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Dear Vladimir, Thanks for your response.I have another request.Would you please try the "coarse" mesh using 'Single shell' again? Comparing to the 'normal' mesh,the active brain regions are quite different. It is very stange and don't know why? Our concern is activation of brain regions map and I evalute the results by the activation map.I summarize the 3D reconstruction results ,eg time band 300-400ms, frequency band of interest 0 HZ.would you please spend some time on this issue again? Thanks very much! best , -- haiteng jiang Research Center for Learning Science, Southeast University Si Pai Lou 2 # , Nanjing, 210096, P.R.China Brain Imaging Lab Email: [log in to unmask] 在2009-07-28?00:39:16，"Vladimir?Litvak"?<[log in to unmask]>?写道： >Dear?Haiteng, > >I?looked?at?your?data?and?there?is?nothing?fundamentally?wrong?with >it.?As?a?rule?of?thumb?I'd?say?use?'Single?shell'?if?you?have >individual?anatomy?and?'Single?sphere'?otherwise.?In?your?case?both >options?lead?to?solutions?somewhere?in?the?ventral?visual?pathway >which?is?what?one?would?expect,?however?with?single?sphere?the?highest >activation?is?more?posterior.?I?only?tried?the?'normal'?mesh.?If?you >look?at?the?log-evidence?you?can?see?that?the?highest?evidence?is >actually?for?single-sphere.?This?means?that?this?is?probably?a?better >option?to?use?in?your?case.?I?don't?think?there?is?any?bug?here. > >Hope?this?helps. > >Vladimir > >2009/7/27?hiten?<[log in to unmask]>: >>?Dear?Vladimir, >>??Thanks?for?your?time,They?have?been?very?helpful.Since?the?file?is?too?big >>?,so?I?use?another?email([log in to unmask])to?send?you??my?data.I?am?very >>?sorry?for?the?resulting?inconvenience.?You?can?download?the?four?files >>?fowlling?the?two?steps?as?the?attachment?described. >>????The?warnings?don't?arise?when?I?choose??'single?Sphere'?or?'MEG?local >>?spere',and?the??results?of?3D?reconstruction??using???'MEG?local?spere'?seem >>?to?very?be?good.?I?am?surprised?that?the?results?of?'single?shell'?are?quite >>?different?between??"normal"?mesh?and?"coarse"?mesh?using?standard?imaging >>?approach.The?result?of?'coarse'??mesh??make?sense?while??"normal"?mesh?not. >>?I?summarize?the?results?of?inverse?reconstruction?as?an?image?,setting?time >>?band?and?specifying?a?frequency?band?of?interest?as?zero. >>??The?test?is?incongruent?color-words?Stroop?task?by?a?a?healthy?female,. >>?Every?picture?prensents?300?ms,ISI?3000ms,64?trials.?I?have?pre-processed >>?the?MEG?data??as?following,epoching?pre-stimulus?-200ms,post-stimulus?800 >>?ms;bandpass?filter?5-30hz.?Previous?neuroimaging?studies??in?healthy >>?volunteers?show?that?anterior?cingulated?cortex?appears?to?be?heavily >>?involved?int?the?task. >>???It?would?be?very?grateful?if?you?spend?some?time.Looking?forward?to?your >>?answer.Thanks?again! >>??best, >>??haiteng >> >>?在2009-07-27?16:35:07，"Vladimir?Litvak"?<[log in to unmask]>?写道： >>>Dear?Haiteng, >>> >>>Those?warnings?are?normal?and?are?not?the?reason?why?your?results?do >>>not?make?sense.?I?think?if?you?choose?'Single?sphere'?model?there?will >>>be?no?warnings?but?the?results?should?not?be?very?different.?Imaging >>>source?reconstruction?even?with?very?sophisticated?methods?used?in?SPM >>>is?not?guaranteed?to?give?you?the?right?answer.?You?can?try?to?improve >>>the?results?by?limiting?the?time?window?to?the?part?you?are?interested >>>in?and/or?filtering?your?data?in?a?narrower?band?around?the >>>frequencies?you?expect?to?contain?your?physiological?signals.?Try >>>playing?with?different?options?in?the?'Custom'?button.?If?you?don't >>>manage?to?make?any?progress,?send?us?an?example?of?your?data?and?some >>>details?about?the?paradigm?and?we'll?look?at?at?it.?How?long?is?your >>>ERP??Is?it?2?min??If?so?I?wouldn't?be?surprised?3D?may?fail. >>> >>>Best, >>> >>>Vladimir >>> >>> >>> >>>2009/7/27?hiten?<[log in to unmask]>: >>>>?Dear?SPMers: >>>>??After?pre-processing?,I?load?MEEG?dataset?which?is?averaged?to?do?3D?source >>>>?reconstruction?.I?use?the?subject's?sMRI,choose?'normal'?mesh,select?our >>>>?used?nasion?and?preauricular?points?as??fiducials,then?go?to?the?Forward >>>>?computation?using?single?shell?model?,following?warning?arises: >>>>?using?headmodel?specified?in?the?configuration >>>>?using?gradiometers?specified?in?the?configuration >>>>?computing?surface?normals >>>>?Warning:?Matrix?is?close?to?singular?or?badly?scaled. >>>>??????????Results?may?be?inaccurate.?RCOND?=?4.227452e-017. >>>>>?In?fieldtrip\private\meg_ini>getcoeffs?at?94 >>>>???In?fieldtrip\private\meg_ini?at?36 >>>>???In?fieldtrip\private\prepare_vol_sens?at?270 >>>>???In?fieldtrip\private\prepare_headmodel?at?223 >>>>???In?fieldtrip\private\headmodelplot?at?205 >>>>???In?ft_headmodelplot?at?11 >>>>???In?spm_eeg_inv_checkforward?at?70 >>>>???In?spm_eeg_inv_forward_ui?at?48 >>>>???In?spm_eeg_inv_imag_api>Forward_Callback?at?87 >>>>???In?spm_eeg_inv_imag_api?at?53 >>>>?undoing?the?G3BR?balancing >>>>?undoing?the?G3BR?balancing >>>>?Foward?model?complete?-?thank?you >>>>?Ignoring?that?,next?I?choose??"Standard"?inversion,produciing?below >>>>?warnings: >>>>?computing?surface?normals >>>>?Warning:?Matrix?is?close?to?singular?or?badly?scaled. >>>>??????????Results?may?be?inaccurate.?RCOND?=?4.206769e-017. >>>>>?In?forwinv\private\meg_ini>getcoeffs?at?94 >>>>???In?forwinv\private\meg_ini?at?36 >>>>???In?forwinv\private\prepare_vol_sens?at?270 >>>>???In?forwinv_prepare_vol_sens?at?11 >>>>???In?spm_eeg_lgainmat?at?91 >>>>???In?spm_eeg_invert?at?115 >>>>???In?spm_eeg_invert_ui?at?95 >>>>???In?spm_eeg_inv_imag_api>Inverse_Callback?at?94 >>>>???In?spm_eeg_inv_imag_api?at?53 >>>>?NB?:According?to?my?test?paradigm,?the?inverse?result?can?not?make?sense??at >>>>?all. >>>>?Any?suggestion??Thanks?in?advance! >>>> >>>> >>>>?-- >>>>?haiteng??jiang >>>>?Research?Center?for?Learning?Science, >>>>?Southeast?University >>>>?Si?Pai?Lou?2?#?,?Nanjing,?210096,?P.R.China >>>>?Brain?Imaging??Lab >>>>?Email:?jianghaiteng@126com >>>> >>>> >>>>?________________________________ >>>>?网易YEAH.NET免费邮箱：您的终身免费邮箱 >> >> >>?________________________________ >>?网易YEAH.NET免费邮箱：您的终身免费邮箱