You're getting very low VRFs because of the sub-TR estimation (TR=1.5, but TER=0.5), so you reduce your power to about 1/3. This is not a problem unless you analyze your data using an FIR. If you assume a shape, then the power will come back. doug
On 05/15/2012 11:41 AM, Andrew Valdespino wrote: > (1) Version: optseq2.c,v 2.21.2.1 > > (2) Computer operating system: Mac OS X Version 10.7.3 > > (3) Command line: optseq2 --ntp 230 --tr 1.5 --psdwin 0 24 0.5 --ev go > 7 36 --ev nogo 7 12 --nkeep 4 --o gonogo --nsearch 1000 > > (4) Description of the problem: This is in reference to a go/no-go > paradigm. I am getting very low Eff and VRFAvg values. Is this an > issue/ is common with go/no-go paradigms? If this is an issue, any > recommendations for appropriate modifications. A trial in my > experiment involves a countdown (duration 2 seconds) followed by the > event of interest (0.5 seconds) followed by a blank screen (3.5 > seconds). I set dPSD at 0.5 because this number is divisible by both > the --tr and trial length (7 seconds). > > (5) Log and/or summary files: > > Searched 1000 iterations for 0.002500 hours > Rate: 111.111 iterations per second > INFO: 211/1000 schedules were ill-conditioned > Number of iterations since last substitution 310 > Cost Avg/Std: 0.0105840 0.0060667 > Max Eff Encountered: 0.0154867 > Max VRFAvg Encountered: 1.6717 > Eff of Nominal Ideal XtX: 0.177183 > > Rank Cost ZCost NthIter Eff CB1Err VRFAvg VRFStd VRFMin > VRFMax VRFRng IXtXErr > 1 0.0155 0.808 597 0.015 0.157407 1.67 0.61 0.80 > 4.13 3.33 4723.04 > 2 0.0150 0.732 218 0.015 0.009259 1.58 0.50 0.87 > 3.03 2.15 4749.02 > 3 0.0149 0.708 82 0.015 0.009259 1.54 0.46 0.91 > 3.15 2.24 4882.85 > 4 0.0148 0.703 539 0.015 0.175926 1.56 0.52 0.94 > 3.86 2.91 4752.15 > ____________ > > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer -- Douglas N. Greve, Ph.D. MGH-NMR Center gr...@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422 Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting FileDrop: www.nmr.mgh.harvard.edu/facility/filedrop/index.html _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.
