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Fixation-contingent presentation of stimuli in MEG
by a.ellis＠psych.york.ac.uk 19 Oct '07

19 Oct '07

FIXATION-CONTINGENT PRESENTATION OF STIMULI IN MEG Laura Barca and I ran an MEG experiment in which participants were instructed to fixate on a central point on a screen positioned 1 metre in front of them. A stimulus (e.g. a word) was then presented very briefly to the left or right of the fixation point. The aim was to track the processing through the brain of words presented in the right visual field, projecting directly to the left (language) hemisphere, or in the left visual field, projecting first to the left (non-language) hemisphere and presumably needing to be transferred across to the left hemisphere via the corpus callosum for processing. In the absence of eye movement monitoring we had to trust our participants to fixate centrally, and to rely on the brief presentations to assert that they could not have re-fixated in the time that the stimulus was on the screen. We can also point to differences in the patterns of brain activation we observed as indicating that we were successful on most trials of the experiment in controlling presentation as we wanted to. There are, however, people out there who could end up reviewing grant applications for further work who get very animated about the need for accurate fixation control in this kind of experiment. There are also two strands of future research that may need more accurate monitoring. One is work I would like to do following up Lisa Henderson's MSc project comparing the responses of dyslexic and non-dyslexic students to words presented in the left and right visual fields. The other is a project by a PhD student of Richard Wise at Imperial College London , Zoe Woodhead (a former undergraduate of ours), who want to use the York MEG system to look at word recognition in patients with hemianopias following occipital strokes. Both dyslexic and hemianopic participants may be assumed to have greater difficulty controlling their fixation than 'normal' participants, and good fixation control would be especially helpful for those studies. It would also help with studies I would like to do in which words will be presented centrally on the assumption that certain letters fall to the left of fixation while other letters fall to the right. What would be nice to have, then, is a way of ensuring that stimuli are only displayed on the screen when a participant is fixating on, or close to, a central fixation point. We normally offset the inner edge of our stimuli by 1.5 degrees, so it would be good to define a central fixation sphere with a radius of 0.5 degrees at 1 m distant from the participant, and only to present the stimulus on a given trial when fixation is within that sphere. So: 1. Would the resolution of the system allow us to know when someone is fixating within a sphere that has a diameter of 1 degree at 1 metre distance? Is a smaller resolution possible? 2. What would be the minimum time between registering that fixation is within the defined region and a stimulus appearing on the screen? I want to avoid suggestions that participants may have moved their eyes in the interval between fixation being registered and the stimulus being presented. It might help to present the stimulus after fixation has been within the central sphere for a certain period of time in order to exclude the possibility that participants were sweeping their eyes through the sphere when presentation was triggered. 3. Richard Wise and Zoe Woodhead would be interested in a variant of this procedure where a stimulus remains on the screen for as long as fixation remains within the central region. This would allow more prolonger presentation of stimuli to, for example, patients with hemianopias whose processing of visual inputs may be relatively slow. I know that Richard and Zoe have toyed with presenting "sentences" in one or other visual field by displaying one word after another at the same position. That would be OK to do if we could know that fixation remained central throughout. 4. Finally, I gather from the meeting last night that only one eye is monitored. There is quite a lot of discussion in the literature about how often the two eyes focus on the same point, and how often there is either 'crossed' or 'uncrossed' fixation. We would need to think about this, and whether we should, for example, put a patch over the unmonitored eye. I am posting this on ynic-users because we were encouraged to do so. I am hoping for a sober response from YNiC which is realistic about what could and could not be done, any difficulties we may run into, and the time that would be required to implement a system like this (assuming that it is do-able). At the moment all I need to know is what could or could not be achieved so that I can write that in confidence into grant applications. Other people with an interest in vision and MEG (Silvia, Piers, Andy Y etc) may want to chip in so that YNiC can get a fuller understanding of what people would like to have in the way of intergrated fixation monitoring and stimulus presentation. Andy Ellis 19 Oct 2007

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YNiC Seminar this week
by Gary Green 17 Oct '07

17 Oct '07

October 18th 4pm YNiC Open Plan 1. This autumn in YNiC - the programme 2. What is new and what has changed 3. Booking and the database 4. Ethics and governance 5. new tools 6. The support system explained 7. What is happening in YNiC - a look at the future 8. A discussion about users' needs and a new forum for getting users involved All welcome. Refreshments will be available. -- Gary Green York Neuroimaging Centre The Biocentre York Science Park Innovation Way Heslington York YO10 5DG http://www.ynic.york.ac.uk tel. 01904 435349 fax 01904 435356 mobile 07986 778954

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MEG and MRI
by Gary Green 17 Oct '07

17 Oct '07

You will probably be pleased to hear that MEG is now fully operational again. We have also taken time to get the system recalibrated, eye trackers installed and a complete overhaul of the mechanics of the bed. The noise level is lower as the source of the small electrical pulse artefacts has been identified and removed. All MEG channels are working. The original problem was due to a faulty interface between the fibre optics taking data out of the shielded room into the data acquisition rack. The board has been replaced. Bookings can now be taken for MEG. You may also be pleased to hear that MRI has had a routine maintenance and all is well. happy scanning! -- Gary Green York Neuroimaging Centre The Biocentre York Science Park Innovation Way Heslington York YO10 5DG http://www.ynic.york.ac.uk tel. 01904 435349 fax 01904 435356 mobile 07986 778954

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Fwd: Visual Dysfunction and Cognition in Childhood
by Andy Ellis 08 Oct '07

08 Oct '07

> > >Please bring this conference to the attention of colleagues who may >be interested- > >BPS Division of Neuropsychology > > >Visual Dysfunction and Cognition in Childhood > >This day conference will increase knowledge on psychological, >neurological and neurobiological systems involved in vision and >visual defects of brain and peripheral optic pathways. it will also >increase knowledge on brain:cognition relationships and cognitive >patterns associated with visual defects, including spatial >cognition, and severe visual impairment. The conference introduces >the latest theory and practice in these areas, including clinical >assessment and interpretation of cognitive development and disorders >in children with severe visual impairment. > >Date: 30 October 2007 > > >Who should attend? > >This event is open to clinical or educational practitioners or >researchers in child neuropsychology, clinical child psychology, >paediatric, neurology, occupational therapists and related >neuroscience disciplines. Relevant to practitioners and researchers. > > >Programme > >09:30 Registration & Refreshments > >10:00 Two visual systems: agnosia, optic ataxia & neglect > >Professor David Milner (Professor of Cognitive Neuroscience, >University of Durham): Co-author of Sight Unseen (winner of the BPS >Book Award) > >11:15 Refreshments > >11:30 Neurobiological models of visual-spatial deficits in childhood > >Professor Janette Atkinson (Director of Visual Development Unit: >University College London/ Oxford University): Author of The >Developing Visual Brain > >12:45 Lunch > >14:00 Visual impairment and cognition: neurodevelopmental issues > >Dr Naomi Dale (Head of Psychology (Neurodisability), Great Ormond >Street Hospital/ UCL Institute of Child Health): Co-lead in >developing the governmental Early Support Developmental Journal for >parents and children with VI > >14:45 Refreshments > >15:00 Visual impairment and cognition: clinical assessment and >interpretation > >Dr Naomi Dale (Head of Psychology (Neurodisability), Great Ormond >Street Hospital/ UCL Institute of Child Health): Co-lead in >developing the governmental Early Support Developmental Journal for >parents and children with VI > >15:45 Concluding Remarks > > >Speakers > >Professor David Milner (University of Durham): Co-author of Sight >Unseen (winner of the BPS Book Award) > >Professor Janette Atkinson (University College London/ Oxford >University): Author of The Developing Visual Brain > >Dr Naomi Dale (Great Ormond Street Hospital/ UCL Institute of Child >Health): Co-lead in developing the governmental Early Support >Developmental Journal for parents and children with VI. >Location Directions >UCL Institute of Child Health, London > >For further details click here- >http://www.ich.ucl.ac.uk/education/short_courses/courses/2S18 > >--------------------------------------------- >COGNEURO archives and subscription manager can be found at >http://www.jiscmail.ac.uk/lists/COGNEURO.HTML >--------------------------------------------- >List owner's email address: COGNEURO-request(a)jiscmail.ac.uk -- Professor Andy Ellis Department of Psychology University of York York YO10 5DD England Tel. +44 (0)1904 433140 http://www.york.ac.uk/depts/psych/www/people/biogs/awe1.html

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Draft programme for Thursdays at YNiC
by Gary Green 21 Sep '07

21 Sep '07

Attached is the 'draft' programme for YNiC Thursday evening seminars for the autumn and early winter. The current plan is that after Christmas the seminars would mainly consist of invited speakers, internal speakers and journal club. The third term would be devoted to people giving talks about work that has been or is about to be published from YNiC projects. ALL comments are welcome. Your ideas are absolutely essential to running a Centre that will make imaging research possible and fun for all. Please send your comments to me, Sam Johnson (science.manager(a)ynic.york.ac.uk) or Tony Morland (a.morland(a)psych.york.ac.uk) Gary -- Gary Green York Neuroimaging Centre The Biocentre York Science Park Innovation Way Heslington York YO10 5DG http://www.ynic.york.ac.uk tel. 01904 435349 fax 01904 435356 mobile 07986 778954

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[Re : Project presentations : Today
by Gary Green 20 Sep '07

20 Sep '07

Today we have two new project presentations (Thursday the 20th at 4pm in YNiC Open Plan) Project presentations will be made by Professor P. O'Higgins. HYMS. Scalp and head reconstruction from MRI. Dr. T. Jellema, University of Hull, Department of Psychology. Imaging in Autism. We will also announce what is being discussed for YNiC for the autumn term. Do come along and discuss training requirements, seminars and any other issues you would like to see scheduled for a Thursday afternoon. All welcome. refreshments will be available. -- Gary Green York Neuroimaging Centre The Biocentre York Science Park Innovation Way Heslington York YO10 5DG http://www.ynic.york.ac.uk tel. 01904 435349 fax 01904 435356 mobile 07986 778954

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Thursday Evening Sessions this autumn
by Gary Green 18 Sep '07

18 Sep '07

We are currently planning the Thursday evening sessions and other training sessions for next term. If you have any thoughts or ideas we would be keen to hear your views. The main sessions will start on the 18th of October. This week though we have two new project presentations (Thursday the 20th at 4pm in YNiC Open Plan) Project presentations will be made by Professor P. O'Higgins. HYMS. Scalp and head reconstruction from MRI. Dr. T. Jellema, University of Hull, Department of Psychology. Imaging in Autism. We will also announce what is being discussed for YNiC for the autumn term. Do come along and discuss training requirements, seminars and any other issues you would like to see scheduled for a Thursday afternoon. We will circulate the draft timetable and ask for comments by email as well. All welcome. refreshments will be available. -- Gary Green York Neuroimaging Centre The Biocentre York Science Park Innovation Way Heslington York YO10 5DG http://www.ynic.york.ac.uk tel. 01904 435349 fax 01904 435356 mobile 07986 778954

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Update on MEG
by Gary Green 17 Sep '07

17 Sep '07

I am sorry to say that MEG is still unavailable. 4D are working on the problem and believe that they have determined the cause. We expect an engineer to visit this week and ti make adjustments to the main power supplies to the system. As soon as MEG is available I will let you know. MRI is working fine Gary -- Gary Green York Neuroimaging Centre The Biocentre York Science Park Innovation Way Heslington York YO10 5DG http://www.ynic.york.ac.uk tel. 01904 435349 fax 01904 435356 mobile 07986 778954

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MEG unavailable
by Gary Green 13 Sep '07

13 Sep '07

I am sorry to have to report that MEG is currently unavailable. An electronics board that is the interface between the scanner and the main computer rack has failed. 4D have been informed and are trying to get a board to us as fast as possible. Unfortunately this may take more than a week as the new board will need substantial testing before it can be installed. I will keep you informed as to when MEG will be available again. I know this will cause some inconvenience and I apologise for the problems that this will undoubtedly bring to some projects. -- Gary Green York Neuroimaging Centre The Biocentre York Science Park Innovation Way Heslington York YO10 5DG http://www.ynic.york.ac.uk tel. 01904 435349 fax 01904 435356 mobile 07986 778954

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Stimulus Delivery at YNiC - Presentation licenses
by Andre Gouws 28 Aug '07

28 Aug '07

The Presentation licenses at YNiC have now been renewed for another year. If any users experience problems with the stimulus delivery PCs (especially if there are prompts for license files) please contact the DSO and / or email it-support(a)ynic.york.ac.uk Thanks -- ************************************************************************ Andre Gouws User Support Manager York Neuroimaging Centre The Biocentre York Science Park Heslington YO10 5DG Tel: +44 (0) 1904 435328 Fax: +44 (0) 1904 435356

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