[Eeglablist] Source localization and hippocanpus

[m za]

Hi Makoto ,
Thank you. No worries at all, and I really appreciate the clarification and
your thoughtful feedback. This distinction is very helpful for framing my
method appropriately.

On Wed, Aug 26, 2026 at 1:20 AM Makoto Miyakoshi via eeglablist <
eeglablist at sccn.ucsd.edu> wrote:

> Hi Marjan,
>
> Thank you for your explanation. Yes, I remember your implementation.
>
> I also recognize that this approach should not be described as anatomical
> source localization. A more precise description would be an
> electrode-informed regional representation of ICA components, and I will
> revise the manuscript accordingly.
>
>
> That is it.
> So my comment was probably missing the point for you, sorry about that.
>
> That said, as a general comment, which I believe is still noteworthy, is
> that I'm not saying that ICA + dipole fitting is wrong. As long as the
> result is treated as a model with unclear scale, that is fine. If it claims
> physiological validity, then the validity of the dipole moment must be
> examined.
>
>
> Makoto
>
>
> On Mon, Aug 24, 2026 at 1:08 PM m za <ma.zamani.20 at gmail.com> wrote:
>
> > Dear Makoto and colleagues,
> >
> > Thank you for the detailed critique. It helped me identify an important
> > distinction that I should make more explicitly.
> >
> > My current method does not estimate an IC dipole location, orientation,
> or
> > physical dipole moment, and it does not interpret ICA component weights
> in
> > absolute physical units. Instead, channel coordinates are first used to
> > define electrode-based regional groups. The scalp projection of each IC
> is
> > then summarized within these groups to obtain a relative regional weight
> > profile, which is thresholded and used to construct regional time-series
> > representations.
> >
> > Therefore, I agree that ICA scaling ambiguity would invalidate any
> attempt
> > to interpret these weights as physical dipole strength. That is not the
> > intended interpretation of my method. The resulting signals are used as
> > data-driven, electrode-informed regional representations for downstream
> > connectivity analysis, rather than as quantitatively localized or
> > physically calibrated sources.
> >
> > I also recognize that this approach should not be described as anatomical
> > source localization. A more precise description would be an
> > electrode-informed regional representation of ICA components, and I will
> > revise the manuscript accordingly.
> >
> > Thank you again for raising this issue. It has helped me clarify both the
> > scope and the limitations of the method.
> >
> > Best regards,
> > Marjan Zamani
> >
> > On Mon, Aug 24, 2026 at 9:17 AM Makoto Miyakoshi via eeglablist <
> > eeglablist at sccn.ucsd.edu> wrote:
> >
> >> Hi Yevgeny, Cedric, and Marjan,
> >>
> >> Thank you for your comments!
> >>
> >> I published the L-EEGibility Atlas on Github and Zenodo.
> >>
> >>
> https://urldefense.com/v3/__https://github.com/MakotoMiyakoshi/L-EEGibility-Atlas/tree/main__;!!Mih3wA!AF89gXQ_Bw1a_fYT3Lwj_tIHdNTuHFcI9VNexSVkbRNU_Eu6Hws2v5AeyUpAd909X_XItKDCYj7xKhNs_QtbXMho29w$
> >>
> >> I also submitted it to the EEGLAB plugin request.
> >>
> >> There was a bug in code, so the initially reported L hippocampal source
> >> contribution is updated from 1.649 to 2.009 microV.
> >>
> >> For Yevgeny,
> >>
> >> However, the conclusion regarding whether signals from the hippocampus
> can
> >> be recorded on the scalp relies on several assumptions, and these can be
> >> challenged. The first is that the source is necessarily a dipole.
> >>
> >>
> >> I do not understand this. An n-pole model is just a model. You choose
> >> which
> >> model to fit, not the brain uses it. Do I miss something?
> >>
> >> The second is that it is a single dipole, not a set of synchronized
> >> dipoles
> >> distributed over a certain area and similarly oriented.
> >>
> >>
> >> Typically, a single dipole model may be used because there is no
> monopole
> >> (current conservation) and rapid delay of > quadru-poles for scalp EEG
> >> recording. For intracranial invasive, things are different.
> >>
> >> 1. In addition to the dipole component, a monopole component also
> >> contributes to the EEG.
> >>
> >>
> >> Invasive brain recording may capture near-DC electrodiffusive
> >> neuron-extracellular-glia (edNEG) current, for example, between
> dendritic
> >> and somatic areas (Halnes et al, there are many of them). But this
> >> edNEG-caused potential field does not propagate. edNEG is a potential
> >> field, not a current source.
> >>
> >> Likewise, the potential from a system of quadrupoles can propagate over
> a
> >> greater distance than from a single dipole.
> >>
> >>
> >> I'm curious if this can really happen. It's certainly different from
> what
> >> I
> >> learned. I think the point is the word 'a system of quadrupoles' What
> >> system could it be, like an array formed?
> >>
> >> For Cedric,
> >>
> >>
> >> 1) why not including subiculum?
> >>
> >> I do not know why the subiculum is usually not counted as a part of the
> >> hippocampus proper.
> >>
> >>
> >> 2) is this only using dipole fitting tools? what about other methods
> like
> >> eLoreta or LCMV beamforming?
> >>
> >> No, it is not a dipole fitting tool. It's a leadfield model calculated
> >> from
> >> Colin27 + original hippocampus BEM model.
> >> The left hippocampus alone (CA1-4) has 5771 vertices.
> >>
> >>
> >> -> I'm surprised, I remember clearly the Colin atlas having the
> hippocampi
> >> included when using the ROIconnect plugin for LCMV beamforming, which I
> >> had
> >> to exclude in the code as I suspected it was not reliable, but it was
> >> there.
> >>
> >>
> >> This is from Destrieux et al. (2010): "Using this process, each vertex
> of
> >> the cortical surface was assigned to an anatomical label from the name
> >> database. On the midline an area labeled Medial_wall grouped structures
> >> not
> >> involved by the inflation process, including the hippocampus, thalamus,
> >> ventricles, and corpus callosum." I'm sure there are multiple
> >> Colin27-based
> >> atlases. The Destrieux Atlas does not have hippocampi.
> >>
> >> -> is a single subject head model the way to go for validating this kind
> >> of
> >> thing? aren't the findings vulnerable to be specific to this person
> only?
> >>
> >>
> >> Yes, otherwise you won't see clearly defined sulci. I wanted to evaluate
> >> cancellations of EEG signals due to cortical folding. The finding is
> >> biased
> >> to Dr. Colin's brain, yes, but an averaged brain does not have clearly
> >> defined sulci. The Destrieux Atlas comes with annotations for all gyri
> and
> >> sulci.
> >>
> >> For Marjan,
> >>
> >> My approach is bottom-up: starting from empirical scalp EEG, each ICA
> >> component is given a regional score based on its scalp-weight
> distribution
> >> and is assigned to an anatomical ROI if it meets the assignment
> criterion.
> >>
> >> IC is not a physical entity. It's just a model.
> >> An interesting question is, if ICs can ever touch the ground truth of
> EEG,
> >> how can it be verified?
> >>
> >>
> >> Your approach is top-down: starting from an assumed ROI-level source,
> the
> >> forward-projected scalp amplitude is evaluated against a detectability
> >> threshold.
> >>
> >> No, it is bottom up. It does not start from ROI-level sources, but BEM
> >> mesh
> >> vertices.
> >> The leadfield matrix of the L-EEGibility Atlas is 343 (ch) x 15002
> >> (vertices) for the original Destrieux Atlas, plus 343 (ch) x 9308
> >> (vertices) for hippocampi (I know these hippocampi are mapped too
> >> densely).
> >> So there are 24310 dipoles projecting to 343 scalp electrodes.
> >>
> >> One more interesting thing. Your ICA-based approach cannot maintain the
> >> meaning of the measurement unit (V).
> >> ICs are often associated with a single dipole model, but what does its
> >> dipole moment mean physically? Delorme et al. (2012) discussed 'residual
> >> variance' as a quantifier, but it is not a physical quantity! Unknown
> >> nature of IC-dipole moment has been the biggest weak point of the
> >> physiological interpretation of ICA (See also EFB p82-83 for the related
> >> criticism.)
> >>
> >> Makoto
> >>
> >> On Fri, Aug 21, 2026 at 8:50 PM m za <ma.zamani.20 at gmail.com> wrote:
> >>
> >> > Hi ,
> >> >
> >> >  Reading this, I noticed an interesting structural parallel with the
> >> > ROI-assignment step in the pipeline I shared last month, although the
> >> > direction and the scientific question are different. My approach is
> >> > bottom-up: starting from empirical scalp EEG, each ICA component is
> >> given a
> >> > regional score based on its scalp-weight distribution and is assigned
> >> to an
> >> > anatomical ROI if it meets the assignment criterion. Your approach is
> >> > top-down: starting from an assumed ROI-level source, the
> >> forward-projected
> >> > scalp amplitude is evaluated against a detectability threshold. So, in
> >> both
> >> > cases, a quantitatively defined regional measure is compared with a
> >> > criterion to support a decision, but the decision target differs—ROI
> >> > attribution in my pipeline versus scalp detectability in yours. I
> >> thought
> >> > that was a neat and potentially complementary parallel, but I would be
> >> > interested to hear whether you see it differently.
> >> >
> >> > Marjan Zamani
> >> >
> >> > On Sat, Aug 22, 2026 at 12:18 AM Cedric Cannard via eeglablist <
> >> > eeglablist at sccn.ucsd.edu> wrote:
> >> >
> >> >> Hi Makoto,
> >> >>
> >> >> Exciting development. Thanks for working on this, I've always thought
> >> it
> >> >> is a big gap in the EEG field to have such questions unanswered.
> >> >>
> >> >> Quick curiosity questions:
> >> >> 1) why not including subiculum?
> >> >> 2) is this only using dipole fitting tools? what about other methods
> >> like
> >> >> eLoreta or LCMV beamforming?
> >> >> 3) "Destrieux Atlas is based on Colin27, which is a single-subject
> head
> >> >> model and has annotated gyri and sulci. But it does not come with
> >> >> hippocampi. So I used HippUnfold (DeKraker et al., 2022, 2023) to
> >> >> auto-demarcate hippocampi on the Destrieux Atlas."
> >> >>
> >> >> -> I'm surprised, I remember clearly the Colin atlas having the
> >> >> hippocampi included when using the ROIconnect plugin for LCMV
> >> beamforming,
> >> >> which I had to exclude in the code as I suspected it was not
> reliable,
> >> but
> >> >> it was there.
> >> >>
> >> >> -> is a single subject head model the way to go for validating this
> >> kind
> >> >> of thing? aren't the findings vulnerable to be specific to this
> person
> >> only?
> >> >>
> >> >>
> >> >> Cedric
> >> >>
> >> >>
> >> >> Sent with Proton Mail secure email.
> >> >>
> >> >> On Friday, August 21st, 2026 at 1:00 PM, Cedric Cannard <
> >> >> ccannard at protonmail.com> wrote:
> >> >>
> >> >> > Hi Makoto,
> >> >> >
> >> >> > Exciting development. Thanks for working on this, I've always
> thought
> >> >> it is a big gap in the EEG field to have such questions unanswered.
> >> >> >
> >> >> > Quick curiosity questions:
> >> >> > 1) why not including subiculum?
> >> >> > 2) is this only using dipole fitting tools? what about other
> methods
> >> >> like eLoreta or LCMV beamforming?
> >> >> > 3) "Destrieux Atlas is based on Colin27, which is a single-subject
> >> head
> >> >> model and has annotated gyri and sulci. But it does not come with
> >> >> hippocampi. So I used HippUnfold (DeKraker et al., 2022, 2023) to
> >> >> auto-demarcate hippocampi on the Destrieux Atlas."
> >> >> >
> >> >> > -> I'm surprised, I remember clearly the Colin atlas having the
> >> >> hippocampi included when using the ROIconnect plugin for LCMV
> >> beamforming,
> >> >> which I had to exclude in the code as I suspected it was not
> reliable,
> >> but
> >> >> it was there.
> >> >> >
> >> >> > -> Are you sure using an automated method like HippUnfold is fully
> >> >> reliable?
> >> >> >
> >> >> > -> is a single subject head model the way to go for validating this
> >> >> kind of thing? aren't the findings vulnerable to be specific to this
> >> person
> >> >> only?
> >> >> >
> >> >> >
> >> >> > Cedric
> >> >> >
> >> >> >
> >> >> > Sent with Proton Mail secure email.
> >> >> >
> >> >> > On Friday, August 21st, 2026 at 10:48 AM, Евгений Машеров via
> >> >> eeglablist <eeglablist at sccn.ucsd.edu> wrote:
> >> >> >
> >> >> > > First of all, thank you very much for this fascinating and
> >> important
> >> >> work.
> >> >> > > The threshold for EEG amplitude that allows signal registration,
> >> 1.65
> >> >> μV, seems reasonable. By comparison, when diagnosing brain death, an
> >> >> amplitude of oscillations of 2-3 μV does not prove brain function and
> >> is
> >> >> considered an artifact.
> >> >> > > However, the conclusion regarding whether signals from the
> >> >> hippocampus can be recorded on the scalp relies on several
> >> assumptions, and
> >> >> these can be challenged. The first is that the source is necessarily
> a
> >> >> dipole. The second is that it is a single dipole, not a set of
> >> synchronized
> >> >> dipoles distributed over a certain area and similarly oriented.
> >> >> > > The question of the validity of these assumptions arose in my
> mind
> >> >> quite a while ago, when I was tasked with using the BrainLoc dipole
> >> >> localization program (developed by Yuri Koptelov) to analyze clinical
> >> EEGs.
> >> >> I was immediately skeptical about the possibility of recording a
> signal
> >> >> from a non-cortical dipole on the scalp, since the dipole potential
> >> >> decreases inversely with the square of the distance. However,
> practical
> >> >> experience has shown that sources deep in the brain are localized
> quite
> >> >> accurately, and their location is confirmed by recordings during
> >> surgery or
> >> >> from implanted electrodes.
> >> >> > > In an attempt to explain this paradox, I proposed two
> explanations.
> >> >> > > 1. In addition to the dipole component, a monopole component also
> >> >> contributes to the EEG. Its potential decreases less rapidly with
> >> distance
> >> >> and can therefore be recorded at a greater distance. A possible
> source
> >> of
> >> >> this component could be fluctuations in the ionic composition inside
> >> and
> >> >> outside the neuron (the contribution of glia may also be
> significant).
> >> >> > >
> >> >>
> >>
> https://urldefense.com/v3/__https://link.springer.com/article/10.1134/S0006350919030138__;!!Mih3wA!GQ6tkO0-y-UdiBpSSa5dvJ5WwALJ32XNjpXJS-5N7m99k4m-659LlesRaG8YmhUmYS88D71nxC6knyaGTmLBp4yz1xU$
> >> >> > >
> >> >> > > 2. The potential from a system of dipoles changes differently
> than
> >> >> from a single dipole and propagates over a greater distance.
> Likewise,
> >> the
> >> >> potential from a system of quadrupoles can propagate over a greater
> >> >> distance than from a single dipole.
> >> >> > >
> >> >>
> >>
> https://urldefense.com/v3/__https://link.springer.com/article/10.1134/S0006350921040114__;!!Mih3wA!GQ6tkO0-y-UdiBpSSa5dvJ5WwALJ32XNjpXJS-5N7m99k4m-659LlesRaG8YmhUmYS88D71nxC6knyaGTmLBvqm70Fw$
> >> >> > >
> >> >> > > It is quite possible that both of these mechanisms need to be
> taken
> >> >> into account, and even then the complexity of the EEG generation
> >> process
> >> >> may not be exhausted.
> >> >> > >
> >> >> > > Your truly
> >> >> > >
> >> >> > > Eugen Masherov
> >> >> > >
> >> >> > > > Hi list,
> >> >> > > >
> >> >> > > > Earlier this year, we discussed whether scalp EEG can measure
> >> >> > > > hippocampus. Komal
> >> >> > > > and I developed a forward model simulator, L-EEGiability Atlas,
> >> to
> >> >> answer
> >> >> > > > this question. The Github repository is still private. It'll be
> >> >> published
> >> >> > > > after Komal registers it to Zenodo. This is a follow up.
> >> Technical
> >> >> detail
> >> >> > > > of this forward model is provided after my signature.
> >> >> > > >
> >> >> > > > In this forward model simulation, the parameters uses are:
> >> >> > > >
> >> >> > > > Dipole moment: 0.17 nAm/mm^2 (which is the strength of sleep
> >> >> spindle)
> >> >> > > > Uniform recruitment rate: 66.6% (arbitrary choice, but for a
> >> >> specific
> >> >> > > > reason--you will find the reason below)
> >> >> > > > Selected regions: CA1, CA2, CA3, CA4 in the left hemisphere (no
> >> >> subiculum)
> >> >> > > > Total ROI area: 9.59 cm^2
> >> >> > > >
> >> >> > > > A critical fact is that EEG signals smaller than 1.65 microV
> are
> >> not
> >> >> > > > guaranteed to be measured (Nuwer et al., 1998). I guess this
> >> >> reflects
> >> >> > > > realistic requirements of an EEG recorder's noise floor. Thus,
> <
> >> >> 1.65
> >> >> > > > microV means 'not eligible for scalp EEG'.
> >> >> > > >
> >> >> > > > In this condition, the maximum scalp potential observed is
> 1.649
> >> >> microV!
> >> >> > > >
> >> >> > > > Thus, to measure hippocampal EEG, average dipole moment needs
> to
> >> be
> >> >> > 0.17
> >> >> > > > nAm/mm^2 and/or average recruitment rate needs to be > 66.6%.
> Our
> >> >> next
> >> >> > > > question is therefore: can we obtain empirical evidence
> >> supporting
> >> >> these
> >> >> > > > numbers?
> >> >> > > >
> >> >> > > > By the way, if the left hippocampus becomes epileptic (uniform
> >> >> recruitment
> >> >> > > > 100%, 0.77 nAm/mm^2), you would measure 11.126 microV at the
> >> scalp.
> >> >> If I
> >> >> > > > apply the Murakami-Okada limit of 2 nAm/mm^2, the measured
> signal
> >> >> would be
> >> >> > > > 19.402 microV.
> >> >> > > >
> >> >> > > > Here is the comparison table to get a feeling of how much depth
> >> and
> >> >> folding
> >> >> > > > penalty the hippocampus EEG undergoes
> >> >> > > > (all left hemisphere ROIs, 0.17 nAm/mm^2, uniform 66.6%
> >> recruitment,
> >> >> > > > amplitude shown is positive peak only at the scalp maximal,
> >> >> three-layer
> >> >> > > > BSCR=40 model)
> >> >> > > >
> >> >> > > > Hippocampus, 9.59 cm^2, 1.649 microV
> >> >> > > >
> >> >> > > > Sup Occipital Gyrus, 15.71 cm^2, 36.283 microV
> >> >> > > > Sup Parietal Gyrus, 34.94 cm^2, 42.330 microV
> >> >> > > > Postcentral Gyrus, 28.94 cm^2, 26.263 microV
> >> >> > > > Sup Temporal Gyrus, 24,17 cm^2, 24.420 microV
> >> >> > > > Inf Front Opercular, 19.75 cm^2, 18.194 microV
> >> >> > > >
> >> >> > > > Insula, 30.77 cm^2, 16.238 microV
> >> >> > > >
> >> >> > > > All pure Gyri, 784.19 cm^2, 49.404 microV
> >> >> > > > All pure Sulci, 338.03 cm^2, 48.325 microV
> >> >> > > >
> >> >> > > > Whole brain, 2348.56 cm^2, 29.956 microV
> >> >> > > >
> >> >> > > > Angular + Supramarginal + Sup Parietal + IntraParietal Sulcus,
> >> >> 113.42 cm^2,
> >> >> > > > 80.957 microV
> >> >> > > >
> >> >> > > > Note that the area of the selected ROI and the scalp-measured
> EEG
> >> >> amplitude
> >> >> > > > do not correlate. This is because (1) cancellations due to
> >> >> foldings, (2)
> >> >> > > > the effect of volume conduction is actually limited locally so
> >> that
> >> >> source
> >> >> > > > effects do not add up at one measurement point.
> >> >> > > >
> >> >> > > > If you have a request to test some hypothesis/question, let me
> >> know.
> >> >> > > > L-EEGiability will be publically available in a week or two.
> >> >> > > >
> >> >> > > > Makoto
> >> >> > > >
> >> >> > > > %%%%%%%%%%%%%%%%%%%%%%
> >> >> > > > Technical note
> >> >> > > >
> >> >> > > > Leadfield-based EEG eligibility (L-EEGiability, pronounced as
> >> >> > > > 'eligibility') Atlas is an extended version of the Destrieux
> >> Atlas
> >> >> > > > (Destrieux et al., 2011). Destrieux Atlas is based on Colin27,
> >> >> which is a
> >> >> > > > single-subject head model and has annotated gyri and sulci. But
> >> it
> >> >> does not
> >> >> > > > come with hippocampi. So I used HippUnfold (DeKraker et al.,
> >> 2022,
> >> >> 2023) to
> >> >> > > > auto-demarcate hippocampi on the Destrieux Atlas.
> >> >> > > >
> >> >> > > > Then I determined a physiological plausible range of current
> >> dipole
> >> >> moments
> >> >> > > > in nAm/mm^2 for the human brain (Murakami & Okada, 2015;
> Inverso
> >> et
> >> >> al.,
> >> >> > > > 2016; Rosen et al., 2019). The reported values are like 0.17
> for
> >> >> sleep
> >> >> > > > spindle, 0.2-0.35 for visual evoked potential at V1, and
> >> 0.16-0.77
> >> >> for
> >> >> > > > interictal spikes. Murakami & Okada also proposed a
> physiological
> >> >> limit of
> >> >> > > > 1-2 nAm/mm^2.
> >> >> > > >
> >> >> > > > I also set a few other open parameters, such as synchronization
> >> >> rate. This
> >> >> > > > is completely arbitrary. We need empirical data to fill this
> in.
> >> >> > > >
> >> >> > > > The brain-to-skull-conductivity (BSCR) ratio precalculated are
> >> 26,
> >> >> 40, 80.
> >> >> > > > Although BSCR=26 is the modern estimate, because the model is
> >> three
> >> >> tissue
> >> >> > > > layers without CSF, using BSCR=40 compensates for the lack of
> CSF
> >> >> layer
> >> >> > > > (EFB Chapter 6).
> >> >> > > >
> >> >> > > > On Fri, Jan 30, 2026 at 5:29 PM Makoto Miyakoshi <
> >> >> mmiyakoshi at ucsd.edu>
> >> >> > > > wrote:
> >> >> > > >
> >> >> > > >> Hi all,
> >> >> > > >>
> >> >> > > >> I've read this discussion with great interest!
> >> >> > > >> Here are my thoughts.
> >> >> > > >>
> >> >> > > >> 1. If I adopt a conventional dogma of generative mechanism of
> >> EEG
> >> >> > > >> i.e., all/most of scalp-measured EEG signals entirely
> generated
> >> by
> >> >> > > >> post-synaptic membrane potential in cortical surface (Electric
> >> >> Fields of
> >> >> > > >> the Brain, EFB, by Nunez and Srinivasan 2006 adopts this
> >> >> assumption, for
> >> >> > > >> example), measuring EEG signals generated in the hippocampus
> >> using
> >> >> a
> >> >> > > >> conventional EEG recorder (i.e., sensitivity limit > 1 microV)
> >> >> would be
> >> >> > > >> impossible primarily because of the geometry (too small, too
> >> deep,
> >> >> rolled
> >> >> > > >> shape, etc..)
> >> >> > > >> 2. However, a modern electrodiffusive
> neural-extracellular-glia
> >> >> > > >> (edNEG) model indicates the possibility that non-synaptic
> source
> >> >> activity
> >> >> > > >> affects scalp EEG as well, which is much less studied. See
> >> Saetra
> >> >> et al.
> >> >> > > >> (2021) for full details (but this one is super technical).
> >> >> > > >>
> >> >>
> >>
> https://urldefense.com/v3/__https://journals.plos.org/ploscompbiol/article?id=10.1371*journal.pcbi.1008143*libraryItemId=11397962__;LyM!!Mih3wA!BJz_jI7amVJIO4yLx16kUNcvtKfKz2Vq2a8fn-buH6yEmuldbNRSNq8JZ679B42teXAZ4sz3nMIKlNimhKtMlKPZmVs$
> >> >> > > >> 3. I read the dispute between Joseph's group and Mike's group
> >> with
> >> >> > > >> great interest. If I stand on the conventional viewpoint, I
> >> agree
> >> >> with
> >> >> > > >> Mike, and I usually stand on it. But that does not mean
> >> >> non-conventional
> >> >> > > >> source cannot exist, particularly if it is observed in a
> >> >> low-frequency
> >> >> > > >> range (below delta). After all, we do not know EEG phenomenon
> >> >> completely,
> >> >> > > >> so we are not there yet to make an a priori prediction that
> can
> >> >> properly
> >> >> > > >> bound the observation (i.e., "If we observe X under certain
> >> >> conditions, it
> >> >> > > >> MUST BE noise because it cannot be there from biophysics!")
> >> >> > > >> 4. That said, I still want to emphasize that learning the
> >> >> conventional
> >> >> > > >> synaptic dogma and EEG's unique scaling law (i.e., volume
> >> >> conductor theory,
> >> >> > > >> including what I call 'transducer array effect' of a dipole
> >> layer)
> >> >> is very
> >> >> > > >> important. For those who are curious, below I provide two
> >> sources
> >> >> of
> >> >> > > >> information:
> >> >> > > >>
> >> >> > > >> The first material to read is an excerpt from EFB 2nd ed page
> >> >> 81-83. Here,
> >> >> > > >> the authors demonstrate a typical misconception/misuse of both
> >> >> equivalent
> >> >> > > >> current dipole model and assumption of EEG source
> distributions
> >> >> (i.e.,
> >> >> > > >> small vs. large cortical patches). As a result, such an
> >> incorrect
> >> >> > > >> application leads to an implicit conclusion that there was a
> 5V
> >> >> (=5,000,000
> >> >> > > >> microV) source inside the brain. The authors' following
> >> concluding
> >> >> remark
> >> >> > > >> suggests there exists this known pitfall/misconception in
> >> >> literature
> >> >> > > >> reporting dipole source models in general (ouch...)
> >> >> > > >>
> >> >> > > >> *Of course, such extracellular potentials are too large by a
> >> >> factor of
> >> >> > > >> 1000 or more to be physiologically realistic. However, such
> >> >> considerations
> >> >> > > >> have not prevented reports of such magical dipoles. One
> wonders
> >> if
> >> >> this
> >> >> > > >> explains why source magnitudes are often not reported.*
> >> >> > > >>
> >> >> > > >>
> >> >>
> >>
> https://urldefense.com/v3/__https://drive.google.com/open?id=1LGyydB9ZucbBG9EQoZDKAg4CEUJlAWon__;!!Mih3wA!BJz_jI7amVJIO4yLx16kUNcvtKfKz2Vq2a8fn-buH6yEmuldbNRSNq8JZ679B42teXAZ4sz3nMIKlNimhKtMHlzFVrk$
> >> >> > > >>
> >> >> > > >> The second material to read is my manuscript under review, in
> >> >> which I
> >> >> > > >> described what I believe is the correct 'scaling law' of
> >> >> scalp-recorded EEG
> >> >> > > >> signals. Please find the section "Where did the small patch
> >> model
> >> >> come
> >> >> > > >> from, and what does it miss?" in Discussion.
> >> >> > > >>
> >> >> > > >>
> >> >>
> >>
> https://urldefense.com/v3/__https://www.medrxiv.org/content/10.64898/2026.01.23.26344529v1*libraryItemId=18612094__;Iw!!Mih3wA!BJz_jI7amVJIO4yLx16kUNcvtKfKz2Vq2a8fn-buH6yEmuldbNRSNq8JZ679B42teXAZ4sz3nMIKlNimhKtMsEnkBo8$
> >> >> > > >>
> >> >> > > >> I will submit a separate post about this manuscript, as this
> >> >> 'scaling law'
> >> >> > > >> is a tool for a larger aim.
> >> >> > > >>
> >> >> > > >> I have one more thing I wanted to report here, which would
> make
> >> a
> >> >> > > >> practical (and I believe substantial) contribution to this
> >> debate.
> >> >> But
> >> >> > > >> because Komal wants to keep it a low profile until he comes up
> >> >> with some
> >> >> > > >> proof of concept, I cannot tell you what it is ha ha. I
> believe
> >> >> that this
> >> >> > > >> solution provides a clear answer to the question "Can EEG
> >> measure
> >> >> the
> >> >> > > >> hippocampus' at least within the limitation of the
> conventional
> >> >> synaptic
> >> >> > > >> dogma + volume conductor theory.
> >> >> > > >>
> >> >> > > >> Makoto
> >> >> > > >
> >> >> > > > _______________________________________________
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> >> >> > > _______________________________________________
> >> >> > > To unsubscribe, send an empty email to
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> >> >> _______________________________________________
> >> >> To unsubscribe, send an empty email to
> >> >> eeglablist-unsubscribe at sccn.ucsd.edu or visit
> >> >> https://sccn.ucsd.edu/mailman/listinfo/eeglablist   .
> >> >
> >> >
> >> _______________________________________________
> >> To unsubscribe, send an empty email to
> >> eeglablist-unsubscribe at sccn.ucsd.edu or visit
> >> https://sccn.ucsd.edu/mailman/listinfo/eeglablist  .
> >
> >
> _______________________________________________
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