ELECTRIC ECHO: Sometimes, the brain appears to cheer on its own coordinated electric signaling.
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The rhythmic electric fields generated by the brain during deep sleep and other periods of intensely coordinated neural activity could amplify and synchronize actions along the same neural networks that initially created those fields, according to a new study. The finding indicates that the brain's electric fields are not just passive by-products of neural activity—they might provide feedback that regulates how the brain functions, especially during deep, or slow-wave, sleep. Although similar ideas have been considered for decades, this is the first direct evidence that the electric fields generated by the cerebral cortex change the behavior of the neurons that engender them.
"I think this is a very exciting new discovery," says Ole Paulsen, a neuroscientist at the University of Cambridge who was not involved in the recent study. "We knew that weak electric fields can impact brain activity, but what no one had really tested before was whether electric fields produced by the brain itself can influence its own activity."
The brain is an intricate network of individual nerve cells, or neurons, that use electrical and chemical signals to communicate with one another. Every time an electrical impulse, or action potential, races down the branch of a neuron, a tiny electric field surrounds that cell. "A few neurons are like individuals talking to each other and having small conversations," explains David McCormick, a neurobiologist at Yale University and co-author of the study published online July 15 in Neuron. "But when they all fire in unison, it's like the roar of a crowd at a sports game." That "roar" is the summation of all the tiny electric fields created by organized neural activity in the brain—it's what scientists record using electroencephalography (EEG), when they place a net of electrodes on a person's scalp.
"The question going into the study," McCormick says, "was whether electric fields generated by synchronous activity in the brain were passive consequences of that neural activity or somehow actively involved in regulating that activity." Investigating this question in the brain of a living animal would be ideal, but raises both ethical dilemmas and experimental difficulties because researchers need to do more than just record electrical activity in the brain—they need to manipulate it.
Instead, McCormick and colleagues created an experimental model that mimicked what might happen in the intact brain of a living animal. First, the researchers suspended a slice of brain tissue from the visual cortex of a ferret in artificial cerebrospinal fluid. The living cortical tissue behaved as though the ferret brain were in slow-wave (non–rapid eye movement), sleep, during which the brain produces sluggish but highly synchronous waves of electrical activity. The team's next step was to find out what would happen to the neural activity in the brain slice when it was subjected to a weak electric field.
They surrounded the cortical sample with an electric field that approximated the size and polarity of the fields produced by an intact ferret brain during slow-wave sleep to create an exaggerated version of the exact feedback loop they were investigating. Essentially, they enveloped the brain slice in an echo of itself.
When the team applied this electric field echo, they found it amplified and synchronized the neural activity in the brain slice. The field didn't create disorder—it increased harmony. The "roar" of the brain slice became louder and more regular. "It’s kind of like if you were cheering at a football game and someone played over the speaker the sound of the crowd cheering and you started responding to that, too, cheering along with both the real crowd and the speaker playback," McCormick explains. "It's a kind of reinforcing feedback."
Not only did the researchers show that this positive feedback facilitated the synchronous slow waves of electrical activity in the slice of ferret brain, they also showed that an electric field of the same strength, but opposite polarity, disrupted its synchronous neural activity. In other words, they showed that they could break the amplifying feedback loop with negative feedback. "Adding a positive feedback loop on top of what the slice produces itself increased synchronization," Paulsen explains, "but the clever bit was to demonstrate that negative feedback reduces synchronization. To me, it's the negative feedback experiment that is important here, and that really demonstrates that the endogenous [internally generated] fields are contributing to the synchronization."
The new study faces a couple methodological imperfections: First, the simple and uniform electric field created by electrodes in the laboratory does not perfectly mimic the complexity of electric fields generated by a living brain. Second, the experimental model relied on an incredibly thin slice of neural tissue—hardly the same as an intact brain. Paulsen says these flaws are unlikely to change the general conclusions of the study, however, because the underlying mechanisms of electrical activity remain consistent enough between the lab model and a living organism.
Because the brain produces especially large electric fields during highly synchronized neural activity, like that of slow-wave sleep, the researchers suspect the feedback loop they discovered could coordinate such phases of deep sleep—which are thought to bolster memory consolidation. "During slow-wave sleep, all your neurons march in order. The whole cortex takes part in this activity and the electric field feedback might help keep the neurons synchronized," McCormick says. "I think this is really going to change how people view the brain's electric fields."
Right now, though, researchers can only speculate as to the exact role of this feedback loop in everyday brain function, says Joseph Francis, a physiologist at the State University of New York Downstate Medical Center who has studied similar feedback in the hippocampus of a rat. "Originally, when I was doing my thesis work, what I wanted to know was whether one part of the brain could interact with another without physical contact," Francis explains. "What this new study shows is that it's possible for electric fields to have an influence on the neural activity itself without direct contact. But now we need to determine how much it has to do with normal functioning."
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Add CommentIt's time has come. I've been arguing this for years, but the scientists and computational technologists here in the San Francisco bay area have always resisted this hypothesis. I speculate that this resistance is due to the fact that such an assertion - namely, the parts both mold and are simultaneously molded by their collective activity - does not jibe with our Western culture's centuries old functional model based on closed systems. Essentially, the above study directly illustrates that closed loop systems are not sufficient in of themselves to manifest self-organization. This should be no surprise since all matter interacts in a superimposed topography of their mutually interacting physical forces; e.g. three body problem.
Reply | Report Abuse | Link to thisThis is not mysterious or radical science. It is the only logical way to account for negative entropy in living systems. But, as the three body problem (or n-body problem in the case of nature in general) attests, our traditional functional analysis (e.g. numerical analysis) struggle to accurately model such systems. Never the less, our culture has held on to such models jealously as the only legitimate approach to understanding open systems, because they are "knowable". Open systems such as the brain and biosphere aren't knowable like an arbitrarily closed system is knowable. Bertalanffy in his seminal book 'General System Theory' made this case in the '60s. It's time to really move the study of general open systems forward. This study is a welcome start.
For my personal contributions to this efforts see:
http://iforam.org/vision
Cheers,
Augustus
I would think an interesting experiment to follow this would be to see if you could cascade physically separate slices such that inducing feedback in one would cause it's field to induce the same field in the other (the second slice not being within the effective field of the electrode).
Reply | Report Abuse | Link to thisIf this worked, perhaps another experiment could follow such that the second slice is actually a living, "sleeping" test subject. This could be a two way experiment to measure both feedback induction and transmission.
=tell me does all this lead to my belief in TelePathy........brain to brain thought waves..........? I have witnessed a sure demo, and i have myself transmitted just once a very short message over a short distance within the house. Take your time, practice, and Try, your selves .
Reply | Report Abuse | Link to thisThe question to be asked (and is not being seen) is "what does this tell us of the physical reality that we live in?" Why do we assume that what we perceive with our senses is all that there is to perceive? No, I am not espousing metaphysics or religion. Perhaps like a fish, we exist in a stream and are not aware that we move in a limited space the boundaries of which we are not aware and that affect our movement through space and time - and that affect our behavior. "What a coincidence!" we hear often. If unexpected things which surprise us happen often, ought we be surprised anymore? Why is this kind of brain activity assumed to be "feedback"?
Reply | Report Abuse | Link to thisAnother interesting experiment: use a living human.
Reply | Report Abuse | Link to thisHuman brains are surrounded by small electric fields all the time. (Perhaps sleeping next to your cell phone is not the best!)
Surround 'the cortical sample with an electric field that approximate[s] the size and polarity of the fields produced by [a living human] brain during slow-wave sleep to create an exaggerated version of the exact feedback loop'.
Depression and anxiety disorders are associated with lighter sleep, more REM, and early wakefulness. By 'deepening' the sleep cycle using such an electrical field echo it may be possible to eliminate some of the symptoms of depression and anxiety disorders.
Squish, you are talking about neurofeedback, a way to non-invasively bring dysregulated brain waves back into regulated, synchronous activity. This directly impacts human mental states and stress responses as we self-regulate our brains through feedback to operate more effectively and efficiently.
Reply | Report Abuse | Link to thisThe results of this study make sense in that nearby electric fields should influence membrane potentials and excitability. The big question though is whether this is biologically significant or just constitutes a kind of noise, after all in an intact brain there must be a dynamic cacaphony of transient electric fields going on at nearly every point. This research suggests that vectors of electrical fields that might emerge from such noise could be biologically significant. If it is, since electric fields are also affected by magnetic fields it should be possible to see some kind of gross effect in your own head and consequent consciousness by placing an ordinary magnet near it or certainly by sticking your head into an MRI unit. I'm not talking about transcranial stimulation pulsed intensities that induce such strong local currents as to cause membrane depolarizations but weaker static magnetic fields that ought to still have some effect upon brain electric fields, and we don't see any noticeable effects, suggesting weak changes in local electic fields are not likely to be important in normal brain functioning. It would make sense from a systems approach too that such electrical noise ought to be filtered out, if anything, from acting upon the normal functioning of membrane excitability. However it would not surprise me to see very local effects in bundles of parallel fibers where their spacings, electrical conductivities, and membrane proteins were optimized to take advantage of multiple parallel firings so as to promote synchrony, shape the bundle waveforms, and perhaps influence things like axonal transport and other aspects of metabolism too. This is very interesting research and I think the next experiment should measure the effects upon two adjacent but surgically isolated noncommunicating axonal fibers; tease the ends apart, pulse stimulate both at one end and measure the action potential arrival times and intensities at the other ends, vary the pulse phase of one to see if any constructive or destructive interference can be produced in the second.
Reply | Report Abuse | Link to this@ DancesWithFascists: Based on you interesting points above you may find the following references useful:
Reply | Report Abuse | Link to thishttp://iofam.net/media/select-references
Local Field Potential (LFP), the electromagnetic field produced by local ensembles of neurons, has been shown to significantly alter spike activity. LFP has also been shown to be a better predictor than neuronal spike activity for localized blood response (i.e. the BOLD response).
I am not a scientist nor have I the education to provide the math to prove my theory, however I do have ideas to search for the proof. I believe that should this theory prove true, it will answer many questions we have about the universe around us; not just the grand reaches of space, but also the invisible micro world right before our eyes. So here is my theory:
Reply | Report Abuse | Link to thisUsing particle duality, consider the electromagnetic particle created by a neuron. It contains information that travels from point A to points B, C, etc.; within the brain. The electromagnetic waves that are emitted from brain activity produce a sea of light and sound around us and any living organism that produces or consumes energy. Each information particle produced in the brain by the sparking of a neuron carries a wave that connects a ‘doppelganger’ particle outside the brain. The swarm of particle activity inside the brain is copied and tethered outside the brain and swirls in the light and sound we produce. Because our brains do not produce high energy, the wave lengths are too low to be detectable by our own senses.
The light and sound is like a personal bubble that resonates at a certain frequency that corresponds to our mood and intensity of brain activity. When two people's ‘bubbles’ intermingle, the information particles swirling in the sea of light and sound have an opportunity to exchange or transfer information from person to person. If the polarity and frequency is compatible, the exchange and/or transfer take place. A personal quantum signature tags every electromagnetic particle created by our brains. This tag stays with the particle no matter where it goes. I believe that these particles containing information can also be sent to a specific location; an intentional transfer, especially if the sender is familiar with the quantum signature of the receiver, such as a twin. These particles can go from person to person to flower to rabbit to person,.. basically riding the light and sound waves of living things to arrive at its destination. The particle would find suitable polarities and frequencies to propel itself along the waves.
EEG's can record the brain waves that can be transferred to sound through a little creativity and some background in music and sound. Work is being done on that right now by a hand full of people, however they are either missing the science or the music background to get anywhere. Aura photography has captured the light waves emitted by our brains, but the resolution has not gotten to the point of seeing the particles within the light. A slow motion camera has been used to see the firing neurons inside the brain to the tune of 1 million frames a second. Although, I have seen; with relaxed eyes and a focus close to my face, these particles moving around. It is always only seen against a baby blue sky background. They look like small balls of energy riding along invisible pathways; like that of a network of neurons. The number of particles and the speed are always dependent on how deep in thought I am.
I think that if we can fine tune and connect these detecting devices, we should be able to view and hear the sights and sounds of our consciousness. We would then realize that we are connected to all living things and are in a sense all the same, only quantifyingly different. We may also find this micro process to be the case for larger things in the universe.
Thank you for the opportunity to share my theory with you. I look forward to your comments.
@tulcak
Reply | Report Abuse | Link to this..add this part to my last theory. Thought it might get your attention.
In theory, these duality particles can side-step dimensions. I believe that it is possible to be consciously aware of that dimensional travel during the dream state. We (our consciousness in the particle) could ride the particle wave to the ‘doppelganger particle' in our doppelganger in another dimension. The quantum signature might have enough similarities to be a compatible receptor for our request for informational transfer. We would experience their lives from their perspective through our telescope lens - our neuron sparked particle containing information; our consciousness. We would be tethered by the particle wave during the experience. If the second particle lands in the unconscious of our doppelganger, then we would only be a spectator to what they do. But, if the particle lands in the conscious of our doppelganger, then we can influence what their actions are. I believe that free will exists and can be influenced by others or ourselves even by simple proximity.