These results were most likely not due to experimental artifact. Here is why:
They were recording extracellularly from neurons, through extremely fine tipped (5 microns or so),
microelectrodes, not doing EEG. EEG is sticking
electrodes on the outside of the head and
recording the population response of thousands of neurons at once. With microelectrodes, on the other hand, you can record from a single neuron.
This is why these neurons were not found 100 years ago with EEG -- it is not possible to record from single neurons with them. People have only been able to record from single neurons
for about 50 years. These experiments are recording *in the alive, awake, monkey*, further complicating matters. Techniques allowing single unit recordings in awake monkeys have not been around very long, and so there is a wealth of neuron responses simply not characterized. For
instance, there was a sensationalized paper out a few weeks ago in science about "dog" and "cat" cells which were just found.
What you said, about possibly picking up local currents, is true in that when recording extracellularly, you are going to get background 'noise' from other cells in the population. This is easily dealt with, however, with various methods. The action potentials in neurons have a constant amplitude, and so you can just listen to the neuron firing with the largest amplitude, and hence closest to the microelectode. If you want to get fancy, you can put a few electrodes in a bundle and cancel out the background noise by substracting what is recorded in the different electrodes. Experimental artifacts of these sorts are not really a problem, anymore.
Something neat, however, was that these cells were initially found by accident. They were searching for something else, and happened to notice cells were firing both when the monkey picked up a raisin and when the experimenter picked it up. Ahh, science.
Now the article, and that essay about these cells being the key to human evolution and language and all of that.. now that I think is total crap. hehe.
Sometimes I wonder if using the attack actually makes things worse by the following mechanism in addition to the above selection: Presumably, a variant organism and a "standard" organism compete for resources in an environment. Thus the standard
organism keeps resources from the variant that it would otherwise have. So the standard organism actaully inhibits the spread of the variant (not to mention providing something for immune systems to cut their teeth on). Remove the standard organism, and the stronger variant has less competition....
That does not make any sense in that if you
were attempting to kill an organism in the
first place, you don't care whether or not
it is resistant to a form of attack or not,
you just want it gone. The "standard organism"
is just as much of a problem as the "variant",
so it doesn't matter whether or not there is
selection pressure for the variants to win out.
If you just let all of the organisms hang around
it would be the same result as letting the
variants take over the population. The person
would be dead or the water would be
contaminated or whatever.
It is -misuse- of a technique that is the problem.
This provides unnecessary selection pressure
towards the variant you can do nothing about, which is why there is a big stink about
overperscription of antibiotics and what have you.
There have been laser devices already fabricated to remove arterial blockage, and they are not
any more successful than ballooning the blockage or what not. Every way the blockage is removed
there is trauma to the arteries themselves in
the form of heat damage with the laser or
mechanical damage from ballooning or
heat from drilling or damage from physically
positioning the device in the artery, etc.
The trauma causes scarring and a reclosing of the
artery, bringing about 20% of the patients
back to square one.
-rory
Slashdot Mirror
These results were most likely not due to experimental artifact. Here is why:
They were recording extracellularly from neurons, through extremely fine tipped (5 microns or so), microelectrodes, not doing EEG. EEG is sticking electrodes on the outside of the head and recording the population response of thousands of neurons at once. With microelectrodes, on the other hand, you can record from a single neuron. This is why these neurons were not found 100 years ago with EEG -- it is not possible to record from single neurons with them. People have only been able to record from single neurons for about 50 years. These experiments are recording *in the alive, awake, monkey*, further complicating matters. Techniques allowing single unit recordings in awake monkeys have not been around very long, and so there is a wealth of neuron responses simply not characterized. For instance, there was a sensationalized paper out a few weeks ago in science about "dog" and "cat" cells which were just found.
What you said, about possibly picking up local currents, is true in that when recording extracellularly, you are going to get background 'noise' from other cells in the population. This is easily dealt with, however, with various methods. The action potentials in neurons have a constant amplitude, and so you can just listen to the neuron firing with the largest amplitude, and hence closest to the microelectode. If you want to get fancy, you can put a few electrodes in a bundle and cancel out the background noise by substracting what is recorded in the different electrodes. Experimental artifacts of these sorts are not really a problem, anymore.
Something neat, however, was that these cells were initially found by accident. They were searching for something else, and happened to notice cells were firing both when the monkey picked up a raisin and when the experimenter picked it up. Ahh, science.
Now the article, and that essay about these cells being the key to human evolution and language and all of that.. now that I think is total crap. hehe.
-rory
It is -misuse- of a technique that is the problem. This provides unnecessary selection pressure towards the variant you can do nothing about, which is why there is a big stink about overperscription of antibiotics and what have you.
There have been laser devices already fabricated to remove arterial blockage, and they are not any more successful than ballooning the blockage or what not. Every way the blockage is removed there is trauma to the arteries themselves in the form of heat damage with the laser or mechanical damage from ballooning or heat from drilling or damage from physically positioning the device in the artery, etc. The trauma causes scarring and a reclosing of the artery, bringing about 20% of the patients back to square one. -rory