[Simnibs-discuss] normE values in MNI space

[Guilherme B Saturnino]

Which SimNIBS version are you using? In 3.1 we switched to using linear 
interpolation, so these artifacts should not happen anymore.


Best Regards,

Guilherme



On 19/03/2020 10.31, Jane Tan wrote:
> Hi Guilherme,
>
> Thanks for the reply. There are a good number of negative values (~22.5%).
> Do you have any suggestions on what I can do to attenuate the 
> artifacts? My main aim is to get the mean e-field for specific ROIs.
> For instance, would you recommend the use of normJ instead? I notice 
> that there are fewer negative values for normJ, and notably none in 
> the ROIs I am interested in.
>
> best regards,
> Jane
> ------------------------------------------------------------------------
> *From:* Guilherme B Saturnino <guilhermebs at drcmr.dk>
> *Sent:* Thursday, 19 March 2020 4:08 PM
> *To:* Jane Tan <Jane.Tan at murdoch.edu.au>; discuss at simnibs.org 
> <discuss at simnibs.org>
> *Subject:* Re: [Simnibs-discuss] normE values in MNI space
>
> Dear Jane,
>
>
>
> How many negative values are there? This is likely an artifact due to 
> spline interpolation of the electric field from the original space to 
> MNI space.
>
>
> Best Regards,
>
> Guilherme
>
>
> On 19/03/2020 06.06, Jane Tan wrote:
>> Hi SimNIBS Team,
>>
>> I found some negative values in my nifti volume for normE in MNI 
>> space, and I thought something must have gone awry during the 
>> segmentation process for my head mesh (created using headreco (with 
>> cat) on a MNI152 T1-weighted image).  However, the head mesh looks 
>> okay when I checked it with gmsh. The headreco_log doesn't seem to 
>> indicate any issues either - at least not to my untrained eye. I do 
>> not have access to freeview, and couldn't do a proper check via headreco.
>>
>> I'm also wondering if it might be due to normE not being very 
>> accurate as a result of registration to the MNI template?
>>
>> Your suggestions would be greatly appreciated. I am happy to provide 
>> my head mesh and segmentation results if that would be of any help.
>>
>> best regards,
>> Jane
>>
>>
>>
>>
>>
>>
>> Best regards,
>>
>>
>> Jane
>>
>>
>> **
>> **
>>
>>
>> _______________________________________________
>> Simnibs-discuss mailing list
>> Simnibs-discuss at drcmr.dk  <mailto:Simnibs-discuss at drcmr.dk>
>> https://mailman.drcmr.dk/mailman/listinfo/simnibs-discuss
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.drcmr.dk/pipermail/simnibs-discuss/attachments/20200319/dcbaa5c1/attachment-0001.html>