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New Imaging Technique Helps Explain Unconsciousness
smitty777 writes "A new imaging technique called fEITER (for functional Electrical Impedance Tomography by Evoked Response) attempts to explain the process of slipping into unconsciousness. The fEITER is a portable device that creates 3D imagery based on evoked potentials measured hundreds of times a second. The interesting finding from these studies is that unconsciousness appears to result from a buildup of inhibitor neurons. From the article: 'Our findings suggest that unconsciousness may be the increase of inhibitory assemblies across the brain's cortex. These findings lend support to Greenfield's hypothesis of neural assemblies forming consciousness.'"
Seems like Slashdot is unconcious today.
The spatial resolution of any scalp-based recording device is insufficient to say anything very informative about consciousness or assemblies, which were proposed by Donald Hebb in the 1940's to be the basis of information processing in the brain. We know much more about this process from animal models in which allow for recording the activity of neurons during sleep/wake/problem solving.
“We have been able to see a real time loss of consciousness in anatomically distinct regions of the brain for the first time. We are currently working on trying to interpret the changes that we have observed, as we still do not know exactly what happens within the brain as unconsciousness occurs, but this is another step in the direction of understanding the brain and its functions.”
FTFA:
The machine itself is a portable, light-weight monitor, which can fit on a small trolley. It has 32 electrodes that are fitted around the patient’s head. A small, high-frequency electric current (too small to be felt or have any effect) is passed between two of the electrodes, and the voltages between other pairs of electrodes are measured in a process that takes less than one-thousandth of a second.
While we're still a long way away from a practical direct neural interface, this certainly looks like a step in the right direction. They've demonstrated that the measurements are possible, and at a sample rate that is useful. Certainly there's room for improvement in sensitivity, sample rate, and resolution as well as in miniaturization.
When they can reduce this from a trolleycart -sized instrument to something one can support on one's head, then we'll see some more practical and less academic applications. (Yes, like porn. And games. And real virtual reality control of UAVs and waldoes.) Keep in mind that in the 80's, realtime Heads-Up Displays were this large and cumbersome... now look at them.
It really is illuminating to see how little we know about the nature of consciousness and thought, and how far away we still are from technologically-aided introspection.
I can see the fnords!
"Method to increase of inhibitory assemblies across the brain's cortex using an imaging technique"
aka 'C-SPAN'
Set your phasers on "funky"!
In the first Knights of the Old Republic game, there was an implant item whose flavor text read that it kept over-stimulation from overloading sensory brain parts, and causing damage or unconsciousness. This would be great for soldiers getting hit with IEDs, or whatnot.
I would be interested to know what constitutes a "neural assembly". I suspect than some form of coherence is involved. The question is whether or not this would be quantum coherence. This would be very difficult to establish of course, just as it was to establish quantum coherence in photosynthesis.
This is absurd. For a start, we don't have clue one about how to explain consciousness. Secondly, recording physical correlates to unconsciousness is not an explanation. Like so much of this stuff, it is description masquerading as explanation. Not bad as a start, perhaps, but don't call it "explanation".
Portable. Can tell what the brain is doing (i.e. either remembering or creating). Nah, no one would ever use it for that...
I'm having trouble seeing what's so exciting about explaining unconsciousness. Explaining consciousness would be exciting. I realize understanding what makes a person unconscious might help to understand what makes a person conscious. But not in this case. If they're just saying the presence of these inhibitors makes a person unconscious, then we're no closer to understanding consciousness. Because you can't just make an unconscious object become conscious by taking away these inhibitors. And you have no insight into bringing consciousness to something that never had it, regardless of whether these inhibitors were present. Maybe it could somehow help find a treatment for comas or something. Maybe those people are overloaded with these inhibitors. I don't know.
A Breathalyzer explains it just as well.
Have gnu, will travel.
You're upset that the researchers don't also assume that consciousness is some other kind of thing beyond material investigation. The researchers have no need for that assumption unless and until the evidence leads them there.
Interesting that consciouness is suppressed by inhibitory neurons- So consciousness is supressed by the brain, not expressed?
I beg to differ greatly with your assumption that "we don't have clue one about how to explain consciousness".
In fact we do know a few things...
You are never "conscious" all the time.
Every millisecond or so people are unconscious.
When you sleep you are also unconscious.
There can be many health related problems that would lead you to being unconscious.
Conscious machine properties:
Has minimums related to spacial volume, and computational capacity for human level "consciousness".
Has sensory input.
Processes sensory input.
Must have a set time-slice unit for processing new information (you will be unconscious during processing).
Reduces and stores important processed sensory information (must have memory).
Compares current sensory input with previous sensory input (negative and positive feedback).
Can generate associative differential information based on the comparison of current to previous information (and stores that for future feedback).
Can make decisions based on meta level associative differential information.
Can interact with its surroundings based on decisions.
Can process events over time, therefore reasoning that events occur over time.
Requires a semi-stable, but not quiescent, environment from which to operate in.
(Both environmental deprivation, and complete randomness for input would lead to a non-functioning machine.)
Probably requires extended downtime to further process daily high level associative differential (and hash) information for higher level reasoning. (Sleep)
Requires information loss. Must necessarily "forget" non-important (useless) information. It is impossible to store every sensory event.
Time slice processing can increase or decrease rate based on emergency life protection need.
(If your life is in danger, adrenaline will increase the rate of processing, and events will seem to "slow down".)
(Consequently when you age, your sensory processing rate naturally slows, so events in your life seem to "go by faster".)
So the machine must have memory for consciousness, otherwise it is just pure sensory "awareness" without knowledge of itself within and apart from the world.
You are a biochemical machine. All humans are biochemical machines which are "self aware" because of the above properties.
Based on the above properties, it should be possible to build an analog amplifier (op amp) that is trainable to obtain the voltage outputs we desire based on the discrete voltage level inputs. This amplifier would not necessarily be "conscious" but would be the core of something that one day could become "self-aware", and then to "consciousness".
Some philosophical wanderings...
Suppose you awoke the next morning in someone elses body with someone elses memory. Would you then not be "that" person?
The ultimate question is, what makes "you", you?
If you could make a complete copy of yourself using say, a Star Trek like transporter, then what would be the difference between you, and the other "you"? Only one thing... location, which is a position in space-time from which to have and generate separate associative differential information.
It is impossible to have two conscious beings occupy the same space-time location.
Is the "self aware" you that is "you" the same "self aware" me that is "me"? Coo coo ca choo.
%whoami
It looks like they tried to type "Feiter" as if they were normal people naming a thing, but they forgot their caps lock on.
3-D movie shows what happens in the brain as it loses consciousness...
http://www.youtube.com/watch?v=MzX7w2-FWAA (24 seconds)
So conciousness is like a critical section on multi threaded code? :)
I'm curious what the results of using this device to monitor REM sleep or meditation would produce.
first, you need a better grasp of ethology...
1,2, and 3, just no. simple explanation? to build. verb-- an action that ADDS data to 1,2.3 and other points you make, which are really just different words for the same thing...
4, 5, and 6 are tendencies, not a condition of. info is proc'd when awake, as you will see by reading this and learning. wait did I say learning? memory is a function of learning, NOT a prerequisite for consciousness, otherwise babies are not conscious, neither are amnesiacs... learning IS arguably a condition of consciousness... negative and positive is a very oversimplified idea, used in behaviouralsm--(skinner's work was more focused on ethology, even though many read psychology into his work and became frightened)
7,8, and 9, all defined by learning, meta is not applicable, since there is no limit to that loop, ie all meta data can be objectively analysed and new ideas can be drawn from this. interact with surroundings? see build and no need for sensory input examples (1-3)
10,11 and 12... time is not measured by our brain, nor are pixels seen in our vision, in spite of a ~4k x 4k celled retina. our brains fill in these gaps, just like + 20hz for sound. opposite of stable environment is needed, since it is made to proc changes. sense deprivation/or "white room", leads to "random data" ie hallucinations. not enough information to determine this as functionality or not.
13,14 and 15 are, while interesting, philosophical, not scientific. sleep is unknown at this time. 14 is an assumption on basic subconscious theory. 15 is not always true, a many animals sacrifice life to protect procreation, so self preservation is not an element of consciousness, but a product of it, or instinct.
even if all of those conditions you outlined were true, and you could create them satisfactorily in a machine-bio or otherwise, it would still not be conscious. objectivity, self awareness (very elusive)
learning, even more so, would not be there.
not that its a bad thing, but you already wandered philosophically. you are on the right track. a few things to remember. 1 given time learning is infinite. if there is no limit on resources, ie time, and matter, bio-mech needed to learn, then we can't see a limit on learning either..
instant copy of self is a good concept. the difference is existential, ie at that instance, it's a a spacetime reference, coupled with a different physical makeup, 1 because all matter even if it is infinite is unique, and 2 physiological development will be different instantly, as well as mental ie different data, stream of consciousness etc..
spacetime location s a very fuzzy thing, time implies relative velocity, and given this is subject to uncertainty principle. we have not yet defined consciousness as matter or energy, so there is not enough data to say if it can or cannot occupy any space at all. simple example? we don't shrink or lose weight when we die, but our body does stop expressing consciousness to outside observers...
also conjoined twins at the head/brain could lead to some interesting observations about consciousness, ie overlapping, occupying space, shared memory, thoughts/learning etc.. none have survived to offer any learning into the matter
How does fEITER compare with EEG/MEG tomography in spatial and temporal resolution? It seems to me (disclaimer IINANS) these latter methods can more or less measure the same phenomena that fEITER can. Morover, EEG/MEG tomography are truly passive/non-invasivve, while fEITER involves passing a high-frequency current thru the brain, which may affect the phenomenon itself thats being measured.
What am I missing? Can a neuroimaging expert here please explain the relative strengths and weaknesses of EEG/MEG tomography vs. fEITER?
Thanks
Joyous Blur Jockey