[FieldTrip] Simbio works with ft_volumereslice but leadfield

Julian Keil julian.keil at gmail.com
Thu Apr 14 09:48:05 CEST 2016


Hi Rajat,

what do you mean by "way too long"?

Have you tried setting the resolution of the mesh in the call to ft_prepare_mesh prior to ft_prepare_headmodel?

Setting it to cfg.resolution = 5 (which changes the mesh resolution from the default 1mm to 5mm) greatly sped up the mesh preparation and leadfield computation in my case.
Please beware however that I use a rather old FT-Version as I don't have a current Matlab Version, so the functionality might have changed.

Good Luck,

Julian

********************
Dr. Julian Keil

AG Multisensorische Integration
Psychiatrische Universitätsklinik
der Charité im St. Hedwig-Krankenhaus
Große Hamburger Straße 5-11, Haus 2
10115 Berlin

Telefon: +49-30-2311-1879
Fax:        +49-30-2311-2209
http://psy-ccm.charite.de/forschung/bildgebung/ag_multisensorische_integration

Am 13.04.2016 um 16:25 schrieb Rajat Thomas:

> Dear all,
> 
> Last week I asked for help with Simbio and after following the suggestion of volume reslicing magically the
> simbio based headmodel was created.
> 
> But my leadfield calculations are taking way too long.
> It is a 128^3 grid and am running it on my desktop. (2.4 GHz, plenty of memory 32GB)
> 
> Could anyone give me a rough ball park on how long it should take to create a leadfield?
> 
> Thank you.
> Rajat
> 
> 
> 
> Rajat Mani Thomas
> Social Brain Lab
> Netherlands Institute for Neuroscience
> Amsterdam
> 
> ________________________________________
> From: fieldtrip-bounces at science.ru.nl <fieldtrip-bounces at science.ru.nl> on behalf of fieldtrip-request at science.ru.nl <fieldtrip-request at science.ru.nl>
> Sent: 08 April 2016 12:00
> To: fieldtrip at science.ru.nl
> Subject: fieldtrip Digest, Vol 65, Issue 7
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> Today's Topics:
> 
>   1. Re: FEM using Simbio (Johannes Vorwerk)
>   2. Re: FEM using Simbio (Cristiano Micheli)
>   3. Dipole fitting (Giovanni Pellegrino)
>   4. Birmingham-Illinois BRIDGE Fellowships (Ole Jensen)
>   5. Using FieldTrip to analyse LFP recordings in rat
>      (laetitia.lalla at inserm.fr)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Thu, 7 Apr 2016 14:25:42 +0200
> From: Johannes Vorwerk <j.vorwerk at uni-muenster.de>
> To: FieldTrip discussion list <fieldtrip at science.ru.nl>
> Subject: Re: [FieldTrip] FEM using Simbio
> Message-ID: <435735E3-7D87-4DD6-A2C1-E2BBFBBF4B44 at googlemail.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Hi,
> 
> this question was already answered in this thread
> 
> http://mailman.science.ru.nl/pipermail/fieldtrip/2016-March/010274.html <http://mailman.science.ru.nl/pipermail/fieldtrip/2016-March/010274.html>
> 
> If ft_volumereslice is not applied before the mesh generation, the afterwards applied transformation might flip the directions of the mesh, leading to the described error.
> 
> Best,
>        Johannes
> 
>> Am 06.04.2016 um 16:03 schrieb Carsten Wolters <carsten.wolters at uni-muenster.de>:
>> 
>> Dear Rajat,
>> 
>> the element-node cards of SimBio-NeuroFEM need to follow certain orientations (see www.simbio.de <http://www.simbio.de/>).
>> 
>> If you do not want to struggle with meshing/ordering, use the SimBio-VGRID mesher
>> http://vgrid.simbio.de/ <http://vgrid.simbio.de/>
>> that follows the required ordering of nodes. You might use this mesher to produce 1mm geometry-adapted FEM meshes
>> that show good overall performance, see
>> http://www.sci.utah.edu/~wolters/PaperWolters/2007/WoltersEtAl_IEEE_TBME_2007.pdf <http://www.sci.utah.edu/~wolters/PaperWolters/2007/WoltersEtAl_IEEE_TBME_2007.pdf>
>> and
>> http://www.sci.utah.edu/~wolters/PaperWolters/2016/WagnerLuckaVorwerkHerrmannNolteBurgerWolters_NeuroImage_2016.pdf <http://www.sci.utah.edu/~wolters/PaperWolters/2016/WagnerLuckaVorwerkHerrmannNolteBurgerWolters_NeuroImage_2016.pdf>
>> (latter was just accepted by NeuroImage).
>> 
>> Best regards
>>      Carsten
>> 
>> Am 06.04.2016 um 15:10 schrieb Rajat Thomas:
>>> Dear all,
>>> 
>>> Has anyone used the FEM approach to Headmodels using Simbio recently?
>>> 
>>> If so, I get this error:
>>> "Elements have wrong orientation or are degenerated"
>>> 
>>> Any ideas?
>>> 
>>> cfg        = [];
>>> cfg.method ='simbio';
>>> cfg.conductivity = [0.33 0.14 1.79 0.01 0.43];   % order follows mesh.tissyelabel
>>> vol        = ft_prepare_headmodel(cfg, mesh);
>>> 
>>> And;
>>> ?
>>> disp(mesh)
>>>            hex: [545883x8 double]
>>>            pnt: [569722x3 double]
>>>         labels: [545883x1 double]
>>>         tissue: [545883x1 double]
>>>    tissuelabel: {'csf'  'gray'  'scalp'  'skull'  'white'}
>>>           unit: 'mm'
>>>            cfg: [1x1 struct]
>>> 
>>> Any help would be highly appreciated.
>>> 
>>> Rajat
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> Rajat Mani Thomas
>>> Social Brain Lab
>>> Netherlands Institute for Neuroscience
>>> Amsterdam
>>> 
>>> 
>>> _______________________________________________
>>> fieldtrip mailing list
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>>> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip <http://mailman.science.ru.nl/mailman/listinfo/fieldtrip>
>> <carsten_wolters.vcf>_______________________________________________
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> ------------------------------
> 
> Message: 2
> Date: Thu, 7 Apr 2016 17:36:37 +0200
> From: Cristiano Micheli <michelic72 at gmail.com>
> To: FieldTrip discussion list <fieldtrip at science.ru.nl>
> Subject: Re: [FieldTrip] FEM using Simbio
> Message-ID:
>        <CADW7XCAQONsZ_ujPhkffskZ+j-mnHnAzunS68CdKU6MLSosUPA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Hi Rajat
> 
> My guess is that the orientations of your hexahedrons are not correct.
> According to a low-level file's internal rules, elements' orientations have
> to abide strict rules (not sure what exactly the contraints are in this
> case though...).
> I had same problems when for example the triangular boundaries used to
> define the 3d hexahedral mesh were not topologically correct, to start with.
> Admittedly this approach requires a lot of technical expertise.
> Can I ask you what do you need a FEM model for?
> 
> Regards
> Cris Micheli
> 
> 
> 
> 
> On Wed, Apr 6, 2016 at 3:10 PM, Rajat Thomas <r.thomas at nin.knaw.nl> wrote:
> 
>> Dear all,
>> 
>> 
>> Has anyone used the FEM approach to Headmodels using Simbio recently?
>> 
>> 
>> If so, I get this error:
>> "Elements have wrong orientation or are degenerated"
>> 
>> Any ideas?
>> 
>> cfg        = [];
>> 
>> cfg.method ='simbio';
>> 
>> cfg.conductivity = [0.33 0.14 1.79 0.01 0.43];   % order follows
>> mesh.tissyelabel
>> 
>> vol        = ft_prepare_headmodel(cfg, mesh);
>> 
>> 
>> And;
>> 
>> ?
>> disp(mesh)
>>            hex: [545883x8 double]
>>            pnt: [569722x3 double]
>>         labels: [545883x1 double]
>>         tissue: [545883x1 double]
>>    tissuelabel: {'csf'  'gray'  'scalp'  'skull'  'white'}
>>           unit: 'mm'
>>            cfg: [1x1 struct]
>> 
>> 
>> Any help would be highly appreciated.
>> 
>> Rajat
>> 
>> 
>> 
>> 
>> 
>> 
>> Rajat Mani Thomas
>> Social Brain Lab
>> Netherlands Institute for Neuroscience
>> Amsterdam
>> 
>> _______________________________________________
>> fieldtrip mailing list
>> fieldtrip at donders.ru.nl
>> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
>> 
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> ------------------------------
> 
> Message: 3
> Date: Thu, 7 Apr 2016 15:02:05 -0400
> From: Giovanni Pellegrino <giovannipellegrino at gmail.com>
> To: fieldtrip at science.ru.nl
> Subject: [FieldTrip] Dipole fitting
> Message-ID:
>        <CAN6FyLVw=e7gOOvGDo47fT3j0frr8FUAEcsm55O8ZzqA=u8GDw at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Dear Fieldtrippers,
> 
> Do you know if the FieldTrip Dipole Fitting has been compared to the CTF,
> Elekta, BESA or Curry? Are you aware of any study on this topic?
> 
> Thanks in advance for your help
> 
> Giovanni
> 
> --
> Giovanni Pellegrino, MD
> Multimodal Functional Imaging Laboratory
> Montreal Neurological Institute, McGill University
> Address: 332 Duff Medical Building, 3775 rue University, Montreal, QC, H3A
> 2B4, Canada
> Phone: (514) 398?1678
> Fax: (514) 398?7461
> Email: giovannipellegrino at gmail.com, giovanni.pellegrino2 at mcgill.ca
> Homepage: http://www.bic.mni.mcgill.ca/ResearchLabsMFIL/PeopleGiovanni
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> ------------------------------
> 
> Message: 4
> Date: Fri, 8 Apr 2016 09:23:46 +0200
> From: Ole Jensen <ole.jensen at donders.ru.nl>
> To: fieldtrip at science.ru.nl
> Subject: [FieldTrip] Birmingham-Illinois BRIDGE Fellowships
> Message-ID: <57075C82.8030309 at donders.ru.nl>
> Content-Type: text/plain; charset=utf-8; format=flowed
> 
> Dear all,
> 
> I would like to point you to a set of Birmingham-Illinois BRIDGE
> Fellowships providing some exciting research and career prospects:
> http://www.birminghamillinoisbridge.org/index.php/fellows/
> 
> In particular the areas 'Cognition and Ageing' and 'Brain Trauma' could
> be relevant for candidates with EEG/MEG expertise.
> 
> All the best,
> 
> Ole
> 
> --
> Prof. dr. Ole Jensen
> http://www.neuosc.com
> 
> 
> 
> ------------------------------
> 
> Message: 5
> Date: Fri, 08 Apr 2016 10:27:58 +0200
> From: laetitia.lalla at inserm.fr
> To: fieldtrip at science.ru.nl
> Subject: [FieldTrip] Using FieldTrip to analyse LFP recordings in rat
> Message-ID: <628babdc107aebd4cc7588ea87ce5ea6 at inserm.fr>
> Content-Type: text/plain; charset="utf-8"
> 
> 
> 
> Hello everyone,
> 
> my name is Laetitia and I'm a Phd student in Marseille (France). I'm
> doing in-vivo recording in freely-moving rats : I implant them with 2
> electrodes deep into 2 different regions of the brain. I'm studying the
> Local Field Potentials and I want to use FieldTrip to analyse the data.
> 
> To simplify :
> 
> - I have 2 rats.
> 
> - Each rat did 20 sessions of the task (on 20 different days).
> 
> - Each session consists of 20 trials of condition 1 and 20 trials of
> condition 2.
> 
> I have 2 questions.
> 
> 1) I have the feeling it would be meaningless to do "source
> reconstruction" because my electrodes are already deep inside my
> "source" and the LFP I am recording is very local. (My electrodes have
> 32 channels separated by 20-200 ?m. The LFP is very very similar across
> all the channels, so I averaged over the 32 channels to have one signal
> for each region.)
> 
> However, I see that 2 different functions exist for the statistics :
> FT_FREQSTATISTICS AND FT_SOURCESTATISTICS. So far, I've been using
> ft_freqstatistics but I encounter some issues (for exemple, doing
> monte-carlo permutation test to assess the imaginary coherence). I
> thought of computing it manually, but I'm thinking that maybe more stuff
> are implemented in ft_sourcestatisctics ?
> 
> ? Are these 2 functions fundamentally different or do they call the same
> sub-fonctions (and my problem has actually nothing to do with that) ?
> 
> 2) I'm a bit confused with the vocabulary from EEG and MEG studies (I'm
> not used to it yet...). From what I understood, in human studies, you
> can do comparison for a single subject (across trials) or across
> subjects. But I have 3 levels of comparisons in my design :
> 
> - WITHIN A SESSION, I WANT TO COMPARE ACROSS TRIALS (the 20 trials of
> condition 1 VS the 20 trials of condition 2).
> 
> - WITHIN A RAT, I WANT TO COMPARE ACROSS SESSIONS (between the 2
> conditions)
> 
> - then - in the very end - ACROSS RATS. But I have only 2 rats so far,
> so I will deal with this later.
> 
> I'm a bit confused when reading the tutorials and the mailing list,
> especially when it comes to the statistics... For example : this is from
> an email from 2013 by Eric Maris about "Nonparametric statistical
> testing of phase coherence"
> (http://mailman.science.ru.nl/pipermail/fieldtrip/2013-April/006401.html)
> "To compare coherence between conditions across subjects (instead of
> trials), you need a different statfun: depsamplesT (for a
> within-subjects design; subjects have participated in all conditions) or
> indepsamplesT (for a between-subjects design; subjects have participated
> in only one condition)."
> 
> ? If I want to compare across sessions (for a same rat), can I actually
> consider that my different sessions are "subjects"? And then compare
> coherence "across subjects" would be doing it "across sessions" ? And I
> would be in a "within-subject design" since my sessions involve the 2
> conditions every time ?
> 
> I realise that it may be very confusing... I hope you will understand my
> problem !
> 
> And if anyone already applied fieldtrip functions to do statistics on a
> different framework that the usual EEG/MEG, please let me know !
> 
> Thanks a lot,
> 
> Laetitia Lalla
> 
> PhD Student in Neuroscience
> 
> INMED, Marseille, France
> 
> 
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