Central Pattern Generators Out of the Gait

Animals with 4 or more legs tend to utilise various gait patterns of locomotion, shifting from one to another effortlessly to save energy. Now, scientists at Max Planck Institute and Bernstein Center for Computational Neuroscience Göttingen, the Physics Department of the Georg-August-University of Göttingen are using central pattern generators (CPGs) in robots, to allow similar gait-shifting. In fact, they have managed to control multiple gaits using just one CPG!

In humans and animals, periodically recurring movements like walking or breathing are controlled by small neural circuits called "central pattern generators" (CPG). Scientists have been using this principle in the development of walking machines. To date, typically one separate CPG was needed for every gait. The robot receives information about its environment via several sensors - about whether there is an obstacle in front of it or whether it climbs a slope. Based on this information, it selects the CPG controlling the gait that is appropriate for the respective situation.

One single pattern generator for many gaits

The robot developed by the Göttingen scientists now manages the same task with only one CPG that generates entirely different gaits and which can switch between these gaits in a flexible manner. This CPG is a tiny network consisting of two circuit elements. The secret of its functioning lies in the so-called "chaos control". If uncontrolled, the CPG produces a chaotic activity pattern. This activity, however, can very easily be controlled by the sensor inputs into periodic patterns that determine the gait. Depending on the sensory input signal, different patterns - and thus different gaits - are generated.

The connection between sensory properties and CPG can either be preprogrammed or learned by the robot from experience. The scientists use a key example to show how this works: the robot can autonomously learn to walk up a slope with as little energy input as possible. As soon as the robot reaches a slope, a sensor shows that the energy consumption is too high. Thereupon, the connection between the sensor and the control input of the CPG is varied until a gait is found that allows the robot to consume less energy. Once the right connections have been established, the robot has learned the relation between slope and gait. When it tries to climb the hill a second time, it will immediately adopt the appropriate gait. _MaxPlanckSociety

 Even simple insects use different gaits to conserve energy.  Being able to program such energy-saving hacks into multi-legged robots should lead more quickly to autonomous roving robots capable of "living off the land" while achieving extended missions.  Living off the land might mean operating on solar energy or even eating forms of carbon such as plants, coal, or peat.

Central pattern generators are useful circuits, only algorithmic in a definitional way.  CPGs are generally seen as automatised motor controls for muscles, but it is likely that similar circuits contribute to cognitive functions at a low level.

Rodney Brooks must be loving this.

Rat Cortical Column Simulation Update: From Here to an Artificial Brain?

One of the holy grails of neuroscience is the creation of an accurate simulation of mammalian brain cortex. Swiss researchers have been working on the "Blue Brain" project since 2005, and are collaborating with IBM researchers to simulate the neocortex.

By mimicking the behavior of the brain down to the individual neuron, the researchers aim to create a modeling tool that can be used by neuroscientists to run experiments, test hypotheses, and analyze the effects of drugs more efficiently than they could using real brain tissue.

The model of part of the brain was completed last year, says Markram. But now, after extensive testing comparing its behavior with results from biological experiments, he is satisfied that the simulation is accurate enough that the researchers can proceed with the rest of the brain.

"It's amazing work," says Thomas Serre, a computational-neuroscience researcher at MIT. "This is likely to have a tremendous impact on neuroscience."

TechReview

The neocortical column is considered the functional building block of the mammalian cortex--a logical unit of brain organisation to begin a useful brain simulation project.

The project began with the initial goal of modeling the 10,000 neurons and 30 million synaptic connections that make up a rat's neocortical column, the main building block of a mammal's cortex. The neocortical column was chosen as a starting point because it is widely recognized as being particularly complex, with a heterogeneous structure consisting of many different types of synapse and ion channels. "There's no point in dreaming about modeling the brain if you can't model a small part of it," says Markram.

The model itself is based on 15 years' worth of experimental data on neuronal morphology, gene expression, ion channels, synaptic connectivity, and electrophysiological recordings of the neocortical columns of rats. Software tools were then developed to process this information and automatically reconstruct physiologically accurate 3-D models of neurons and their interconnections.

The researchers now think they have their neocortical column model well enough perfected to begin working on an entire mammalian "brain." They think they can model a mammalian brain realistically within 3 years, but respected neuro-researcher Christof Koch says "not so fast!"

However, none of these results have so far been published in the peer-reviewed literature, says Christof Koch, a professor of biology and engineering at Caltech. And this is by no means the first computer model of the brain, he points out. "This is an evolutionary process rather than a revolutionary one," he says. As long ago as 1989, Koch created a 10,000-neuron simulation, albeit in a far simpler model.

Furthermore, Koch is skeptical about how quickly the brain model can progress. Any claims that the human brain can be modeled within 10 years are so "ridiculous" that they are not worth discussing, he says.

Rat brains have about 200 million neurons, while human brains have in the region of 50 to 100 billion neurons. "That is a big scale-up," admits Markram.

source

The simulation is at a cellular level, and the researchers want to go deeper to the molecular level. This will put a tremendous strain on the computational infrastructure of the system. And it is not clear what is to be gained at this early stage by going to molecular resolution. Particularly when the cortical function appears to be at least partially based upon oscillatory phase-locking of assembles of neurons, such as columns and columnar groups.

Perhaps the Swiss researchers' "bottom-up" approach, combined with "top-down" approaches by people such as Jeff Hawkins, will begin to simulate some of the function of the human neocortex within the next 15 years. Perhaps.

Electromagnetic Brain Stimulation: More on TMS as Depression Treatment

Electromagnetic brain stimulation has been used for Parkinson's,... Alzheimer's,... Tourette's,...dystonia,... simply for overall "brain boosting."

Here is a recent look at using transcranial magnetic stimulation (TMS) for depression:

"This study provides new support for the efficacy of TMS (transcranial magnetic stimulation) as a 'stand alone' treatment for depression," said John Krystal, editor of Biological Psychiatry which will publish the study on December 1.

"This finding could be particularly important for patients who do not tolerate antidepressant medications, for whom they are not safe, or who have not benefited from other alternative treatments."

The treatment works by sending very rapid bursts of magnetic energy into the brain through coils attached to the scalp.

These pulses cause the neurons in a small area of the brain to "fire off," said study co-author Philip Janicak, a psychiatry professor at Rush University Medical Center in Chicago.

.... This is the first large-scale study of the technique and researchers also used much higher doses of the energy pulses.

Remission rates among those who received the treatment were twice as high as those receiving a "sham" treatment where a shield was placed on the coils.

They were also higher than average rates in antidepressant drug trials, Janicak said.

This is particular significant given that most of the patients in the study had failed to respond to antidepressants - a criteria which would have excluded them from most drug trials, he said.

Researchers in at 23 sites in Canada, the United States and Australian randomly assigned 325 patients suffering from major depressive disorder to nine weeks of magnetic stimulation or a sham treatment.

Physorg

We are a long way from understanding the complex structure and function of the human brain, and how it shapes our behaviour and conscious experience. Better methods of mapping microscopic nerve pathways in the brain should help, as should better real-time brain imaging techniques used in conjunction with targeted neuropsychological testing.

Using TMS, deep brain stimulation (DBS), neural interface chips, and other non-pharmacological methods of targeted modifying of brain pathways and nuclei should give researchers and clinicians more options for study and treatment of normal and pathological brain/mind processes.

Prime Time: When Your Unconscious is Thinking You

Unconscious priming--or subliminal priming--is a fascinating topic of cognitive science that is receiving more attention lately.

In a study that appeared in the journal Science in May, a team of English and French neuroscientists performed brain imaging on 18 men and women who were playing a computer game for money. The players held a handgrip and were told that the tighter they squeezed when an image of money flashed on the screen, the more of the loot they could keep.

As expected, the players squeezed harder when the image of a British pound flashed by than when the image of a penny did — regardless of whether they consciously perceived the pictures, many of which flew by subliminally. But the circuits activated in their brains were similar as well: an area called the ventral pallidum was particularly active whenever the participants responded.

“This area is located in what used to be called the reptilian brain, well below the conscious areas of the brain,” said the study’s senior author, Chris Frith, a professor in neuropsychology at University College London who wrote the book “Making Up The Mind: How the Brain Creates our Mental World.”

The results suggest a “bottom-up” decision-making process, in which the ventral pallidum is part of a circuit that first weighs the reward and decides, then interacts with the higher-level, conscious regions later, if at all, Dr. Frith said.

NYTimes

In "bottom-up" decision-making, subliminal cues "prime" the sub-conscious mind toward a particular response set. Curiously, the effect of sub-conscious priming can last for many years.

Black and white drawings were shown to people during an experiment in 1982. Seventeen years later, the same people (and some more used as a control) have been asked by mail to answer questions about drawings, some of them identical to the ones they had seen 17 years ago, and some different. The people who had participated in the first experiment were primed: they answered more easily to the questions related to the drawings they had seen 17 years ago, whereas the control participants showed no such difference. A funny thing is that some of the participants were unable to consciously remember the first study! They vaguely remembered having participated in psychology experiments, but nothing about this one in particular.Source

Some research has suggested that "priming God" may increase altruistic behaviour. An interesting discussion of this research can be found here.

Combining the bottom-up, subliminal decision making involved in "priming", with the long time duration of priming effects, and possible behavioural effects of "priming God," it is easy to see that many "character traits" of long term and habitual behaviours, might be influenced by early childhood "priming." In other words, decision making that you may feel reflects conscious higher-brain decision-making, may actually come from the lower reptilian brain unconscious--controlling-ghosts from the past.

Combatants in cultural and ideological wars are exquisitely aware of the "mental programming" effects of subliminal priming, and use various techniques in attempts to eradicate past programming to allow present and future programming. Certainly the modern academic lobotomy practised in most university liberal arts and social science programs--heavy slanting of the presentation in favour of one particular point of view, while preventing a balanced presentation of alternative POVs--suggests an attempt at eradicating old programming to clear the way for new programming. Other terms for this re-education process include "consciousness-raising" and "brainwashing."

Early childhood priming can be extremely powerful and long-lasting, resistant to most attempts to change. New methods of studying priming will inevitably be accompanied by new methods of changing "dysfunctional" priming. Crude psychiatric treatments such as electro-convulsive therapy persist in the treatment of intractable depression--even expand into treatment for other conditions such as schizophrenia--because they appear to get results. But less potentially damaging treatments such as targeted low-amplitude electromagnetic brain stimulation offer a more finessed approach to both research and treatment.

While pathologies such as PTSD, Panic, Phobias, etc. represent "priming effects," it is also likely that less well defined counter-productive behaviours that obstruct a person's happiness and success are also a result of priming.

Certainly the "hyper-judgmental" attitudes observed in assembled crowds (see almost any "Oprah" or similar show), reflect a more ominous phenomenon seen in "lynch mobs." The public physical and verbal attacks made on E.O. Wilson, and other intellectual messengers bringing unpopular and non-PC messages reveal similar dysfunctional primings within the attackers. The same priming pathology is seen in violent abortion clinic attackers, muslim suicide bombers, and college professors who verbally assault and grade-discriminate against students who may diverge from the professor's particular prejudices.


It is not that some people are guilty of being influenced by priming prejudice while others are not. It is that some have never confronted their priming prejudices at all. They were indoctrinated, but never worked and fought their way through and beyond the indoctrination. Whether Islamist fanatics, eco-terrorists, clinic bombers, campus PC Thought Police, or members of seemingly benign ideological movements to "shape the minds" of entire generations toward more "correct" ideologies, these practitioners of censorship, destruction, and mental stunting are "true believers" who are still functioning on their subliminal priming, unexamined.

We have the popular mental image of the "zombie," stalking stiffly across the landscape, unconsciously seeking its targets. It is not such a stretch to overlay the zombie image onto the eager ideologue, seeking minds to program.

Automatic Learning--It Came to Me in a Dream

Jeff Lieberman had a dream about ways of learning skillful physical movements without verbal coaching--pure tactile feedback. He went on to help develop a "haptics feedback suit" to study tactile learning. It is an intriguing idea.

MIT researchers Jeff Lieberman and Cynthia Breazeal have published the results of the study in a recent issue of IEEE Transactions on Robotics. The study presents a proof-of-concept wearable robotic system that provides real-time tactile feedback over every joint simultaneously.

“Oddly enough, the idea for the robot suit initially came from a dream,” Lieberman told PhysOrg.com. “The dream involved people who weren't physically able to express themselves, but who were mentally normal, who used a machine that aided them to get their inner feelings out. This ranged from people with muscular difficulties to even toddlers and 'untrained' people who do not know how to wield a paintbrush. Upon waking and thinking about that idea for about an hour, the idea for this project was born, and I started doing research that day; the overall project was about six months for software and hardware development.”

In experiments with arm motions, the researchers found that the suit increased students’ learning rates by up to 23%, and reduced errors by up to 27%, as well as enabling students to learn movements “more deeply” by affecting their subconscious learning of motor skills. The latter can be especially important for patients with neurological injuries who have lost the ability to form new long-term memories, but can still build new motor skills.

The suit works by optically tracking body markers for the teacher’s movement (or a pre-recorded ideal movement) and the student’s movement with a Vicon motion capture system, which has millimeter accuracy. The tracking data is fed to software that compares the teacher’s and student’s movements, and generates feedback signals to the suit.

Physorg

Imaginative persons can easily think of many uses for such a tactile feedback learning system. A large part of the widespread incompetence in society comes from the lack of practical skills with the hands and body. A sedentary society--forced to sit inactive for one third of the day from childhood to young adulthood, spending countless hours sitting watching television, texting, chatting, playing video games, etc--learns inactivity early, and neglects the body and the skills the body is capable of exhibiting.

The part of the mind that deals with banal, everyday things, or with abstract ideas, is well exercised by most children, teenagers, and adults. The parts of the mind that guide the body in skilled activities that make life more enjoyable, more workable, or more prosperous, are generally neglected.

Traditionally, fathers taught sons physical/tactile skills, as mothers taught tactile skills to daughters. Modern parents often do not have the time or spend the time to teach children practical skills. Such teaching requires patience and energy that may be lacking--not to mention the required skills that parents may never have been taught themselves. Now, these skills can be taught from tutorials online or on disk.

But the learning opportunities from such tactile feedback suits extends far beyond practical skills of modern life's technologies. Surgeons in training could learn from the deft, precise movements of the best surgeons. Pilots would learn firm, timely responses to unexpected emergencies in simulators.

It is one thing to teach the mind a skill. It is quite another to teach the body. Modern education neglects the body. (it also neglects the mind, but that is another story)

A deeper meaning behind such training is the fact that much of the cognitive strength of the mind derives from being "embodied." Our verbal and pre-verbal conceptual languages rest upon metaphors of embodiment. The sensory feedback from the body, as interpreted through embodiment metaphors, drives much of our thinking. More on this later.

The MIT research discussed in the Physorg article above promises important advances in a field of research that is not exactly brand new. But qualitative improvements in a pre-existing field can make the field seem new again.

Tactile feedback may just hold the conceptual key that has been missing from stonewalled efforts in machine intelligence, cognitive enhancement, and ultimately brain emulation and downloading. Stay tuned.

Re-Growing Damaged Brain

If humans are to live longer lives, we need ways to regenerate our brains from all sorts of neuronal damage. Adult brains can produce new neurons to replace some forms of brain damage. Maintaining brain function in extreme life extension is a matter of finding ways to expand this inherent ability of the brain.

Hat tip IConrad

Salamander Robots, Headless Chickens, Aimless People

Have you ever wondered how a chicken can continue to run around without its head? An animal's spinal cord is capable of much more control than most people realize. By understanding how the spinal cord controls rhythmic muscle movements, scientists are learning how to teach salamander robots to walk.

....choreographing robots designed to walk, swim, or run is a tougher task [ed.: compared to robots on wheels].

"Every time a foot hits or leaves the ground, the dynamics change," says Anthony Lewis, president of a company called Iguana Robotics in Illinois, US. "The standard methods that engineers use have a really hard time with this," because the calculations rapidly become very complex.

So some robotics researchers are starting to mimic biology. In animals, the mechanics of walking, swimming, running, and crawling are all coordinated by clusters of neurons in the spinal cord, called central pattern generators. These CPGs produce neural pulses that drive different muscles so that they contract rhythmically in a manner that produces running or walking motion, depending on the pattern of pulses.
Franken-salamander

This basic coordination does not require the brain, which is why a chicken can run around even after its head has been removed. However, simple signals from the brain can instruct the CPG to switch between different modes, from standing still to swimming or walking.

While roboticists would like to emulate this smooth transition between movements, biologists are starting to decipher the way it works. By removing most of a salamander's brain and stimulating the spinal cord with electricity, researchers have been able to make the amphibian's body wriggle as though swimming. If they decrease the intensity of pulsing slightly, the animal suddenly transitions to a walking motion.

Source

The salamander robot's "spinal cord" is just a hardware mimic of the biological salamander's spinal cord.

Central pattern generators control much of our day to day activity: walking, running, scratching, breathing . . . This activity takes place below the level of consciousness--although we can consciously switch from one pattern to another.

A trained athlete, dancer, or musician will spend years developing central pattern generators with exquisite precision, and superb responsiveness to higher control and feedback. Larry Bird, Magic Johnson, and Michael Jordan did not suddenly wake up one day and discover that they could play basketball. Tiger Woods was not born with his superb control of a golf club. Roger Federer did not become the undisputed best in the world at tennis by being a couch potato.

More intriguing to me are the central pattern generators that are not involved in motor control, but are rather involved in associative cognitive function. These are habits of mind, strange attractors of thought--conscious and subconscious. This is automaticity--the cortical counter-point to spinal pattern generators.

If the pattern generators of the brain and the spinal cord are superbly and intelligently trained over the years, people can accomplish incredible feats.

First of all, these generators have to be prompted at the appropriate times--the critical periods of development. Without the prompting, the child will never develop the motor skills, language skills, mathematical skills, and general cognitive skills that are needed in the modern technological world. That is a waste of human talent which is unfortunately widespread, both in the developed and undeveloped worlds.