[Freesurfer] Postdoctoral or experienced research position in a Neuroscience/Resilience/Twin Research Program

2018-08-28 Thread Yann Quidé
External Email - Use Caution Posted on behalf of Dr Justine Gatt. Dear Colleagues Our team is currently advertising a postdoc / experienced research assistant position in a neuroscience research program focusing on wellbeing and resilience in twins. Applications close

[Freesurfer] fsaverage for a Left vs Right hemisphere Longitudinal Comparison

2018-08-28 Thread Wang, Xiaoyu
External Email - Use Caution Hello Freesurfer Experts, I am trying to compare the left and right hemisphere of a group of PD patients with Mass-Univarate LME. >From what I can see in the wiki tutorial, the mris_preproc only assembles data >from one hemisphere at a time, which

Re: [Freesurfer] error opening file dlabel/mni/lh.atr_PP_avg33_mni_bbr_end1_dil.nii.gz

2018-08-28 Thread Yendiki, Anastasia
Hi Montse – In case you’re still having trouble with this subject, I would check the structural segmentation (aparc+aseg from recon-all) and see if there’s anything wrong in parts of the brain that the ATR goes through. If that looks fine, then sending along the entire trac-all.log file would

[Freesurfer] LME Univariate pvalue inconsistent

2018-08-28 Thread Wang, Xiaoyu
External Email - Use Caution Hello Freesurfer Developers, I'm attempting to use Univariate LME analysis to compare the symptomatic and asymptomatic hemispheres of early stage Parkinson's disease patients. I re-organized the data so that the symptomatic hemisphere is the left

Re: [Freesurfer] Question about Freeview, 20% threshold

2018-08-28 Thread Yendiki, Anastasia
The output of TRACULA is a probability distribution that tells you how likely each voxel is to be part of the tract that you’re looking at. Voxels with low probability values are not very likely to be part of the tract. Setting the threshold in freeview to 20% means that you only want to

Re: [Freesurfer] [TRACULA] eddy_correct /affine registration matrices / motion/ eddy currents

2018-08-28 Thread Yendiki, Anastasia
Hi Loic – In simple terms, motion will cause a rigid transformation of the brain (translation and rotation only), whereas eddy currents will add non-rigid effects (scaling/stretching). By registering each DWI to the first b=0 image, and then extracting the translation and rotation part of the

Re: [Freesurfer] TRACUAL eddy_correct Usage

2018-08-28 Thread Yendiki, Anastasia
Hi Tim – The best method to use will depend on the data you have. If you have very high b-values, you should use eddy. You can turn off the eddy current part of the preprocessing with “set eddy=0” in the config file, and run trac-all on your corrected images. Best, a.y From:

Re: [Freesurfer] questions about Tracula and doeddy=1 or 0

2018-08-28 Thread Yendiki, Anastasia
This is not entirely surprising. You have a b-value that’s quite high (b=3000) and eddy_correct will not work well with such high b-values, because is tries to register the b=3000 images to a b=0 image, and the b=3000 images do not have enough anatomical detail to be registered correctly. You