[Eeglablist] Fw: Re: ECG Channel Inclusion in ICA and ICLabel Steps

Tue Aug 6 00:41:40 PDT 2024

Thanks Scott for the great input on the ballistocardiogram and the Hall effect. Very interesting.

John, cardiac field artifacts (CFAs) are a real thing, and yes we do see ECG in the EEG signals sometimes, and yes they travel through volume conduction via subcutaneous and cutaneous tissues. I've seen them with my own eyes using state-of-the art systems many times (Biosemi, using CMS/DRL scheme and gel to get as good impedance as you can get, etc.). I know how to recognize heartbeats on a EEG time series relative to other technical artifacts, thank you. If you don't believe me, see for this great reference I just rediscovered that is aligned with Scott's comment on the hemispheric asymmetry and diagonal property: https://urldefense.com/v3/__https://onlinelibrary.wiley.com/doi/10.1111/psyp.14323__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkjGPgLFYw$ 

Here is figure 4 from the paper: https://urldefense.com/v3/__https://figshare.com/articles/figure/Figure_4_of_Cardiac_field_effects_on_the_EEG/26501227?file=48195181__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkjixC9XTw$ 

(I can send the PDF if you want)

Also, see these relevant references:
https://urldefense.com/v3/__https://link.springer.com/article/10.1007/BF02351030__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8Wkh9jj84Gw$ 

https://urldefense.com/v3/__https://pubmed.ncbi.nlm.nih.gov/31051293/__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkiAtPN2GQ$ 
https://urldefense.com/v3/__https://pubmed.ncbi.nlm.nih.gov/9146492/__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkhuoGINog$ 

https://urldefense.com/v3/__https://ieeexplore.ieee.org/document/6609929__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkgPmPQTTQ$ 

https://urldefense.com/v3/__https://www.mdpi.com/1424-8220/21/19/6364__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkigIRZDuw$  (you'll probably find this one interesting for you work on infants)
https://urldefense.com/v3/__https://onlinelibrary.wiley.com/doi/10.1002/hbm.25535__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8Wkhpkt86hw$  (on the ballistocardiogram artifacts)

And if I recall correctly, The Electric fields of the Brain has a section on it as well (for Makoto)

-  But if you invert the ICA channels that do not have the ICA ECG channel, the resulting EEG channels would look similar if not identical to the original EEG channels.

Not sure what this means. What is a ICA channel? do you mean a component? and "Look similar" is a big word in EEG research. Do you see ERPs when you look at the raw time series?

-  Also the size of the ECG (mV rather than milliV) would probably dominate the ICA components with several components being dedicated to ECG.

Yes I've addressed that earlier, You can rescale the signal to EEG range to avoid this issue.

- I don't know of a "HEP" per se, and am not familiar with the citations give by Cedric

Look into it maybe since you think you know the basics.

- Wanze Xie is examining cardiac cycle effects on VEP's

Yes there is better detection when stimuli were presented during diastole, this is well documented (e.g., https://urldefense.com/v3/__https://www.nature.com/articles/nn.3671__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkioxcrIlQ$ , https://urldefense.com/v3/__https://www.sciencedirect.com/science/article/pii/S1746809423007486?via*3Dihub__;JQ!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkijT0azHg$ ). These studies are very interesting, and I am aware of them. However, this is off topic for this conversation that is about whether ICA is separating the CFAs as intended, or also removing relevant brain activity underlying the processing of cardiovascular activity, and whether there is such thing or if HEPs are simply reflecting blood flow changes in the brain via the pulsating system: https://urldefense.com/v3/__https://fluidsbarrierscns.biomedcentral.com/articles/10.1186/2045-8118-8-5__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8Wkg7DK5x6g$ 

-  Of all the ways Cedric lists how the heart interacts with the brain, none involve electrical conduction; they are indirect (blood pressure; vagal efferents controlling RSA and HR; volume conduction via CSF). This is different from EOG/EMG where the electrical signal is deemed to be an artifact and ICA is being used to eliminate an unwanted electrical signal

Yes it is different because this was a different topic. I was asking if you remove CFAs (which you don't believe in) with ICA, do HEPs represent pure brain response to heartbeats. I was exploring the possibility that there could still be other internal CFAs like volume conduction through CSF (contained in the vertebral columns that is highly conductive) or arteries. And HR/BP information sent by baroreceptors through the vagus nerve is electrical, isn't it? It's like saying the brain does not communicate via electrical conduction because of synapses. The baroreceptors convert the mechanical deformation into an electrical signal, via opening/closing of ion channels in the receptor cells, leading to changes in membrane potential (i.e., action potential transmitted along the afferent nerve fibers). Anyways... this is a off topic, the point was about deciphering between CFAs and genuine communication between the brain and the heart. This conversation was specifically about how the heart may directly or indirectly affect brain activity, which is why I was mentioning new analyses of causal interactions.

Cedric

----------------------------------------------------------------------
From: Richards, John via eeglablist <eeglablist at sccn.ucsd.edu>
Date: On Monday, August 5th, 2024 at 6:24 PM
Subject: Re: [Eeglablist] Fw: Re: ECG Channel Inclusion in ICA and ICLabel Steps
To: Makoto Miyakoshi <mmiyakoshi at ucsd.edu>, EEGLAB List <eeglablist at sccn.ucsd.edu>CC: Wanze Xie <wanze.xie at pku.edu.cn>

Back to basics... The ECG signal rarely shows up in the EEG electrodes. If your EEG electrodes have low impedance and ECG is grounded or is part of the EEG recording, then it is not evident in the EEG electrodes. If it does show up its likely there is a recording artifact, poor connection, etc. This is different than EOG/EMG where the muscles or eye activity produces currents that flow into the EEG recordings. I presume that most people using ICA with EOG/EMG are doing it to remove an unwanted signal from the brain signal. The ECG signal also has different amplitude, frequency characteristics, is not a regular rhythmic electrical wave like EEG, is generated by the heart muscle and spreads via muscle/skin/bones through the lower body but not the head. Cedric below says it spreads via skin to the scalp. I'm not sure about this, we do not see ECG signals in the EEG. Its possible its an amplifier effect--we have recorded our ECG signals with the same amp as the EEG (EGI), and its possible that something in the amp like common mode rejection is doing this. I suppose if you put it in the ICA with the EEG you would have some ICA channels with very large amplitude that represent the ECG signal. But if you invert the ICA channels that do not have the ICA ECG channel, the resulting EEG channels would look similar if not identical to the original EEG channels. Also the size of the ECG (mV rather than milliV) would probably dominate the ICA components with several components being dedicated to ECG. I don't know of a "HEP" per se, and am not familiar with the citations give by Cedric. Of all the ways Cedric lists how the heart interacts with the brain, none involve electrical conduction; they are indirect (blood pressure; vagal efferents controlling RSA and HR; volume conduction via CSF). This is different from EOG/EMG where the electrical signal is deemed to be an artifact and ICA is being used to eliminate an unwanted electrical signal. Wanze Xie is examining cardiac cycle effects on VEP's. This involves identifying parts of the ECG signal and then doing VEP summarizing for stimuli presented in the different parts of the cycle. I think his results were that stimuli presented in the T-P interval showed larger VEPs than stimuli presented in other intervals. My explanation of this is that the T-P interval is part of "diastole", HR slows down due to vagal efferent activity, blood pressure decreases and the baroreceptors are less active, and likely the brain is more sensitive to external stimuli. The PQRS interval (P to T, or QRT) is "systole" when there is a large electrical signal across the ventricles and they constrict, increasing blood pressure, the baroreceptors in the aortic arch immediately respond and signal to brain, the brain is less sensitive to external stimuli. I don't think this decrease and increase of HR will be evident in a synchronous manner with EEG; and probably would not show up in the ICA. Note that its not the electrical signal of the ECG doing this, its an indirect effect of the baroreceptor reflex. Again, unlike EOG/EMG which transmit current across the scalp, no current is coming from the heart in this effect. I've cc'ed Wanze on this. He might have a better explanation for his finding, and some perspective on the ECG/EMG/EOG/EEG ICA question. John
On Monday, August 5th, 2024 at 8:24 PM, Scott Makeig <smakeig at gmail.com> wrote:

> Jason and all -
>
> There is a heartbeat signal - in EEG-in-fMRI (the 'ballistocardiogram'). Averaging on the R wave and visualizing the scap channels result in animation shows a potential that flows (up) the carotid and then up and across the scalp diagonally. The 'ballistic' title came from the supposition that the scalp electrodes moving in the high-magnetic field of the scanner. But I hard a physicist speculate that it might (also) be some sort of vascular 'Hall effect' [Wikipedia: The Hall effect is the production of a [potential difference](https://urldefense.com/v3/__https://en.wikipedia.org/wiki/Voltage__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkjxHaKhAw$ ) (the Hall voltage) across an [electrical conductor](https://urldefense.com/v3/__https://en.wikipedia.org/wiki/Electrical_conductor__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkjYz_OLlg$ ) that is [transverse](https://urldefense.com/v3/__https://en.wiktionary.org/wiki/transverse__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkiOytGljQ$ ) to an [electric current](https://urldefense.com/v3/__https://en.wikipedia.org/wiki/Electric_current__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkjbBoUNMg$ ) in the conductor and to an applied [magnetic field](https://urldefense.com/v3/__https://en.wikipedia.org/wiki/Magnetic_field)*perpendicular*(https:/*en.wiktionary.org/wiki/perpendicular__;W10v!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkiR_NGpgQ$ ) to the current. It was discovered by [Edwin Hall](https://urldefense.com/v3/__https://en.wikipedia.org/wiki/Edwin_Hall__;!!Mih3wA!BifpUDc8xyPyCbkJv3B0tNf-M8eT43btFlApvOkbCDtKTPP6aDA44LWY5WvtyZ_4dgqW-bfpDMvjBH-8WkjIovJIeQ$ ) in 1879]. Scalp maps for ECG-account independent components look similar - though I don't believe that the averaged scalp potential movie for an EEG session should exhibit the same moving map....
>
> Scott
>
> On Mon, Aug 5, 2024 at 5:13 PM japalmer29--- via eeglablist <eeglablist at sccn.ucsd.edu> wrote:
>
>> Hi Cedric and Makoto,
>>
>> My thoughts re the heartbeat source--I believe the heartbeat itself is mainly dipolar viewed from the "far field" of the scalp electrodes, which is why it shows up as a rainbow looking map. The actual dynamics of the EM field are more complex, but we mainly see only one component if any for the heartbeat.
>>
>> If there is a heartbeat related brain signal, I think it would likely be blood flow related, but we don't really see such components. I don't think such a component would be part of the heart located component since the blood flow would not be instantaneously synched to the heartbeat. All standard ICA components are only supposed to be instantaneously independent.
>>
>> Best,
>> Jason
>>
>> -----Original Message-----
>> From: eeglablist <eeglablist-bounces at sccn.ucsd.edu> On Behalf Of Cedric Cannard via eeglablist
>> Sent: Monday, August 5, 2024 4:47 PM
>> To: EEGLAB List <eeglablist at sccn.ucsd.edu>
>> Subject: [Eeglablist] Fw: Re: ECG Channel Inclusion in ICA and ICLabel Steps
>>
>> Hi Makoto,
>>
>> Sorry for the typo. As you can guess, I meant "I do not believe including auxiliary channels violates ICA assumptions."
>>
>>> Tony Bell is a legend
>>
>> haha :)
>>
>>> For example, concatenating millivolt-range signals with microvolt-range signals for decomposition may cause unexpected trouble.
>>
>> Yes, I generally rescale the ECG signal to the EEG range if the ECG scale is vastly different, so ICA does not prioritize the larger ECG signals over the smaller EEG ones, which gives better results.
>>
>>> Then ICA would not identify non-brain artifacts, right?
>>
>> Why? Non-brain artifacts have independent sources. My point was that, as you summarized, ICA assumes sources to be independent, mixed, and non-gaussian, not that the sources of all signals are EPSP/IPSPs from pyramidal neurons.
>>
>>> I'm rather curious to know if heartbeat-evoked potential is a real thing. For example, if I decompose a heartbeat IC which typically has a broad and dipolar projection from the depth. Is there any neuronal contribution there? If yes, then the heartbeat IC is contributed by both the heart and the brain. If no, it is generated only by the heart. Which is the case?
>>
>> I agree and am wondering the same thing. And I don't think there is an answer to this yet. removing heart ICs may remove both the CFAs and the relevant neuronal-related HEP. Ideally, heart ICs would capture the cardiac field artifacts (CFA) which travel by volume conduction (e.g., skin) and are picked up by scalp EEG electrodes. The broad and dipolar spatial properties of the heart ICs reflect these CFAs (i.e., the source is non-neuronal). And HEPs (after removing these CFAs) would only reflect neuronal processing of heart activity.
>> I think one potential way of answering this would be to have intracranial electrodes time-locked to scalp electrodes, mark the R-peaks in both, and compare. But even then, heart activity can travel to the brain via various direct and indirect pathways: directly via the vagus nerve, indirectly via volume conduction through the spinal cord (surrounded by conductive CSF) and conductive arteries, or via blood pressure-related activity detected by baroreceptors/chemoreceptors.
>>
>> I am currently developing a multivariate method that would provide more information on the synchronization (coherence & partial coherence), system response (transfer function matrix, spectral matrix, inverse spectral matrix), and causal interactions (directed coherence, directed transfer function, partial directed coherence) between heart and EEG signals. hopefully, that can provide some insights (direct, indirect interactions and direction of the interaction).
>>
>> I think what provides some answer is the growing body of literature showing meaningful associations between HEP and interoception and integration of internal bodily states, highlighting brain areas known to be involved in these processes from the neuroimaging literature, e.g. insula, ACC, somatosensory cortex.
>>
>> Some good references for HEP:
>> https://urldefense.com/v3/__https://pubmed.ncbi.nlm.nih.gov/31051293/__;!!Mih3wA!A7XPAnqNlQiz9pvotlbJTJbG2_n0TrNLB20H1cJLZDjdmMz8JsfHFIdXHQufx-wO2xcvGmCGkuOn8VQfYj8XKL4HCQ$
>>
>> https://urldefense.com/v3/__https://pubmed.ncbi.nlm.nih.gov/22541740/__;!!Mih3wA!A7XPAnqNlQiz9pvotlbJTJbG2_n0TrNLB20H1cJLZDjdmMz8JsfHFIdXHQufx-wO2xcvGmCGkuOn8VQfYj8D2qUf-A$
>>
>> https://urldefense.com/v3/__https://pubmed.ncbi.nlm.nih.gov/28651745/__;!!Mih3wA!A7XPAnqNlQiz9pvotlbJTJbG2_n0TrNLB20H1cJLZDjdmMz8JsfHFIdXHQufx-wO2xcvGmCGkuOn8VQfYj9BgOZjfw$
>>
>> Cedric
>>
>> ------- Forwarded Message -------
>> From: Makoto Miyakoshi via eeglablist <eeglablist at sccn.ucsd.edu>
>> Date: On Monday, August 5th, 2024 at 7:59 AM
>> Subject: Re: [Eeglablist] ECG Channel Inclusion in ICA and ICLabel Steps
>> To: EEGLAB List <eeglablist at sccn.ucsd.edu>
>>
>>> Hello John and
>>>
>>> Cedric
>>>
>>>
>>> ,
>>>
>>> This double negative makes it difficult to understand what you are
>>> trying to say, Cedric.
>>>
>>> > I do not believe including auxiliary channels does not violate ICA
>>>
>>> assumptions.
>>>
>>> You are saying that including ECG violates ICA's assumption, but your
>>> claim seems opposite.
>>>
>>> ICA's assumptions are, off the top of the head,
>>>
>>> - The sources are non-Gaussian
>>> - The sources are linearly independent
>>> - The sources are linearly and instantly mixed
>>> - Tony Bell is a legend
>>>
>>> So ECG channels may be included in ICA with no problem in theory.
>>> However, if empirical observations recommend otherwise, there may be
>>> some reason that is specific to each application which is worth
>>> investigating. For example, concatenating millivolt-range signals with
>>> microvolt-range signals for decomposition may cause unexpected trouble.
>>>
>>> > It does not inherently assume that all sources must be of the same
>>> > nature
>>>
>>> or originate from EPSP/IPSPs from pyramidal neurons in cortical gyri,
>>> does it?
>>>
>>> Then ICA would not identify non-brain artifacts, right?
>>>
>>> I'm rather curious to know if heartbeat-evoked potential is a real thing.
>>> For example, if I decompose a heartbeat IC which typically has a broad
>>> and dipolar projection from the depth. Is there any neuronal
>>> contribution there? If yes, then the heartbeat IC is contributed by
>>> both the heart and the brain. If no, it is generated only by the heart. Which is the case?
>>>
>>> Makoto
>>>
>>>
>>>
>>> On Mon, Aug 5, 2024 at 12:58 AM Cedric Cannard via eeglablist <
>>> eeglablist at sccn.ucsd.edu> wrote:
>>>
>>> > Dear John,
>>> >
>>> > This is the same debate as including EOG for separating and
>>> > extracting ocular components (isn't that common practice?). The only
>>> > reason why you can get away without EOG channels is that ocular
>>> > activity is so large compared to EEG, so easy to identify as an
>>> > independent source. However, cardiac artifacts are difficult to
>>> > identify without an explicit reference signal (except occasionally
>>> > in some individuals where you can see them visually in the raw time series).
>>> >
>>> > Someone will correct me if I'm wrong, but I do not believe including
>>> > auxiliary channels does not violate ICA assumptions. ICA is an
>>> > algorithm designed to separate a mixture of signals into
>>> > statistically independent components. It does not inherently assume
>>> > that all sources must be of the same nature or originate from
>>> > EPSP/IPSPs from pyramidal neurons in cortical gyri, does it?
>>> >
>>> > By providing a clear reference for ECG artifacts, ECG channels can
>>> > enhance the accuracy of this separation in my experience, in line
>>> > with Sofia's observation. In fact, this is a method supported by my
>>> > new BrainBeats plugin (along with HEP/HEO and HRV analysis which
>>> > implements validated algorithms and guidelines via command line or
>>> > GUI). See here for a step-by-step tutorial:
>>> > https://urldefense.com/v3/__https://www.jove.com/t/65829/author-spot
>>> > light-advancing-study-brain-heart-interplay-with__;!!Mih3wA!CWCJFZKu
>>> > 2zYD1n7sKo1ur_bO9g_iWhAy9vSTS18Bf-jfmH6errEXOVCDaXANh_5ukcj1Wajfh_MI
>>> > n3CPFGGRV09qjA$
>>> > And Github repo:
>>> > https://urldefense.com/v3/__https://github.com/amisepa/BrainBeats__;
>>> > !!Mih3wA!CWCJFZKu2zYD1n7sKo1ur_bO9g_iWhAy9vSTS18Bf-jfmH6errEXOVCDaXA
>>> > Nh_5ukcj1Wajfh_MIn3CPFGGKS9yf5A$
>>> >
>>> > Sofia, my question is: Why are you using ICA in the context of HEP?
>>> > You generally want to keep ECG-related activity for HEP. Do you
>>> > suspect the HEP is a CFA? I have wondered about that but haven't found a work-around.
>>> >
>>> > Curious to hear more on this!
>>> >
>>> > Cedric Cannard
>>> >
>>> > On Thursday, August 1st, 2024 at 7:08 AM, Richards, John via
>>> > eeglablist < eeglablist at sccn.ucsd.edu> wrote:
>>> >
>>> > > Don't include ECG in the EEG signal for ICA. For various technical
>>> > > reasons (amplitude, frequency, signal spikes, location) and
>>> > > theoretical ones (its NOT a brain signal; you want to correlate ECG and EEG).
>>> > >
>>> > > See poster by Wanze Xie at ICIS, or contact him. He has
>>> > > synchronized cardiac cycles and ERPs. His techniques might be
>>> > > useful and he has some very interesting VEP/cardiac cycle data.
>>> > >
>>> > > John
>>> > >
>>> > > ***********************************************
>>> > > John E. Richards
>>> > > Carolina Distinguished Professor
>>> > > Department of Psychology
>>> > > University of South Carolina
>>> > > Columbia, SC 29208
>>> > > Dept Phone: 803 777 2079
>>> > > Fax: 803 777 9558
>>> > > Email: richards-john at sc.edu
>>> >
>>> > https://urldefense.com/v3/__https://jerlab.sc.edu/__;!!Mih3wA!B4rXaM
>>> > GVhHYr_2oHmmQc94PJcfhiYYPWsZNqJtpm0CRKhOTeHaXWrkUCGI-mcxaW1b2qR1YWJv
>>> > 1lJrPrNV29FIao1z4gCQ$
>>> >
>>> > > ***********************************************
>>> > >
>>> > > -----Original Message-----
>>> > > From: eeglablist eeglablist-bounces at sccn.ucsd.edu On Behalf Of
>>> > > Sofia Amaoui via eeglablist
>>> > >
>>> > > Sent: Thursday, August 1, 2024 8:54 AM
>>> > > To: eeglablist at sccn.ucsd.edu
>>> > > Subject: [Eeglablist] ECG Channel Inclusion in ICA and ICLabel
>>> > > Steps
>>> > >
>>> > > Dear all,
>>> > >
>>> > > We are conducting a Heart-Evoked Potential (HEP) study using EEG
>>> > > signals that are time-locked to R-peak via ECG. Our preprocessing
>>> > > pipeline is being implemented with EEGLAB, including the ERPLAB
>>> > > and HEPLAB plugins. As part of this process, we employ Independent
>>> > > Component Analysis (ICA) and ICLabel to identify ocular and cardiac field artefacts (CFA).
>>> > >
>>> > > A key question has arisen regarding including the ECG channel in
>>> > > the ICA and ICLabel steps. Our preliminary findings show that when
>>> > > we include it, CFA classification is much higher.
>>> > >
>>> > > We are seeking your insights on whether the inclusion of the ECG
>>> > > channel is aiding in the identification of CFA components or if it
>>> > > might be compromising EEG information of interest by focusing on
>>> > > identifying and removing CFA.
>>> > >
>>> > > Thank you for your time and assistance.
>>> > >
>>> > > Best regards,
>>> > >
>>> > > Sofia Amaoui,
>>> > > _______________________________________________
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> --
>
> 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](http://sccn.ucsd.edu/%7Escott)