ynic-users June 2016

ynic-users@ynic.york.ac.uk

5 participants
9 discussions

by Gary Green

http://www.pnas.org/content/pnas/early/2016/06/27/1602413113.abstract.html?… Functional MRI (fMRI) is 25 years old, yet surprisingly its most common statistical methods have not been validated using real data. Here, we used resting-state fMRI data from 499 healthy controls to conduct 3 million task group analyses. Using this null data with different experimental designs, we estimate the incidence of significant results. In theory, we should find 5% false positives (for a significance threshold of 5%), but instead we found that the most common software packages for fMRI analysis (SPM, FSL, AFNI) can result in false-positive rates of up to 70%. These results question the validity of some 40,000 fMRI studies and may have a large impact on the interpretation of neuroimaging results. They state "Our principal finding is that the parametric statistical methods work well, if conservatively, for voxelwise inference, but not for clusterwise inference. We note that other authors have found RFT clusterwise inference to be invalid in certain settings under stationarity (21, 30) and nonstationarity (13, 33). This present work, however, is the most comprehensive to explore the typical parameters used in task fMRI for a variety of software tools. Our results are also corroborated by similar experiments for structural brain analysis (VBM) (11–13, 39, 40), showing that cluster-based P values are more sensitive to the statistical assumptions. For voxelwise inference, our results are consistent with a previous comparison between parametric and nonparametric methods for fMRI, showing that a nonparametric permutation test can result in more lenient statistical thresholds while offering precise control of false positives (13, 41). " Would be worth discussing at a ynic seminar later in the summer Gary -- --------------- Gary Green York Neuroimaging Centre & Centre for Hyperpolarisation in Magnetic Resonance The Biocentre York Science Park Innovation Way Heslington York YO10 5NY tel +44 (0) 1904 435349 fax +44 (0) 1904 435356 mobile +44 (0) 788 191 3004 http://www.ynic.york.ac.uk http://www.york.ac.uk/chym/ https://www.ynic.york.ac.uk/about-us/people/ggrg

8 years, 10 months

Fixing pesky file permission problems

by Andre Gouws

We are aware that many of you who use shared project folders often encounter the situation where a file in that folder is not accessible to all members of the group. We have prepared some guidance on how to avoid this happening. In addition, we have prepared a (semi) automated procedure that will any user with access to a group folder to reset the permissions in that folder so that all files can be shared by all users. This procedure involves running a script in a command terminal -- a script that resets the permissions in the entire group directory for all users. For information, please log into the YNiC wiki with your YNiC login and view the guidance at: https://www.ynic.york.ac.uk/docs/ITPages/FilePermissions -- André ************************************************************************ André Gouws York Neuroimaging Centre University of York The Biocentre York Science Park Heslington YO10 5NY Tel: +44 (0) 1904 435327 Fax: +44 (0) 1904 435356

8 years, 10 months

Biocentre fire alarm test

by Gary Green

Hi All, Apologies for the short notice; however, would you please be advised that following further changes to the fire alarm system within the Biocentre MRI Extension; it will be necessary for me to re-witness the system in operation on Wednesday 22nd June 2016 between the hours of 16.30pm & 18.30pm approximately. Due to the nature of the test being that the alarms will need to be activated; so to avoid anyone leaving the building, on each activation and it may need to be carried out on a number of occasions; the alarm will only sound for a short period of time (30 seconds approx). Although it is anticipated that a smooth operation of the above will be carried out successfully; should the alarm sound continuously for more than 1 minute, then all precautions need to be taken and all personnel should leave the building and go to their designated muster point. It is also assumed that these tests may at some point effect the Fire Alarm System in CHyM; although these will be alerts rather than full sounder activation; however, once again, should the alarms sound for more than 1 minute; the same will apply to the occupants of CHyM and all personnel should make their way out of the building as appropriate. In order to assist in making the end user / operatives aware, I will be affixing notices at the entrance doors of both the Biocentre and CHyM Buildings advising of this test on Wednesday afternoon (22/6/16). -- --------------- Gary Green York Neuroimaging Centre & Centre for Hyperpolarisation in Magnetic Resonance The Biocentre York Science Park Innovation Way Heslington York YO10 5NY tel +44 (0) 1904 435349 fax +44 (0) 1904 435356 mobile +44 (0) 788 191 3004 http://www.ynic.york.ac.uk http://www.york.ac.uk/chym/ https://www.ynic.york.ac.uk/about-us/people/ggrg

8 years, 11 months

Two seminars at YNiC this week

by Gary Green

There will be two ynic seminars this week. First we have an extra seminar by Andy Ioannides from the Lab for Human Brain Dynamiocs, Nicosia. This seminar will be at noon on Wednesday the 15th in BO20 and the title is "Understanding sleep and its implications for specific health conditions" the abstract is below The second seminar is at the normal time of 4pm on Thursday also in BO20 That seminar will be given by Jody Culham from Western and the title is "The treachery of images":Why the brain responds differently to real objects than photos " Her seminar abstract is "Psychologists and neuroimagers commonly study perceptual and cognitive processes using images because of the convenience and ease of experimental control they provide. However, real objects differ from pictures in many ways, including the availability and consistency of depth cues and the potential for interaction. Across a series of neuroimaging experiments, we have shown that the brain responds differently to real objects than pictures, both in terms of the level of activation and the pattern. Now that these results have shown quantitative and qualitative differences in the way the brain processes real objects and images, the next step is to determine which aspects of real objects drive these differences. " ----------------------------- Andy Ioannides abstract is "Some 20 years ago, Michel Jouvet, motivated by the early PET scanning studies of the sleeping brain wrote in the concluding chapter of his book The paradox of sleep - the story of dreaming “… the majority of researchers are waiting with bated breath for the results of studies combining PET scanning, ‘functional’ magnetic resonance imaging (fMRI), magnetoencephalography and tomographic electroencephalography.” The developments in the last two decades have fully vindicated this statement. The talk will first review published work obtained from real time tomographic analysis of the first whole night MEG recordings of sleep that focused on changes in regional brain activations and connectivity between areas related to eye movements and [1] and changes in regional spectral content in each sleep stage and especially during Rapid Eye Movement (REM) sleep [2]. The rest of the talk will present unpublished results from further and more detailed analysis of the same data. focusing on light sleep (NREM1 and NREM2) and discuss the new findings in the context of current ideas about the role of K-complexes and spindles in sleep maintenance and memory consolidation and how these may relate to pathology. " References: [1] Ioannides, A.A., Corsi-Cabrera, M., Fenwick, P.B.C., del Rio Portilla, Y., Laskaris, N.A., Khurshudyan, A., Theofilou, D., Shibata, T., Uchida, S., Nakabayashi, T., Kostopoulos, G.K., 2004. MEG tomography of human cortex and brainstem activity in waking and REM sleep saccades. Cereb. Cortex 14, 56–72. [2] Ioannides, A.A., Kostopoulos, G.K., Liu, L., Fenwick, P.B.C., 2009. MEG identifies dorsal medial brain activations during sleep. Neuroimage 44, 455–468. doi:10.1016/j.neuroimage.2008.09.030 -- --------------- Gary Green York Neuroimaging Centre & Centre for Hyperpolarisation in Magnetic Resonance The Biocentre York Science Park Innovation Way Heslington York YO10 5NY tel +44 (0) 1904 435349 fax +44 (0) 1904 435356 mobile +44 (0) 788 191 3004 http://www.ynic.york.ac.uk http://www.york.ac.uk/chym/ https://www.ynic.york.ac.uk/about-us/people/ggrg

8 years, 11 months

YNiC talks today

by Junior Whiteley

Dear users, Two talks will be given today at 4pm in B020. Mladen Sormaz will help us understand the contents of this thoughts on resting state brains in a talk entitled: ‘Understanding the content of thought’ Charlotte Murphy will then dazzle us with her eloquence and sagacity via a talk entitled: ‘Distinguishing stimulus independence from representation’ As always there will be refreshments in C Block reception after the talks. We look forward to seeing you there. All the best, Junior -- Junior Whiteley York Neuroimaging Centre junior.whiteley(a)ynic.york.ac.uk

8 years, 11 months

Looking after equipment in the TMS lab

by Bruce Keefe

Please can I remind all TMS operators and anyone using the TMS lab to take due care when using and putting away the TMS coils. Today we have found that four of the tracking spheres on the coil trackers needed replacing. The retroreflective surface on the spheres is delicate and will wear if touched or knocked. This will lead to inaccurate tracking for your experiments as the centre of the sphere will be misestimated by the Brainsight system. Further, this suggests that the coil trackers are getting knocked which is not ideal as these are delicate, precision instruments. It is important that you check the spheres on the coil trackers each time you run an experiment. If you find they are damaged please talk to Andre or myself. We can then help you replace the markers and order more as required to make sure experiments can continue to run smoothly I have attached a photo of one of the damaged spheres from today for reference Thanks Bruce [image: Inline images 1]

8 years, 11 months

Symposium Announcement: Computational Modelling of the Visual System

by Marc Himmelberg

Dear All, I am pleased to announce that Department of Psychology will be hosting the Computational Modelling of the Visual System symposium as a part of the NextGenVis Marie Skłodowska-Curie Innovative Training Network. The symposium is scheduled for Saturday, 17th September 2016 and will take place at Kings Manor, York. Keynote speakers for the symposium are Aviv Mezer (The Hebrew University, IL), Bob Dougherty (Stanford, USA) and Geoff Aguirre (University of Pennsylvania, USA). *Registration:* If you would like to register to attend there is a fee of £32 - this fee covers symposium registration, tea and coffee, and lunch. If you wish to pay with your M-Code budgets, please note that it will be attributed to the *next* financial year. If you would like to register, please send your name to marc.himmelberg(a)york.ac.uk. You will be required to send your work order or M-Code to finance at the start of August. Alternatively, cheques and cash are acceptable. *The registration deadline is 30th June.* Best, Marc and Barbara -- Marc Himmelberg PhD Student PS/C224, Department of Psychology University of York York, YO10 5DD UK

8 years, 11 months

easycaps for EEG

by Gary Green

Dear Users YNiC used to have a set of headcaps for use with EEG. These were of different sizes for children up to adults. The complete set has been removed from the box in the MEG area that is labelled for these caps. I am sure that they were borrowed for a perfectly good scientific reason but we would like them back. No questions will be asked Gary -- --------------- Gary Green York Neuroimaging Centre & Centre for Hyperpolarisation in Magnetic Resonance The Biocentre York Science Park Innovation Way Heslington York YO10 5NY tel +44 (0) 1904 435349 fax +44 (0) 1904 435356 mobile +44 (0) 788 191 3004 http://www.ynic.york.ac.uk http://www.york.ac.uk/chym/ https://www.ynic.york.ac.uk/about-us/people/ggrg

8 years, 11 months

Fwd: Fwd: RE Biocentre - Fire Alarm Test - Thursday 2nd June 2016

by Gary Green

Hi All, Apologies for the short notice; however, would you please be advised that the witnessing of the fire alarm system within the YNiC MRI Extension has been re-scheduled for Thursday 2nd June 2016 between the hours of 16.00pm & 18.30pm approximately. Due to the nature of the test being that the alarms will need to be activated; so to avoid anyone leaving the building, on each activation and it may need to be carried out on a number of occasions; the alarm will only sound for a short period of time (30 seconds approx). Although it is anticipated that a smooth operation of the above will be carried out successfully; should the alarm sound continuously for more than 1 minute, then all precautions need to be taken and all personnel should leave the building and go to their designated muster point. It is also assumed that these tests will at some point effect the Fire Alarm System in CHyM; although these will be alerts rather than full sounder activation; however, once again, should the alarms sound for more than 1 minute; the same will apply to the occupants of CHyM and all personnel should make their way out of the building as appropriate. In order to assist in making the end user / operatives aware, We will be affixing notices at the entrance doors of both the Biocentre and CHyM Buildings advising of this test on Thursday afternoon (2/6/16). Gary Green

8 years, 11 months

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ynic-users June 2016