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ROAST: TES modeling made easy - Shared screen with speaker view
Panagiotis
09:04
time for this was changed or the GMT+1 is wrong ? Thank you in advance
Panagiotis
11:01
it was written 17:00 GMT+1
cgil
13:19
Hi this is Cristina, and I haven´t used yet
Giulia Mattavelli
13:56
Hi, I'm Giulia. My research group is using it, but I have not used it directly
Vikram
14:09
Hi, I'm Vikram Shenoy (Assoc. Research Scientist) at Kessler Foundation (New Jersey). I have used ROAST just once before for testing the modeling using individual MRI
Vikram
15:12
I am more interested in learning how to use ROAST for reporting in scientific writing. I have an ongoing project on HD-tDCS for stroke and TBI rehab.
Chun Hang Eden TI
16:42
hi I am Eden from Chinese University of Hong Kong. I have used ROAST once to generate head meshes. I am more interested to know more about using ROAST on MRI images with pathologies like stroke
Vikram
17:35
is the problem because of lesion mapping?
Holczer Adrienn
17:40
Hi, I'm Adri from the University of Szeged and I have not used ROAST before; however, I have tried other simulators (e.g. SimNIBS). I do research applying tDCS and tACS so I would be interested to model the effects of the montages I use.
Panagiotis
18:36
Hello thank you for the session. I haven't used it either. I would be interested to learn about applications in cognitive neuroscience, esp. top-down processes, cognitive control etc
tamas.foldi
19:58
csá
Weronika Potok
20:48
Hi I’m Weronika, I’ve used SimNIBS and haven’t used ROAST yet. I’m wondering if it is possible to simulate high frequency tES such as tRNS?
Lucas Parra
21:28
yes, i will be sure to discuss this later
Lucas Parra
21:53
or maybe now
Weronika Potok
23:35
Thank you
Giulia Mattavelli
29:53
is it possible to model montages with extracephalic electrodes?
Vikram
30:00
Can we use individualized electrode positions? digitized using 3D digitizer?
Chun Hang Eden TI
30:36
Can we used customized electrode location?
Samantha Booth
33:20
Can you use a template MRI if you don’t have the subject’s MRI?
Vikram
33:45
is that MNI coordinate system?
Ruben Perellón-Alfonso
34:05
What coordinate system is to be used?
mariacarla
35:39
is it possible to perform intra-cerebral stimulation simulations?
Gabriele
36:19
What about the size of the electrodes? Is it possible to define the area (cm2 or mm2) of electrodes?
Gaurav Bhalerao
38:19
we can specify current for the simulation but I dont think we can specify frequency of the current. so can I say that tDCS and tACS simulations for same electrode placement will give same output?
Nivethida
40:28
Following up with the above question, I read from a recent paper that for tACS delivered over two locations, the electric field distribution would be different depending on the relative phase of the 2 signals. How do we input that information?
yousef salimpour
40:39
what we should consider if we use the MRI imaging from the patient such as epilepsy with depth electrode?
Jenny Lee
41:28
does it matter if you have more than one current source? For example, if I use 2 different stimulators instead of one multichannel stimulator, to input current to >2 tDCS electrodes?
Ghazaleh Soleimani
46:02
How to transform electric field maps from native space to MNI space for group level analysis?
Sheida R
46:23
are pads always presumed to be rectangular?
Lénia Amaral
46:25
It takes in account if we are using gel or saline based electrodes?
Nick Davis
46:39
Hello. Can I have an arbitrary shape of electrode? e.g. an ellipse?
Lucas Parra
46:49
It was suggested that we wait with questions until Andy had time to show more material. I will bring them up at the end.
Ghazaleh Soleimani
47:34
Which one is better? Surface-based models or volume-based?
Setare Rezakhani
50:07
sorry i dont have any voice
Lucas Parra
51:30
non-uniformty under the electrode: yes
Alexis Harle
52:05
If there is a segmenting error when the program runs, is there a way to go back and fix it?
Yuranny Cabral
53:34
Is it possible to import a mesh created outside of ROAST? can manual corrections be done to the segmentations?
Jenny Lee
54:10
Thanks for the great talk Andy! I was wondering if you could talk about how to interpret the vector information produced by ROAST? For example to compare current direction between subjects? How could I tell which direction current is flowing in with respect to the cortical surface, just from looking at the numerical outputs in ‘ef_all’?
LS Gan
55:18
I often see warnings (not errors) about a list of nodes not found/exist when running ROAST, how worry should I be about that?
Fabiola Alonso
55:25
Regarding the conductivity, do you make any adjustment upon changes in frequency or temperature?
Samantha Booth
55:49
Sorry I didn’t quite catch what you said, is gel included by default, or do you add this in?
LS Gan
56:17
Thank you.
Alexis Harle
56:34
One example of an error we received was that the segmentation incorrectly perceived the eyes, which created holes in the skull.
Bryan Howell
56:39
(Came in tad late, sorry.) Could you provide an overview of numerical infrastructure -- FDM/FEM, default solver, etc.? Does user have control over these?
mariacarla
01:00:31
you mentioned empirically reliable conductivity values. do you refer to this study: Y. Huang, A. Liu, et al., Measurements and models of electric fields in the in vivo human brain during transcranial electric stimulation, eLife 2017;6:e18834 ?
Lucas Parra
01:01:38
yes, that is a good paper to read up on conductivityand validation
Lucas Parra
01:02:14
yes, gel is included by default
Jill
01:02:37
What kind of MRI scans would you recommend to use for the simulations? Especially in regard to possible segmentation errors (e.g. in some areas wrong bone segmentation). Would you recommend to use e.g. only one T1 MRI scan, T1 and T2 MRI scans or T1 with fat suppression?
Steven Beumer
01:02:40
A nice review paper on Electrical conductivity values in the brain is : Variation in Reported Human Head Tissue Electrical Conductivity Values by McCann et al. (The MREIT values are not MREIT), but for the rest it's a good overview paper
Lucas Parra
01:03:18
standard T1 used for brain imaging is good
Samantha Booth
01:03:28
sorry if i missed this, if we use a rubber electrode covered by a sponge, is this default or do we need to add the sponge?
Lucas Parra
01:03:40
T2 helps, but not really needed
Allen
01:03:44
What value do you recommend to do this prophylactic "zeropadding"
Lucas Parra
01:03:54
not sure about fat saturation
Lucas Parra
01:04:35
zeropadding, enough to fit the electrode.
fatemeh yavari
01:06:04
It would generate optimal montage out of which montages (regarding eilec size, shape, position, current, etc.)?
Vikram
01:06:08
Is there any way to simulate the electric field intensity as a function of time? e.g. At the beginning of the stimulation vs. 20 min. post stimulation?
Blair
01:06:28
Can you say a bit more about what the leadfield is and how roast_target uses it to find an optimal montage?
Giulia Mattavelli
01:06:41
I did'n understand if it gives you the best solution or you have to specify the number of electrodes.
Lucas Parra
01:06:43
there is no reason to expect that fields would change in time
Ghazaleh Soleimani
01:10:23
Does defacing of structural MRI affect electric field modeling?
Lucas Parra
01:10:29
yes
Lucas Parra
01:11:07
there are no secific studies that i am aware of how much it would change, but in theory it will have an effect.
Lucas Parra
01:11:18
its best to use the original MRI is possible.
Ghazaleh Soleimani
01:11:46
Thank you.
Lucas Parra
01:13:07
the "lead field" is the same lead field of EEG source localization, it relates currents on the electrode with fields generated in the brain, and vise versa, currents in the brian and voltages on the electrodes
Blair
01:13:47
thanks!
Lucas Parra
01:15:29
"it gives you the best solution or you have to specify the number of electrodes" ...when you optimize for intensity in a given target, you will always get the minumum number of electrodes possible.
Giulia Mattavelli
01:15:54
thanks!
Lucas Parra
01:15:55
when optimizing for focality, then you will get often as many electrodes as you are allowing it to use.
Lucas Parra
01:16:12
which is limited by your hardware.
Bryan Howell
01:17:19
Does ROAST give you control over shape and mapping order of elements?
Jen Chesters
01:17:20
Thanks so much, this was really helpful
Alexis Harle
01:17:30
Will we have access to the recording of this presentation?
Lucas Parra
01:18:05
yes, we will post on the ROAST website
Steven Beumer
01:18:17
Thank you for showing all features of ROAST. What are future additions to the program you would like to do?
mariacarla
01:19:12
infrastructure for lesion delineation?
Conor Minogue
01:19:18
thanks for great presentation
Alexis Harle
01:19:19
I know I mentioned this earlier, but is there a way to resolve segmentation issues (ie. Holes in the brain) if this problem arises
Desmond Agboada
01:19:32
that's a really GOOD long term plan!
Alexis Harle
01:19:40
Sounds good!
Ghazala Saleem
01:19:40
Is pediatric modeling possible?
Yuranny Cabral
01:19:41
Thanks for the great presentation
mariacarla
01:19:51
which is the infrastructure about lesion delineation?
Samantha Booth
01:19:51
do the parameters for the MRI acquisition matter? or can it handle anything. thanks for a great presentation!
Ssaleh
01:20:19
thanks for the session and all the useful information..
Lucas Parra
01:20:22
look for "MultiPrior" on pulbications are Parralab.org
Lucas Parra
01:20:45
that takes care of segmenting lesions
mariacarla
01:20:52
thanks!
Lucas Parra
01:20:53
we plan to incorporate into ROAST
Lukas Hirsch
01:20:56
I will be talking about the lesion segmentation on Wednesday's first session
Alexis Harle
01:20:58
Thank you!
Vikram
01:21:01
did you say Deepmedic or deepscan for lesion segmentation?
Vikram
01:21:27
thanks @Lukas Hirsch.. I look forward to attending your talk.
Lucas Parra
01:21:29
MultiPrior, or come to the presentaiton of Lukas Hirsch
Carlos Campos
01:21:57
Thank you so much for this presentation!
Weronika Potok
01:21:57
thank you
Vikram
01:21:58
thanks for the great presetnation :)
Bryan Howell
01:21:59
Thanks!
Samantha Booth
01:22:02
thanks!
Jenny Lee
01:22:05
Thank you! Great talk and great software
LS Gan
01:22:05
Thank you very much!
Anushree_Bose
01:22:07
Thank you!
Gabriele
01:22:07
Thank you very much!
Giulia Mattavelli
01:22:08
thanks
Steven Beumer
01:22:11
Thanks ! Great talk !
Ghazaleh Soleimani
01:22:17
Thanks!
exdi7491
01:22:25
Thank you for the informative presentation!
Ingrid
01:22:31
Thank you!
brealz
01:22:38
thanks!
Desmond Agboada
01:22:40
Great talk. thanks!
Allen
01:22:41
thanks