Differential EEG

Doktor DynaSoar targeting at OMCL.mil
Thu Mar 4 22:16:01 EST 2004


I'm trimming some of the text. Don;t worry, the original remains on
file in Google Groups.

On Thu, 04 Mar 2004 04:06:44 GMT, "kpaulc"
<kpaulc at removeearthlink.net> wrote:

} This is an incomplete "draft" that I'd
} saved before Windows came to a
} full-"stop", and I had to reboot.
} 
} I'll follow-up if I can.
} 
} K. P. Collins
} 
} "Doktor DynaSoar" <targeting at OMCL.mil> wrote in message
} news:q5pc40d2nbkmmopth3r235rqt0hv6jmkbg at 4ax.com...
} > On Wed, 03 Mar 2004 19:57:49 GMT, "kpaulc" <kpaulc at earthlink.net>
} > wrote:
} >

} I'd use at least 3 simultaneous sets.
} 
} It's called "Triangulation".
} 
} The difference between SDEEG and what
} you've discussed is that the 'differentials'
} are all cross-correlated with respect to
} the same 'time' [you like 'time' :-].
...
} [What's the difference between what you're
} discussing and what I'm discussing?

Nothing yet.

} One can cross-correlate between x elec-
} trodes in one set of electrodes, no?
} 
} Yup.
} 
} But one gets only one set of 'ramps' [ampli-
} tude and frequency-summation gradients].
} 
} One can permute, using a varied subset of
} electrodes, but it's all just the =same= set of
} 'ramps' ['differentials'].
} 
} What's the difference in using three independ-
} ent sets of electrodes?
} 
} It gives three independent sets of 'ramps'.
.....
} The one thing is the 3-D-continuity.

Estimation of current source density, and so source dipole, using 3 or
more electrodes is typically done using Laplacian. I used 10 groups of
7 electrodes an ADHD study.

} The only thing I'm not sure of is, as I dis-
} cussed in my prior post, whether the sens-
} itivity of the recording electrodes is sufficient
} to 'see' the entirety of the brain's 3-D depth
} [and that's an Engineering Problem].

3-D source reconstruction software typically does a fine job of
locating subcortical sources. We get good agreement with fMRI
localization when we do simultaneous recording.




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