integrator region" collating high-level information from all over the brain.

Another prominent hub is the superior frontal cortex, which plans actions in response to events and governs where you should focus your attention. The superior parietal cortex – the third hub – is linked to the visual cortex and registers where different objects in your immediate vicinity are.

To bring memory into the equation, the hippocampus is another hub – that's where memories are processed, stored and consolidated. The fifth member of the club is the thalamus, which, among other things, interlinks visual processes; the last member, the putamen, coordinates movement.

Together the hubs enable the brain to constantly assess, prioritise and filter incoming information, and then puts it all together to make decisions about what to do next. _NewScientist

New Scientist
It is best to consider these hubs as central starting points in a complex and redundant maze of activity, that has no beginning and no end. Understanding how these centres communicate among themselves should provide cognitive scientists with a significant foundation for expanding the ideas of consciousness beyond their current human limits.

"The human brain is extraordinarily complex, yet it works efficiently, and a major challenge has been to discover principles of brain wiring and organisation that explain this," says Randy Buckner, a neuroscientist at Harvard University.

"What Van den Heuvel and Sporns show is that some regions of the brain are embedded in densely connected networks – so-called rich clubs – that may act together as a functional unit," says Buckner. "Such an organisation might help explain how complex networks of brain regions can work together efficiently." _NS

The above researchers at Utrecht and Indiana simulated a brain based upon the discovered connectivity, and learned that when one hub went down, it could take down the other hubs -- like a cascading network failure.

This is a particularly fertile area of brain research, which is likely to spawn a large number of diverging discoveries of importance.

IQ and HBD Deniers Being Backed Into a Corner

The project is novel in its size; most brain-imaging studies have looked at tens to hundreds of brains. Scanning so many people will shed light on the normal variability within the brain structure of healthy adults, which will in turn provide a basis for examining how neural "wiring" differs in such disorders as autism and schizophrenia.

The researchers also plan to collect genetic and behavioral data, testing participants' sensory and motor skills, memory, and other cognitive functions, and deposit this information along with brain scans in a public database (although the patients' personal information will be stripped out). Scientists around the world can then use the database to search for the genetic and environmental factors that influence the structure of the brain. _TR

Technology Review provides more information on the Human Connectome Project, sponsored by NIH. The ambitious project aims to do far more than to build more accurate maps of the human brain connectome. This project aims to do some genuine cognitive science. And that is likely to make a lot of HBD (human biodiversity) deniers very nervous.

"We want to learn as much as we can, not only about the typical patterns of brain connectivity, but also about the differences in wiring that make each of us a unique individual," says David Van Essen, a neuroscientist at Washington University in St. Louis, who is one of the project leaders. "If you're good at math, and I'm better at certain types of memory, can we identify some of the wiring characteristics that account for those differences?"

The most detailed studies to date of the neural circuits that connect one brain cell to another have focused on animal brains, because scientists can examine the animals' living tissue cells and their networks under a microscope. "We don't know how our species specifically is wired up," says Michael Huerta, associate director of the Division of Neuroscience and Basic Behavioral Science at the National Institute of Mental Health, and director of the Connectome project. "There is an entire class of data that is missing from neuroscience that is fundamentally important for how the brain works and how it breaks down in different disorders." And because researchers will be scanning only identical and fraternal twins and their siblings, the scientists can get a sense of the role that genetics and environment play in shaping brain structure. Structures of the brain that are highly dictated by genes will be more similar in identical twins than in fraternal twins, for example. _TR

There are more technical details at the link above. It promises to be a fascinating project on many levels.

Perhaps the scientists involved in the huge project have not yet taken the pledge of strict political correctness. Perhaps they have not gotten the memo directing them to avoid any research which might be used to explain cognitive or behavioural differences on the basis of genetics.

All issues of political correctness aside, the modern tools of science and computation are giving us the potential to finally understand many aspects of ourselves which had been closed to us. Some of these things may prove unsavoury, but in order to wisely move into the future we must be honest about our past and present.

The Brain: Wired and Introspective

ImageSource

The brain contains tens of billions of neurons, and trillions of synaptic connections (plus unknown numbers of other types of connections). Scientists from several universities are collaborating in an attempt to improve our understanding of the brain's "wiring diagram." At its best, it will still be crude compared to the real thing, but it's a start.

Working with $30 million and just half a decade, the Human Connectome Project aims to create a first-of-its-kind map of the brain’s complex circuitry, detailing every connection linking thousands of different regions of the brain.

The team consists of 33 researchers at nine different institutions, including Washington University School of Medicine in St. Louis and the University of Minnesota, the lead universities in the effort and the sites where much of the brain-scanning will take place. Their success will depend in part on another HCP grant to another research consortium headed up by Massachusetts General Hospital and UCLA that will develop advanced, custom brain scanners with higher spatial resolution and increased sensitivity. The funds themselves come from various bodies within the National Institutes of Health.

How big is the project? It’s at least 90 billion neurons big, but that doesn’t even convey the enormity and complexity of the human brain. There are something like 150 trillion synapses – the connections between neurons across which signals pass – that electrical signals must negotiate. These neurons and the connections between them make up the circuitry of the brain, and the HCP aims to create a better picture of that circuitry than we’ve ever had before. _PS

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But brain researchers cannot sit around on their hands until others provide them with a more detailed map of the brain. They must continue to muddle through with what they've got, in trying to understand how the brain creates the world. One interesting aspect of brain function is the variation in accuracy between different persons' judgement of the accuracy of their own educated guesses. Scientists at University College London looked at this question of introspective accuracy recently.

A specific region of the brain appears to be larger in individuals who are good at turning their thoughts inward and reflecting upon their decisions, according to new research published in the journal Science. This act of introspection -- or "thinking about your thinking" -- is a key aspect of human consciousness, though scientists have noted plenty of variation in peoples' abilities to introspect...

...To begin, Fleming and Weil recruited 32 healthy human participants and showed them two screens, each containing six patterned patches. One of the screens, however, contained a single patch that was brighter than all the rest. The researchers asked the participants to identify which screen contained the brighter patch, and then to rate how confident they felt about their final answer. After the experiment, participants' brains were scanned using magnetic resonance imaging, or MRI.

Fleming and the researchers designed the task to be difficult, so that participants were never completely sure if their answer was correct. They reasoned that participants who are good at introspection would be confident after making correct decisions about the patch, and less confident when they were incorrect about the patch. By adjusting the task, the researchers ensured all of the participants' decision-making abilities were on par with each others'—only the participants' knowledge of their own decision-making abilities differed.

"It's like that show, 'Who Wants to Be a Millionaire?'" said Weil. "An introspective contestant will go with his or her final answer when they are quite sure of it, and perhaps phone a friend when they are unsure. But, a contestant who is less introspective would not be as effective at judging how likely their answer is to be correct."

So, although each participant performed equally well at the task, their introspective abilities did vary considerably, the researchers confirmed. By comparing the MRI scans of each participant's brain, they could then identify a correlation between introspective ability and the structure of a small area of the prefrontal cortex. An individual's meta-cognitive, or "higher-thinking," abilities were significantly correlated with the amount of gray matter in the right anterior prefrontal cortex and the structure of neighboring white matter, Rees and his team found.

...The new study will be published in the 17 September issue of the journal Science. Science is published by AAAS, the nonprofit science society. _PO

This variation of introspective accuracy and depth is likely to play a crucial role in the development of cultures and civilisations. There should be little question that both environment and genetics play a role in the ultimate complexity of the pre-frontal cortex and other cortical and sub-cortical centers which are involved. Testing the participants additionally for both IQ and executive functions (EF) would almost certainly reveal strong correlations between the three concepts.

Thinkers who develop complex cognitive structures must be able to "hold" multiple thoughts in their heads simultaneously, while weighing the "fitness" of slight variations in the cognitive models. These models must often be of a dynamic nature -- particularly for engineers and scientists of several types.

Popular culture tends to downplay the importance of the mental skills of top-level theorists and explorers of knowledge fields, but these are the people who determine the ongoing prosperity and security of a civilisation over time.

Western civilisation is going through a period of time when generations worth of capital is being skimmed and scavenged by a de facto ruling class, which values political correctness over real world validity -- as a matter of ruling class survival. That is too, too bad for the rest of us, who very much need for our institutions to be under the discipline of real world checks and balances....


Given how badly the ruling class is fucking up, I am mulling over a series of posts on the topic of "peaceful insurrection." You may want to consider what that term might mean. Hint: I am referring to something a bit more determined and forceful than the "Tea Party" type of anti-big-government political movement. Yet still peaceful. How can that be? More later.

A Complex Puzzle in Dynamic 3D

Neuroscientists are far from understanding how the brain works. Faulty assumptions are falling like trees in a timber-cutting contest -- but at least in neuroscience, scientists are generally free to do research without politicians-holding-pursestrings looking over their shoulders. And so we learn -- as science is supposed to do -- by testing and destroying the hard-won work of others who came before.

Researchers from the University of Maryland are unraveling more of the seemingly chaotic nature of the cerebral cortex:

All our knowledge of how the brain really works has been based on taking a small sampling of all available neurons and making inferences about how the other neurons respond, Dr. Kanold explains. "This is like showing someone who wants to know how America looks, 'Here is one person from New York City and one person from California.' You don't get a very good picture of what the country looks like from that sampling," says Kanold, originally from Germany.

In contrast, Kanold and colleagues were able to look at the activity of all the neurons in a large region of the auditory cortex simultaneously. To get the highest resolution picture to date of how auditory cortex neurons are organized, the researchers used a technique to fill neurons in living mice with a dye that glows brightly when calcium levels rise, a key signal that neurons are firing. They then selectively illuminated specific regions of the cortex with a laser and measured the neuronal activity of hundreds of neurons in response to stimulation by simple tones of different frequencies. _SD

Scientists from Germany, the UK, and the US worked together to unravel a small piece of the 3D dynamic brain function puzzle:

Tolias, who is also on the staff at with the Michael E. DeBakey Veterans Affairs Medical Center, said, "If you were to eavesdrop on the activity of a neuron in the visual part of the brain while a person is looking at a picture over and over again, the neuron will respond differently each time. In other words, a substantial part of the activity is unrelated to the picture itself. It is this activity that was believed to be common among many adjacent neurons because they are densely interconnected."

"Here is where problems begin to arise," Tolias said. "If the activity that is unrelated to the picture is common to many cells, it would build up from one stage of processing to the next, ultimately dominating brain activity and making information processing impossible -- a scenario called runaway synchrony."

To find an answer to this paradox, Tolias and his colleagues, including Alexander S. Ecker, the paper's first author who is a graduate student in Tolias' lab at BCM and the Max Planck Institute for Biological Cybernetics in Tübingen, Germany developed a new technology that allowed more precise measurement of action potentials. They found that the groups of neurons believed to be reacting in a related fashion actually had a weak relationship. They were reacting on their own, not dependent on each other.

"We measured correlations in awake, behaving primates, allowing us to have control of the experimental conditions. This gave us the chance to eliminate the possibility of a number of artifacts affecting our measurements," Ecker said. "For recording, we used chronically implanted multi-tetrode arrays -- a technique that offered us the chance to monitor many neurons at extremely high recording quality."

...The testing involved a variety of visual stimulation ranging from bars and grating to natural images. The groups of neurons tested were physically close to each other with highly overlapping receptive fields and all receiving strong common input.

One reason Tolias believes the neurons behave without correlation is to allow information to be sent through the brain in the most efficient way possible.

"Such a mechanism that allows the decorrelation might be a crucial prerequisite to prevent small correlations from accumulating and dominating network activity along the visual hierarchy," Ecker said.

The "decorrelated state" may also have other benefits, Tolias added. "Information processing in the brain is much easier if nerve cells' activity is uncorrelated. If one level of the hierarchy wants to know what the previous area is doing, it can simply forget about correlations in this case. Otherwise, it has to perform more complex computations to get to the same result." _ScienceDaily

Interesting looks at "uncorrelated activity" of neighboring neurons in both the auditory and visual cortices. It has been difficult to achieve this level of dynamic resolution in the past, when monitoring neuronal activity in the cortex.

The problem is one of scale: there are too many neurons in the cortex, too tightly packed together, to allow a complete monitoring of even a very small section of cortex. The finding would have been made long ago, if neuroscientists had only possessed a finer means of neuro-electrical monitoring.

Do we want to know how the brain works? If we want to build human-equivalent machine intelligences, we had better want to know. The various gung-ho projects to "reverse-engineer" the brain and to use "biomimetic" approaches to building machine brains, are all walking on foundations of air at this time. And if that is true, you know that the even more ad-hoc approaches being taken by most computer scientists and electrical engineers are even farther off the mark, and less likely to succeed in reaching human-equivalence.

Even the best of tools to study the brain's "connectome" are clumsily crude and inept. But how precise do we need to be? After all, human brains vary wildly in their knowledge, wisdom, intelligence, creativity, and competence. How can we know that we are "copying" a "better brain?" At this time we are not even close to being able to make that distinction.

As to the study described in the newsrelease above, Al Fin Neuroscientists can only say "I could have told them that!" And yet, science has to take these slow, plodding steps in order to make tomorrow's needful paths of study more clear.

If only climate science had been able to avoid a political takeover so early in its infancy. We might have avoided so much of the current popular and political insanity that has gripped Europe, North America, and Oceania. Better to be slow, plodding, and well-supported by observable data, than to be flamboyantly and Nobel Prize winningly wrong.

Modified 10Feb10 with additional content and editing.