[Eeglablist] Why most of good 'brain' ICs are 'dipolar' with show 'red'-centered scalp topos, although 2/3 of the cortex is in sulci?

[K Jeffrey Eriksen]

This topic holds a special place in my heart, so I could not help sorting the search results to show the most recent literature (2020-2024).

-Jeff

Google Scholar - head conductivity and EEG - 2020+ only

Wednesday, January 10, 2024
10:28 AM

Inter-subject variability of skull conductivity and thickness in calibrated realistic head models
M Antonakakis, S Schrader, Ü Aydin, A Khan, J Gross… - Neuroimage, 2020 - Elsevier
… Skull conductivity has a substantial influence on EEG and combined EEG and MEG source
… -level calibration procedure to estimate skull conductivity individually in a group study with …

Evaluation of skull conductivity using SCALE head tissue conductivity estimation using EEG
ZA Acar, S Makeig - … Conference of the IEEE Engineering in …, 2022 - ieeexplore.ieee.org
… conductivity ratios (BSCR) by building head models for ten young adult participants across
sixteen different EEG … Five of the subjects participated in 2 or 3 separate EEG sessions. For …

A novel method for calibrating head models to account for variability in conductivity and its evaluation in a sphere model
S Schrader, M Antonakakis, S Rampp… - Physics in Medicine …, 2020 - iopscience.iop.org
… conductivity. In this study, we present an automatic pipeline to calibrate head models with
respect to skull conductivity … Calibrated head modeling can improve EEG and combined EEG/…

Impact of skull-to-brain conductivity ratio for high resolution EEG source localization
G Demoulin, E Pruvost-Robieux, A Marchi… - Biomedical Physics …, 2021 - iopscience.iop.org
… Dipoles computed with a head model using a skull-to-brain conductivity ratio of 1/40 were
4.3 mm closer to the anterior commissure than dipoles obtained with 1/80 ratio (p = 0.0048). …

Effect of structural complexities in head modeling on the accuracy of EEG source localization in neonates
H Azizollahi, A Aarabi, F Wallois - Journal of Neural Engineering, 2020 - iopscience.iop.org
… However, the effect of uncertainty in head tissue conductivities except for the skull on
EEG source localization can be expected to be less pronounced, as we have previously …

The neurophysiology of EEG and the physics of the head: theory and application for spontaneous EEG
D Miklody - 2020 - search.proquest.com
… human head drastically decrease the spatial resolution of EEG. … EEG is highly autocorrelated
while additionally non-… head model, sensor position and homogeneous conductivity …

Age-related EEG power reductions cannot be explained by changes of the conductivity distribution in the head due to brain atrophy
M He, F Liu, A Nummenmaa, M Hämäläinen… - Frontiers in Aging …, 2021 - frontiersin.org
… of varying CSF and skull conductivities. This analysis shows that changes in conductivity
across wide ranges can alter the EEG attenuation by at most 0.5 dB. EEG signal attenuation is …

Assessing the effects of head modelling errors and measurement noise on EEG source localization accuracy in preterm newborns: A single‐subject study
H Azizollahi, A Aarabi, K Kazemi… - European Journal of …, 2023 - Wiley Online Library
… of inaccuracy in the conductivity of head tissues and head model structural deficiencies
on the accuracy of EEG source analysis in premature neonates. A series of EEG forward and …

Evaluation of Performance for Human In-Vivo Conductivity Estimation from EEG and sEEG Recorded in Simultaneous with Intracerebral Electrical Stimulation
H Altakroury, L Koessler, R Ranta, J Hofmanis… - arXiv preprint arXiv …, 2022 - arxiv.org
… In this study, we perform in-vivo conductivity estimation in five-compartment FEM head
models of epileptic patients with the sEEG and EEG recordings acquired during IES. The …

The influence of the head model conductor on the source localization of auditory evoked potentials
S Conte, JE Richards - Brain Topography, 2021 - Springer
… magnitude obtained with 10 different head models on the EEG forward solution. Starting from
… This value corresponds to the conductivity value utilized for the WM segment in our head …


-----Original Message-----
From: eeglablist <eeglablist-bounces at sccn.ucsd.edu> On Behalf Of Scott Makeig via eeglablist
Sent: Wednesday, January 10, 2024 8:46 AM
To: Евгений Машеров <emasherov at yandex.ru>
Cc: eeglablist at sccn.ucsd.edu
Subject: Re: [Eeglablist] Why most of good 'brain' ICs are 'dipolar' with show 'red'-centerd scalp topos, although 2/3 of the cortex is in sulci?

There was an abstract presentation at a company-sponsored? session at OHBM several years ago.  I am sure Don is still interested <dmtucker at mac.com>

Scott

On Tue, Jan 9, 2024 at 12:33 AM Евгений Машеров <emasherov at yandex.ru> wrote:

> Thank you. I would like to clarify his methodology. Perhaps it is
> described in detail somewhere? It seems to me that the frequency at
> which the impedance is measured may be significant here.
>
> Eugen Masherov
>
> > Yes, this electrical stimulation approach was attempted by Don
> > Tucker's
> EGI
> > group for many years - with results that were not encouraging, the
> problem
> > being that almost all the injected current flows through the scalp,
> > whose local and time-varying conductivity also then has significant effect...
> The
> > SCALE approach treats the independent component signals compatible
> > with
> an
> > effective source in cortex (having a strongly dipolar scalp
> > projection
> with
> > equivalent dipole located in brain) as cortical stimulations, and
> > iteratively finds the (single) skull conductivity value that
> > minimizes reconstruction error of the brain sources to 'sparse,
> > compact, and smoothly' varying distribution (sometime, two
> > bilaterally near-symmetric distributions) on the imaged cortical
> > surface - using an electrical forward problem head model constructed
> > from an individual MR image - the SCS source inversion algorithm of
> > Cao Cheng. Our next step should be to build a multidimensional skull
> > conductivity map. Again, we
> are
> > attempting to put the SCALE software on NSG (
> https://urldefense.com/v3/__http://www.nsgportal.org__;!!Mih3wA!BNS_5a
> ZCEDYflkuo2qfpDZgsY0Z-xv87AU3QM1QiNdQklstxqDvGifU6oaUANNcbLSF18LJVuTtk
> Yo2KIrZI$
> ) for free
> > use.
> >
> > Scott Makeig
> >
>


--
Scott Makeig, Research Scientist and Director, Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California San Diego, La Jolla CA 92093-0559, http://sccn.ucsd.edu/~scott _______________________________________________
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