[Eeglablist] Meaning of ITC

Makoto Miyakoshi mataothefifth at yahoo.co.jp
Thu Apr 16 20:24:27 PDT 2009 

Dear Pal,

Thank you for the info. I'll check it.
Regarding a spatial filter, EEGLAB supports various ICAs and I use it.

Makoto

--- P$B>-%%(Bl Gunnar Larsson <Pal.Gunnar.Larsson at epilepsy.no> wrote:

> About Gevins
> 
> There are more papers. The Science paper from 1987 may be a place to
> start. In opposition to many others Gevins did get some nice results
> due to his deblurring method. I think you must implement some kind
> spatial filtering to use coherence on scalp recorded EEG.
> 
> P$B%;%e<+(Bl
> 
> > -----Opprinnelig melding-----
> > Fra: eeglablist-bounces at sccn.ucsd.edu [mailto:eeglablist-
> > bounces at sccn.ucsd.edu] P$B%;%e<+(B vegne av Makoto Miyakoshi
> > Sendt: 16. april 2009 04:15
> > Til: eeglablist at sccn.ucsd.edu
> > Emne: Re: [Eeglablist] Meaning of ITC
> > 
> > 
> > 
> > --- P$B<@</<'<'(Bl Gunnar Larsson <Pal.Gunnar.Larsson at epilepsy.no> wrote:
> > 
> > > From:P$B<'<=<'t@<-(Bl Gunnar Larsson<Pal.Gunnar.Larsson at epilepsy.no>
> > > To:'Makoto Miyakoshi' <mataothefifth at yahoo.co.jp> Date:Wed, 15
> Apr
> > > 2009 08:11:58 +0200
> > > Subject:RE: [Eeglablist] Meaning of ITC
> > >
> > > Dear Makoto
> > >
> > > > Dear Pal,
> > > >
> > > > Thank you for the reply. It is very informative and
> interesting...
> > > > almost exciting.
> > > >
> > > > It seems to me, however, that the term 'synchronization' is
> used in
> > > > different meanings between you and me. Maybe you mean it in a
> sense
> > > of
> > > > 'synchronized firing among neurons at a given moment', right?
> There
> > > are
> > > > actually papers that report inter-channel coherency, and that
> is
> > > > certainly a kind of synchronization. But the concept of ITC is
> > > 'inter-
> > > > trial'
> > > > synchrony: it compares EEG phases AMONG TRIALS and measure
> phase
> > > > variance, so it had nothing to do with inter-channel phase
> > > synchrony.
> > >
> > > You do have a point. I don't know your research at all. Is inter
> > trial
> > > between stimuli or between sessions or between persons? I have
> not
> > > thought this through, but I was thinking between stimuli and
> > something
> > > not unlike to bereitschaft-potentials, but mainly my pont was on
> the
> > > relation betwen bold and EEG.
> > >
> > > >
> > > > Maybe we'd better create a term 'Inter-neuronal coherency
> (INC)' in
> > > > contrast with inter-trial coherency (ITC).
> > > Coherency in EEG was very popular, but it did not lead to very
> much
> > > more than some papers. One of hte main reasons was that spatial
> > > filters were not applied (except by Gevins) and hence there were
> too
> > > much blurring of the findings. I guess you should look at Alan
> Gevins
> > > works from around 1984. He did 128 channel EEG and made arrows
> > showing
> > > coherences and latencies between brain areas. His illustrations
> have
> > > been widely used in the literature. To my knowledge he did not
> look
> > at
> > > ITC.
> > > >
> > > > I'm analyzing my EEG data and found some experimental effect in
> > > ITC,
> > > > but I have no idea how to interpret it... because theoretically
> it
> > > is
> > > > not related to neither ERSP (EEG power) nor BOLD.
> > > Back to bereitschaft - there is no expectance in this?
> > > >
> > > > I will ask EEGLABlist technicians how to post our
> communications to
> > > the
> > > > list. By the way, so far you are the only person who replied.
> My
> > > > gratitude is all yours (haha).
> > > >
> > >
> > > Regards
> > >
> > > P$B<'<=<'t@<-(Bl
> > >
> > > > Makoto
> > > >
> > > >
> > > >
> > > > --- P$B<><B<><1<><)<><)(Bl Gunnar Larsson
<Pal.Gunnar.Larsson at epilepsy.no>
> > wrote:
> > > >
> > > > > Dear Makoto
> > > > >
> > > > > First - I thought it went back to the list, but did not check
> to
> > > see
> > > > > that it did.
> > > > >
> > > > > My points was mostly towards the Nunez take on this;
> > > synchronization
> > > > > does not require energy. Hence synchrony comes out with high
> EEG-
> > > > power
> > > > > and no BOLD-effect. On the other hand, interneurons in cortex
> are
> > > so
> > > > > symmetrical that they do not show up on EEG, but consumes
> quite a
> > > bit
> > > > > of energy and will be well seen in fMRI.
> > > > >
> > > > > According to the above, your phase locking(?) would be
> expected
> > > to
> > > > > influence EEG-power but not BOLD (or ?).
> > > > >
> > > > > Another point from Nunez: If you have a million stochastic
> firing
> > > > > neurons, they would give a resultant amplitude of A*sqrt(n)
> where
> > > A
> > > > is
> > > > > the amplitude and n is number of neurons. However, when they
> are
> > > > > synchronized, the amplitude is n*A. So a million neurons will
> > > show
> > > > > same amplitude as 1000 synchronized neurons! This gives that
> > > small
> > > > > systems may dominate the EEG you record.
> > > > >
> > > > > P$B<><)<><?<><)<#<(<></(Bl
> > > > >
> > > > > -----Opprinnelig melding-----
> > > > > Fra: Makoto Miyakoshi [mailto:mataothefifth at yahoo.co.jp]
> > > > > Sendt: 14. april 2009 03:54
> > > > > Til: P$B<><)<><?<><)<#<(<></(Bl Gunnar Larsson
> > > > > Emne: RE: [Eeglablist] Meaning of ITC
> > > > >
> > > > > Dear Pal,
> > > > >
> > > > > Thank you for your fast response and information.
> > > > > Neurovascular coupling is the essential phenomenon with BOLD
> and
> > > it
> > > > > has totally different time constant than EEG... that is fine
> with
> > > me.
> > > > > That said, what I'm wondering is the meaning of ITC. On the
> one
> > > hand,
> > > > > ERSP is a measure of EEG power, which most likely reflects
> sum of
> > > > > regional neuronal activities, which should be associated with
> > > BOLD
> > > > via
> > > > > neurovascular coupling (in principle). On the other hand, ITC
> has
> > > > > nothing to do with EEG power, since it is a measure of
> > > inter-trial
> > > > > phase variance, therefore it should not affect BOLD either.
> Then,
> > > > what
> > > > > is the meaning of ITC in contrast with ERSP/BOLD?
> > > > >
> > > > > By the way, your response does not seem to be sent to EEGLAB
> > > list.
> > > > > Why don't we re-send it to the list?
> > > > >
> > > > > Makoto
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > --- P$B<><@<><D<><@<><3<><@<><+<><@<><+(Bl Gunnar Larsson
> > <Pal.Gunnar.Larsson at epilepsy.no>
> > > wrote:
> > > > >
> > > > > > I think you should read the paper by PL Nunez on the
> relation
> > > > > between
> > > > > > EEG and fMRI from 2000 (or 1999?). EEG and BOLD is very
> > > different
> > > > > > entities. Also, the EEG- parameters are direct functional
> > > measures
> > > > > > which gives responsen from a few miliseconds to some
> seconds
> > > > > > (Pfurtscheller). BOLD on the other hand, is the change in
> > > > > oxygenation
> > > > > > due to change in bloodflow due to change in energy
> consumption
> > > due
> > > > > > change in activity. Hence the effect is very indirect and
> shows
> > > a
> > > > > > maximum after some 5s. E.G. AM Dale et al has shown some
> nice
> > > use
> > > > > of
> > > > > > the BOLD and EEG/MEG so there no reason to discard one,
> just
> > > use
> > > > > with
> > > > > > care.
> > > > > >
> > > > > > P$B<><@<><+<><@<><A<><@<><+<><%<><*<><@<><1(Bl
> > > > > >
> > > > > > -----Opprinnelig melding-----
> > > > > > Fra: eeglablist-bounces at sccn.ucsd.edu
> > > > > > [mailto:eeglablist-bounces at sccn.ucsd.edu]
> P$B<><@<><+<><@<><A<><@<><+<><%<><*<><@<><1(B
> > vegne av
> > > > Makoto
> > > > > > Miyakoshi
> > > > > > Sendt: 10. april 2009 11:25
> > > > > > Til: eeglablist at sccn.ucsd.edu
> > > > > > Emne: [Eeglablist] Meaning of ITC
> > > > > >
> > > > > > Dear experts,
> > > > > >
> > > > > > Let me take a question about a basic physiology.
> > > > > > In my intuition, ERSP (i.e. EEG power) is related to
> neuronal
> > > > > > activation, either firing frequency or number of firing
> cells.
> > > On
> > > > > the
> > > > > > other hand, ITC (i.e. inter-trial EEG phase) is NOT
> directly
> > > > > related
> > > > > > to them. So, by observing ITC, we may be observing some
> already
> > > > > > systematized temporal responsibility of the given network,
> > > which is
> > > > >
> > > > > > too complicated and abstract to imagine, compared to the
> case
> > > of
> > > > > > neuronal firing simply increasing/decreasing.  Does it
> mean,
> > > then,
> > > > > ITC
> > > > > > is a totally different index than, for example, BOLD?
> > > > > >
> > > > > > Makoto
> > > > > > _______________________________________________
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> > > > >
> > >
> > >
> 
>

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