This afternoon David Crewther will give a project proposal talk at 4 pm in YNiC open plan entitled "Nonlinearities in Multi-focal Magnetoencephalography" Abstract Multi-focal visual evoked potentials have become a standard tool in the diagnosis of glaucoma and retinal vascular disease. However, the randomization techniques employed to de-correlate sequences for stimulation of patches of visual field also offer the opportunity for analysis of non-linearities in evoked responses. These have been used to derive separate magnocellular and parvocellular contributions to the cortical VEP. Here we propose to develop similar m-sequence based pseudo-random stimulation techniques to MEG with the purpose of localizing the time-course of activation of the M and P pathways as they extend into dorsal and ventral cortical streams. A beam-former approach to this question will be followed, answering questions regarding the role of the “magnocellular advantage” in object recognition. An initial 13 patch cortically scaled m-sequence multi-focal stimulus has been developed. Extensions to higher resolution cortical imaging are proposed. However multi-focal fMRI imaging indicates eye-movement control is vital. Hence a gaze-contingent system using retinally-stabilized presentation is being developed that will allow an estimate of the optimal high resolution MEG mapping of visual cortex. All welcome *YNIC 5th Birthday drinks will be held immediately after the seminar* -- ************************************************************************ Dr. Rebecca E. Millman Science Liaison Officer York Neuroimaging Centre The Biocentre York Science Park Heslington YO10 5DG Tel: +44 (0) 1904 567614 Fax: +44 (0) 1904 435356