If your task only has condition A and condition B, then the SPM PPI approach will work; however, if you have fixation, condition A, and condition B, then you should use the gPPI toolbox. If you have more than 2 conditions in your experiment, you should also use the gPPI toolbox. It doesn't matter if you want to limit the analysis to the two conditions, the key is that you need to estimate the connectivity for all aspects of the experiment.gPPI is fully automated/scriptable and uses the existing first-level Task models.Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Postdoctoral Research Fellow, GRECC, Bedford VA
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
=====================
This e-mail contains CONFIDENTIAL INFORMATION which may contain PROTECTED
HEALTHCARE INFORMATION and may also be LEGALLY PRIVILEGED and which is
intended only for the use of the individual or entity named above. If the
reader of the e-mail is not the intended recipient or the employee or agent
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action in reliance on the contents of this information is strictly
prohibited and may be unlawful. If you have received this e-mail
unintentionally, please immediately notify the sender via telephone at (773)
406-2464 or email.On Thu, May 28, 2015 at 10:31 AM, Jingting Zhang <[log in to unmask]> wrote:Hi Donald,Thanks for your prompt reply! The classification accuracy maps from the whole-brain searchlight analysis were normalized and smoothed for the second-level analysis. I'd like to use the native space for the GLM model to create the PPI interaction term, just because my searchlight was done on native space at the first level, so best keep consistent. gPPI is powerful - it's just that I've got things set up in SPM PPI ready to go, so wonder whether it's doable in the original SPM PPI also? If not, perhaps will have to switch to gPPI:)Many thanks again.Best,Jingting--On Thu, May 28, 2015 at 8:25 AM, MCLAREN, Donald <[log in to unmask]> wrote:What was normalized and smoothed for the second-level?gPPI analysis (via the gPPI toolbox) can be done at either in native or normalized space. It depends on what you are trying to do.Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Postdoctoral Research Fellow, GRECC, Bedford VA
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
=====================
This e-mail contains CONFIDENTIAL INFORMATION which may contain PROTECTED
HEALTHCARE INFORMATION and may also be LEGALLY PRIVILEGED and which is
intended only for the use of the individual or entity named above. If the
reader of the e-mail is not the intended recipient or the employee or agent
responsible for delivering it to the intended recipient, you are hereby
notified that you are in possession of confidential and privileged
information. Any unauthorized use, disclosure, copying or the taking of any
action in reliance on the contents of this information is strictly
prohibited and may be unlawful. If you have received this e-mail
unintentionally, please immediately notify the sender via telephone at (773)
406-2464 or email.On Thu, May 28, 2015 at 9:09 AM, Jingting Zhang <[log in to unmask]> wrote:Dear List,My multivariate analysis (using support vector machine, svm) showed a neural network that classifies one condition more often than the other. Currently, I'd like to do a PPI analysis on this network. For the multivariate analysis, native-space unsmoothed data were used for 1st-level and then normalised and smoothed at 2nd-level.Would it be best if do a GLM of the unsmoothed native-space data at the 1st level to extract BOLD signal and then generate the PPI interaction term for each subject?Thanks very much!Best,JingtingJingting