[Eeglablist] Dipole's moment unit

[Makoto Miyakoshi]

> For a ground truth dipole right underneath an electrode with moment [1 0
0] in Fieldtrip, I got estimated dipole moment [10^6 0 0] in EEGLAB. I
guess this corresponds to A -> nA.

Actually, this statement is wrong because A -> nA is x10^9, not x10^6.
I found that the leadfield matrix I used is scaled as follows

scalingFactor = ft_scalingfactor('V/(A*m)', 'uV/(nA*m)');

This scaling factor is 10^-3. I think this explains the difference between
10^9 and 10^6.
The reason why my code (which is based on some material I took from one of
Fieldtrip tutorials) uses this scaling factor is because so that when you
multiply the dipole moment you can obtain the potential at the electrode in
micro V, it says.

Makoto

On Wed, Jul 19, 2023 at 4:35 PM Makoto Miyakoshi <mmiyakoshi at ucsd.edu>
wrote:

> Dear Saina,
>
> I LOVE your question. I guess how many of us can answer your question.
> For a ground truth dipole right underneath an electrode with moment [1 0
> 0] in Fieldtrip, I got estimated dipole moment [10^6 0 0] in EEGLAB. I
> guess this corresponds to A -> nA.
>
> Makoto
>
> On Fri, Jul 7, 2023 at 2:57 AM Namazifard, Saina via eeglablist <
> eeglablist at sccn.ucsd.edu> wrote:
>
>> Dear all,
>>
>> I have a question about using the DIPFIT option and I appreciate it if
>> you could help me.
>> When I choose the Fine fit, there is a window showing the dipole's
>> moment. Does anyone know what the unit is here? I believe it should be
>> nA.m, but I want to make sure I am right.
>>
>> Thank you for your help.
>> Saina
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