Dear SPM experts
We have problem in model estimation step for one of our fmri experiment. Any
help is highly appreciated.
Jian
Our design:
4 stimulus types (drawings, words, faces, crosshair/baseline).
Seven cycle of the following:
10x drawings, one every 3s
10x words, one every 3s
10x faces, one every 3s
10x crosshair, one every 3s
Each cycle has different stimuli but the same order of stimulus type. All up
there are 70 of each stimulus type.
Model was set up as following:
Timing parameters:
Units for design: seconds
Interscan interval: 3
Microtime resolution and onsets default
Data & Design:
4 conditions set up as per each stimulus type – definitely set up correctly
Multiple conditions - none
High-pass filter – default
Factorial design - no
Basis Functions
Canonical HRF
Model derivatives: Time and Dispersion derivatives
Model Interactions – no
Global normalisation – none
Explicit mask – no
Serial correlations – AR(1)
Press 'Estimate' – runs almost to the end when this error message (below)
appears
--
Temporal non-sphericity (over voxels) : ...REML estimation
ReML Block - 1
ReML Iteration : 1 ...NaN
Warning: Matrix is close to singular or badly scaled.
Results may be inaccurate. RCOND = -1.000000e+00.
>In spm_reml at 89
In spm_spm at 855
In spm_config_fmri_est>run_est at 390
In spm_jobman>run_struct1 at 1474
In spm_jobman>run_struct1 at 1482
In spm_jobman>run_struct1 at 1482
In spm_jobman>run_struct at 1436
Error running job:
Error using ==> svd
NaN or Inf prevents convergence.
--------------------------
Done.
[Press 'Results': This error message comes up]
SPM5: spm_results_ui (v$Rev: 656 $) 12:00:36 - 30/04/2007
========================================================================
??? Reference to non-existent field 'xVol'.
Error in ==> spm_getSPM at 197
q = SPM.xVol.M - speye(4,4);
Error in ==> spm_results_ui at 264
[SPM,xSPM] = spm_getSPM;
??? Error while evaluating uicontrol Callback.
--
It will run without error if either one of
Basis Functions
Canonical HRF
Model derivatives: T&D derivatives
or
Serial correlations – AR(1)
But not if both
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