Neuroimaging

Neuroimaging

  • Bernd Schmeikal added an answer:
    What are the advantages and what are the problems of the hypothesis about “retinoid system”?
    Is the hypothesis about “retinoid system” (by Professor Arnold Trehub), as described in “Consciousness and Cognition” 16 (2007) 310–330 and in the other works of Professor Trehub, a plausible hypothesis? What are its advantages and what are its problems?

    Professor Trehub describes it in the following words:
    “Activation of the brainʼs putative retinoid system has been proposed as the
    neuronal substrate for our basic sense of being centered within a volumetric
    surround –- our minimal phenomenal consciousness (Trehub 2007). Here, the
    assumed properties of the self-locus within the retinoid model are shown to
    explain recent experimental findings relating to the out-of-body-experience. In
    addition, selective excursion of the heuristic self-locus is able to explain many
    important functions of consciousness, including the effective internal
    representation of a 3D space on the basis of 2D perspective depictions. Our
    sense of self-agency is shown to be a natural product of the role of the heuristic self-locus in the retinoid mechanism.” (Abstract, from: Where am I? Redux.)

    For the publications of Professor Trehub see:
    https://www.researchgate.net/profile/Arnold_Trehub

    The question has been already discussed on the folowing thread:
    https://www.researchgate.net/post/Is_mathematics_a_human_contrivance_or_is_it_innate_to_nature
    Bernd Schmeikal · University of Vienna

    шапка невидимка - now I see better ... very good

  • Roya Kheyrkhah added an answer:
    Are there any EEG data from 7-12 years old children that are perfect and don't have any specific seizures and where can I find them?

    The most of data are related to disorders and disabilities, i want the perfect one of them. can any one help me? thanks.

    Roya Kheyrkhah · University of Tehran

    Thanks a lot  Mr Khatibi for your attention and guidance, I'm going to check it.

  • Kevin R. Urstadt added an answer:
    Has anyone seen CLARITY tissue clearing with no electrophoresis?
    I just posted this in the CLARITY resource center forum, but posting it here too. We found this hydrogel perfused/embedded right hemisphere of a rat cortex to be nearly completely clear after sitting in clearing solution in 37 degree incubator for ~5 weeks completely unattended. Next to zero tissue damage and it looks by far better than any brain that we have run through our ETC chamber. Has anyone else seen this?

    https://docs.google.com/file/d/0B9rk7EERI_okX3ZzUlc5VHBBTVk/edit?pli=1
    Kevin R. Urstadt · University of Michigan

    The Clarity Wiki implies that omission of bis-acrylamide (using only acrylamide) in the hydrogel polymerization process allows the tissue to be more porous. Perhaps that hastens clearing time?
    http://wiki.claritytechniques.org/index.php/Solutions#Changes_to_the_hydrogel_solution_composition
    http://wiki.claritytechniques.org/index.php/Passive_Clearing#Strategies_to_increase_clearing_speed

    Yang et al. (Cell, 2014) did this acrylamide-only hydrogel prep for tissue that had been pre-fixed, and their brains were cleared in substantially less time, on the order of days instead of weeks. They did use a little more SDS in their clearing solution, however (8% instead of the original protocol's 4%).
    Link to extended PDF: http://www.cell.com/cell/pdfExtended/S0092-8674(14)00931-3

    Additionally, Poguzhelskaya et al. (Molecular Neurodegeneration, 2014) did this in 1-1.5 mm thick coronal mouse brain sections as Annabelle had mentioned, having first perfused mice with the hydrogel solution. Their clearance time was 7-10 days.
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049387/

    I'm also just starting this passive clearing approach, so I'm only beginning to try these approaches. Best of luck to those also starting up this useful technique in their labs.

  • Xiao-Song He added an answer:
    Is FWE correction too conservative for whole-brain analyses?
    I'm doing a whole brain analysis on my dataset in SPM. There is hardly any result left after the FWE correction. I found a couple of papers that conducted the whole-brain analysis reported either FWE uncorrected results or just indicated regions reached significance (p<0.001, uncorrected) didn't survive FWE correction. However, for those studies doing ROI analyses, most reported positive result after FWE correction. So if FWE correction is too conservative for whole-brain analyses but not for ROI analyses?
    Xiao-Song He · Thomas Jefferson University

    Pretty nice discussion! Thank you all! 

  • Martin Pyka added an answer:
    Can anybody share raw-data of the rat-hippocampus obtained with the CLARITY-method with me?

    For a computational model of the rat-hippocampus I would like to better understand how the projections from the entorhinal cortex to the hippocampus looks like. I think, data obtained with CLARITY-method would be the best for my needs. Does anybody have volumetric data of the rat hippocampus and adjacent regions that he could share with me?

    Martin Pyka · Ruhr-Universität Bochum

    Sorry, but I don't get it. Where can I find the data?

  • Jean François Foncin added an answer:
    What are the causes of negative CSF cytology in the presence of ependymal metastases for a case hypothalamic germinoma?

    Any further role for the radiologist in this case?

    Jean François Foncin · Ecole Pratique des Hautes Etudes

    I agree with Muhammad Shoaib Akhtar. Standard CSF cytology methods, using routine centrifugation followed by resuspension are often not useful for CSF tumor cell cytology. Even "cytocentrifugation", directly on a slide or coverslip, alters cytological features. I used, for critical diagnostic CSF cytology, a sedimentation method developed a long time ago by Prof. Suta (Praha university), followed by May-Grunewald-Giemsa staining. Even so, speed is of the essence: twenty minutes between CSF sampling and lab technique are a maximum. Preliminary results were given in : SUBERO A., FONCIN J.-F., LE BEAU J. : Diagnostic cytologique du liquide céphalo-rachidien par la chambre de sédimentation de Suta. Neurochirurgie (Paris) 1968 14 n°5, 627-634.

  • Dorian Pustina added an answer:
    Does anyone know of an brain atlas of arterial territories that is registered to MNI or talaraich or some common space?

    I need a file that I can download use for data analysis (basically automatically determining what vascular distribution a stroke has occurred in).

    Dorian Pustina · University of Pennsylvania

    Same here, would be really interested to have a probabilistic digital atlas of territories. Will look at the papers Pascal and Christian suggested, but if someone has a link to a probabilistic blood supply map, that would be awesome.

    Dorian

  • Bernd Merkel added an answer:
    I'm looking for a journal in Neuroimaging which explicitly allows 2 senior co-authors. Any suggestions/ideas ?

    Usually a paper has one last (=senior) author. In my case, I have 2 senior (last) co-authors. Is there a paper that explicitly makes this visible ?

    Bernd Merkel · University of Melbourne

    Thanks Rebecca !

  • Ali Gordjinejad added an answer:
    JMRUI software
    I am planning to run some metabolic analysis with JMRUI software (for magnetic resonance spectroscopy) and I find it hard to analyse the data with it (finding an appropiate tutorial etc). Did somebody use it and could give me some support?
    Ali Gordjinejad · Forschungszentrum Jülich

    Dear all,

    I have a question regarding loading CSI files with jMRUI:  I tried to load the files as .IMA  but it doesn't work. I thought it would maybe work if I save my data on the Trio Siemens scanner as spectroscopy DICOM files. But it still doesn't work? I tried on jMRUI: Siemens Raw Data (NUM 4), DICOM,.......it just reports: "mrui.plugin.conversion:  Invalid Siemens Raw Data files: incorrect header."  Can anybody help me?  Thanks. 

  • Mohammad Javad Amoshahy added an answer:
    Can anyone suggest a MRI images database of a brain tumor with ground truth?
    I want to evaluate the efficiency of a MRI segmentation method. To do so, I need a database of MRI images of the brain with tumors (glioblastoma or any other type of tumors), but with a Ground truth (GT). Most of the time, the GT corresponds to manual segmentation done by a radiologist.

    I have found an alternative solution : the use of synthetic ground truth. Some formulas are given in this article :
    Synthetic ground truth for validation of brain tumor MRI segmentation http://www.ncbi.nlm.nih.gov/pubmed/16685825 but I don't have the code source and the article is not very well detailed.

    As attachment, an example of a ground truth (green) segmentation done by a physicist.
    Mohammad Javad Amoshahy · Sahand University of Technology

    Please give a download link for best  MRI images database  of a brain tumor with ground truth.

  • Chanukya Krishna Chama added an answer:
    What is the easiest/fastest way to convert nifti files to img/hdr?
    -
    Chanukya Krishna Chama · IIT Kharagpur

    I find following tools for easiest/fastest conversion

    http://imagej.nih.gov/ij/   <-- ImageJ

    (or) 

    http://fiji.sc/Fiji  <-- Fiji (ImageJ2)

  • Darren Jian Sheng Yeo added an answer:
    In resting-state fMRI analysis, is the cerebellum removed?

    I am doing a seed-based correlation analysis, and would be including the time courses from white matter, ventricles, global signal, and motion parameters as regressors. Is the cerebellum usually removed for such analyses?

    I would also like to clarify if a whole brain mask including the cerebellum is used to derive the global signal.

    Thanks!

    Darren Jian Sheng Yeo · Vanderbilt University

    Thank you so much for all the advice, Dr. Cocozza, Dr. Hernandez-Castillo, and Dr. Ashtari! Thanks for the paper too, Dr. Di! Yes, I gathered that I should not remove the cerebellum in my analysis. That question came up because the removal of cerebellum was part of a segmentation procedure, and I realized that I can also define the white matter and ventricles without using the segmentation procedure.

    I am still undecided about including global signal regression though.

  • Maria Carmen Martín-Buro added an answer:
    Are the images of faces problematic stimuli in neuroimaging?

    In a memory experiment, what is preferable to use: images of faces or objects? Some people say that faces are problematic because they are relevant stimuli that are not processed like the rest of stimuli and it could introduce non-memory-related  activations in neuroimaging data. We are not interested in exploring emotion or social cognition. 

    Maria Carmen Martín-Buro · Universidad Politécnica de Madrid

    I wasn't sure but now with these references and your experience I've decided not to use faces. Thank you!

  • Dorian Pustina added an answer:
    How do you do high-level tractography?

    I'm looking to perform tractography with high resolution DTI data; at 64 gradient directions, voxel sizes of 2x2x2, b-value = 1500, 3T images.

    I've been reading around and found that the fODF (like CSD based, Jeurissen et al., 2011) algorithms could be an improvement over the dODFs (DSI and q-ball) and of course over the tensor-based algorithms, but there are still so many different fODF algorithms and I would like to know how to choose one or two.

    I'm also interested in quantification of the streamlines from tractography, and I would like to know which are the most useful metrics derived from tractography (i.e. fiber leght, number of fibers, etc), and if a reliable way to obtain such measurements exists.

    Dorian Pustina · University of Pennsylvania

    In my opinion the best software for tractography now is a combination ExploreDTI/MRtrix, using CSD and probabilistic algorithm. As you mentioned yourself, ExploreDTI does not offer great probabilistic algorithms, yet is the software I use to manage the preprocessing, MRtrix cannot do preprocessing at all. Using them in combination with HARDI, I have been able to obtain difficult tracts such as the optic radiations, also getting similar results to dissection studies and other tractography papers. So ExploreDTI could be the best preprocessing software, MRtrix the best CSD tractography software.

    StarTrack did not yield good  tractography for me, streamlines were more noisy with more erroneous directions. This is despite using HARDI. But I think Flavio was working on integrating a probabilistic algorithm as this option was greyed out when I used it.

    Good luck.

  • James Bjork added an answer:
    What do negative beta weights in ROI analyses mean?

    Hi all,

    I am currently analysing data from an fMRI study, with a 2x2 between-within design. Patients vs controls reflect the between factor, and congruent and incongruent trials reflect the within factor (this is a Stroop task).

    After seeing an interaction effect between the two factors in several brain clusters, I wanted to extract the beta-weights from these clusters to explore the underlying effects.

    I used Marsbar to extract the raw beta-weights from congruent and incongruent trials, separately (so no contrast between conditions performed), and plotted the results for my two groups.

    Many of the resulting beta-weights are negative, and I wonder what this means? Does it reflect a sort of 'deactivation'?  

    Any input will be highly appreciated!

    James Bjork · Virginia Commonwealth University

    I always do a VOI analysis of a contrast-activated voxel, to characterize what is driving the A-B contrast.  Is it that there is activation during event A or deactivation during B, or some combination of the two?  Because I use event-related designs with trials every several seconds, I can use AFNI with mapfiles that enable trial-averaged dumpouts of the whole hemodynamic response averaged across all trials of that type (c.f. PMID 18672069 ).  That gives a graphical answer right there.  IMO one shouldn't just plug and chug contrasts using turnkey software without knowing what's going on in the trial-type-averaged BOLD signal volume by volume.

  • Helen Macpherson added an answer:
    Can someone suggest a good, short duration fMRI activation task?
    I am looking for a good fMRI task which shows strong activation, but is approximately 6 minutes or less in duration. This task is to be used with older people. A memory paradigm would be preferable, but suggestions for attentional tasks would also be helpful.
    Helen Macpherson · Swinburne University of Technology

    Thank you for all your suggestions, we ended up going with the freely available n-back task from the Human Connectome Project. 

  • Jared P Dempsey added an answer:
    Can anyone point me to an article(s) that specifically studies the influence of methodological/analytic choice in neuroimaging?

    Can anyone point me to an article(s) that specifically studies the influence of methodological/analytic choice in neuroimaging?  The rational and science behind neutral cue subtraction seems justified for the majority of physiological and neuroimaging studies.  However, when it comes to the frontal lobe, I'm not convinced that neutral cue subtraction is appropriate.  Of course, baseline correction is critical.  However, if passive viewing of geometric shapes elicit change in the PFC, why would we want to subtract a neutral cue?  Consider the variety of stimuli in IAPS neutral cues (books, household objects, etc).  These items will likely produce unique results in the PFC.  Any pub recommendations or thoughts would be greatly appreciated.

    Jared P Dempsey · Addiction Recovery Research Institute (Lubbock, TX)

    Thanks, all.  I ended up conducting analyses both ways.  Hopefully someone will specifically investigate the neutral cue impact soon.  Some food for thought:

    -Neutral cue response is modulated during pharmacological treatment

    Outhred T, Das P, Felmingham KL, Bryant RA, Nathan PJ, Malhi GS, Kemp AH. Impact of acute administration of escitalopram on the processing of emotional and neutral images: a randomized crossover fMRI study of healthy women. Journal Of Psychiatry & Neuroscience: JPN 2014;39 (4), 267-275.

  • Ivan Bodis-Wollner added an answer:
    Any suggestions on neuroimaging of oculomotor cognitive control tasks? I want something similar to antisaccade task, like IOR maybe?

    The antisaccade task has been a well-studied paradigm to assess executive functioning. People are asked to look in the opposite direction of a salient peripheral stimulus. I am wondering if there are similar tasks out there that use eye movements, other than the antisaccade task, to measure executive functioning or cognitive control. Inhibition of return (IOR) could be similar to the antisaccade task and there is also the gap effect. Any suggestions on particular paradigms or authors would be a huge help. Thanks!

    Ivan Bodis-Wollner · State University of New York Downstate Medical Center

    Voluntary saccades to imagined target features in complete darkness. There are some fMRI studies on saccades in the dark .. worth reviewing them, but the one I am bringing to your attention has not been explored to the best of my knowledge

  • Bruno Costa added an answer:
    Can anyone advise me in search of software for EEG sources?
    I'm doing source analysis. Does anyone know a software for source analysis like FD VARETA?
    Bruno Costa · Federal University of Rio de Janeiro

    Does any one know if it is possible to do the Anova estatistics on the software sLORETA? I think the software doesn`t have this option but some articles say that they did it as the file here.

  • Gioele Santucci added an answer:
    What is the definition of the intensity time curves for perfusion MRI Data?

    What is the definition of the intensity time curves for perfusion MRI Data?

    Gioele Santucci · University of Bologna

    For Example, when you are studing brain tumors and you use a DCE- T2*Weighted imagind SSH, it is better to use a preinjection of 2cc of intravenous paramagnetic contrast and waiting period of 8-10 minutes: this is usefull for having an intensity time curve with a more  accurate subtraction and provides information about the function of the blood-brain barrier. 

  • Kevin Mandrick added an answer:
    Non-contact EEG sensors
    I need some practical suggestions for designing a data acquisition subsystem to a BCI.
    I am interested in sensors that do not require contact with the brain.
    I've read something about Photrodes. Are there other options?
    Kevin Mandrick · Institut Supérieur de l'Aéronautique et de l'Espace (ISAE)

    There is a few solutions on the market for non-invasive optical brain imaging (fNIRS devices). Personnaly, I could suggest one. It exists some companies like Rogue, Artenis, Shimadzu, Hamamatsu, Nirx, Techen, Gowerlabs, Hitachi, Cortech, ISS, Hemophotonics, MRRA just to cite commercial entities...

  • Esat Adiguzel added an answer:
    Can anyone help with a problem with extracting hippocampal volume using VBM and WFU-pickatlas?

    Hi,

    Sorry I am new to VBM and I want to compare hippocampous volume by using two different method (manual tracing and atlas-based method ) .I have two kind of samples patient with MTLE and normal ones. I used a script “ get_totals.m” by Ged Ridgway and WFU-pickatlas but the results were odd and very small. There is also an article “ Age-related changes in regional brain volume evaluated by atlas-based method “ Wataru Gonoi 2010 springer , that used nearly the same method using WFU-pickatlas and SPM5.
    I checked SPM mail archive there were same titles but unfortunately I got confused there were no clear answers and now I am not sure whether this method is correct and reliable .


    I would be very appreciated if anyone could help me.

    Best regard


    Mahsa,

    Esat Adiguzel · Pamukkale University

    I understand that you need to check the reliability of software. You can use stereological methods to measure real volumes. But you should have the thickness of the MRI slices. After this procedure, same volume should be measured using by the software. I can send you the references and more knowledge about stereological methods. adiguzel@pau.edu.tr

  • Leonard F Koziol added an answer:
    Are there any white matter (WM) tracts that can be implicated to affect sexual functioning in patients with MTBI?

    Alteration of sexual functioning in patients with traumatic brain injury is a phenomenon that has been widely studied. However, these studies are predominantly limited to self reported symptoms and hypothalamic-pituitary dysfunction (assessed through hormonal workouts mostly. Detailed imaging studies of this phenomenon are extremely scarce, if not unheard of.

    What are your thoughts on possible influence of deep white matter tracts on sexual functioning in TBI, and MTBI specifically?

    ON THE RIGHT TRACK? LET ME SAY A FEW THINGS. I AM NOT AN EXPERT IS THE AREA OF SEXUAL FUNCTIONING. I AM IN THE CLINICAL FIELD, AND I TRY TO APPLY BRAIN NETWORK DATA WITH CLINICAL DATA. SO, I WILL ATTACH ONE MORE PAPER. ALTHOUGH IT IS ABOUT ADHD, IT IS REALLY ABOUT THE IDENTIFICATION AND FUNCTIONS OF LARGE SCALE BRAIN SYSTEMS. THE PAPER IS APPLICABLE TO ANY DISORDER/SYMPTOM; THE CHALLENGE IS TO VIEW THE PREVIOUSLY ATTACHED PAPER, ALONG WITH YOUR IDEAS, WITHIN THE CONTEXT OF THESE LARGE SCALE BRAIN SYSTEMS. DRS. WANG, BUCKNER, AND IUE HAVE TOGETHER RECENTLY PUBLISHED ADDITIONAL PAPERS ABOUT HOW THESE BRAIN NETWORKS ARE PREFERENTIALLY CONNECTED WITHIN THE LEFT AND RIGHT HEMISPHERES OF THE CORTEX AND WITHIN THE CONTRALATERAL HEMISPHERES OF THE CEREBELLUM. TAKEN TOGETHER, COMBININHG THIS INFORMATION, SHOULD PUT YOU WELL ON YOUR WAY TO FINDING LIKELY ANSWERS TO YOUR QUESTIONS. THE OTHER AUTHORS ARE MEMBERS OF RESEARCH GATE. - LK

  • Irina G Makarenko added an answer:
    Problems with long storage of brain material in 4% paraformaldehyde
    After long storage of brain material with DiI insertions in 4% PAF, some tissue looks very good, but several specimens are covered by white crystals on the surface and inside the tissue.

    After cutting on the vibratome the last ones do not provide good pictures. Do you know if it is possible to restore such material? How to do this?
    Irina G Makarenko · Russian Academy of Sciences

    Thanks for your answer. Evrything is clear.  But it looks strange that I newer read about formaldehyde as a fixator for the DiI tracing!

    Long storage is a result of our Russian specificity : when I had grant and animals (rats) I worked on the fetuses. Sometimes they were very numerous and I prepared not only planned material but some additional training applications according my ideas.  Later if I had students I gave them this material or use it myself.  So sometimes storage was rather long.  Really I prefere long stroage for the developmental studies, because in this case I am sure that the absence of studied connections is not the result of short exposition. Additionally dendritic tree is better

    Yes we have fluorescent and confocal microscopes with such filters, but now I have no my own grant and do not perform new experiments as I have previously prepared material.   Additionally I am not sure that it will be possible to send a chemical reagent to Russia although it is interesting to try....    You mention that DiD is better - what is the difference with DiI

  • Olaf Dietrich added an answer:
    How much SNR difference can we expect for brain imaging if we compare a Philips Ingenia 70 cm bore to a Siemens Prisma 60 cm bore?

    I realize the 60 cm is better in general, but I wonder if the Ingenia would reduce this difference somewhat?  We're compromising needs for extremity/MRS users and brain/MRI users.  At the same time we don't want to sacrifice the quality of the fMRI studies.  What data is available to help us motivate our decision?

  • Ekaterina V. Pechenkova added an answer:
    Does anyone have experience with fMRI on Siemens Spectra (3T) or Siemens Aera (1.5T)?

    It maybe looks like a strange question, because none of these scanners is probably your system of choice for neuroimaging research, but I would appreciate any sharing of experience.

    Ekaterina V. Pechenkova · Institute of Practical Psychology and Psychoanalysis

    Thank you! Yes, I would prefer Trio as well :) So far it seems to be the best research scanner. But other Siemens scanners can be used for fMRI as well.

  • Kenneth Sung Lai Yuen added an answer:
    Can we bridge the Gap between stimuli space and activiy space using neuroimaging techniques?

    In brain decoding encoding methods we are dealing with features at the stimuli side (image, videos, etc.) these features includes shape,  color, texture etc. In the brain activity side we have for example fMRI time series data related to the some stimuli, and we extract features from this signals. The question is can we map between two types of aforementioned features?

    Kenneth Sung Lai Yuen · Universitätsmedizin der Johannes Gutenberg-Universität Mainz

    You could refer to the following two seminal papers that propose a method in attempted to map the two different spaces (perceptual vs stimulus):

    Kriegeskorte N, Mur M, Bandettini P (2008), “Representational similarity analysis - connecting the branches of systems neuroscience.” Front Syst Neurosci 2:4

    Kriegeskorte N, Mur M, Ruff DA, Kiani R, Bodurka J, Esteky H, Tanaka K, Bandettini PA (2008), “Matching categorical object representations in inferior temporal cortex of man and monkey.” Neuron 60(6):1126-41

    And in the lab of Jack Gallant they've done a lot to build forward models to predict individual's percept from moltivoxel fMRI BOLD signal:

    http://gallantlab.org/publications.html

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