AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

History of AFNI updates  

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March 24, 2009 10:08AM
Christine,

You can try Bob's approach, but if you want to stick with 3dRegAna, your regression model is

Y = b_0 + b_1 * X + b_2 X^2 + e

> We would like to be able to say that activity in brain area A fits a linear
> function, better than it fits a quadratic function.

You would be able to see in such a region b_1 is significantly different from 0 while b_2 is not.

> Conversely, we would like to be able to say that brain activity in area B fits a
> quadratic function, better than it fits a linear function.

In this case you should simply have b_2 significantly different from 0.

HTH,
Gang
Subject Author Posted

3dRegAna-comparing linear versus nonlinear vectors

Christine Smith March 23, 2009 06:29PM

Re: 3dRegAna-comparing linear versus nonlinear vectors

Bob Cox March 24, 2009 08:34AM

Re: 3dRegAna-comparing linear versus nonlinear vectors

Gang Chen March 24, 2009 10:08AM

Re: 3dRegAna-comparing linear versus nonlinear vectors

Christine Smith March 24, 2009 01:14PM

Re: 3dRegAna-comparing linear versus nonlinear vectors

Gang Chen March 24, 2009 01:40PM

Re: 3dRegAna-comparing linear versus nonlinear vectors

Christine Smith March 24, 2009 05:57PM

Re: 3dRegAna-comparing linear versus nonlinear vectors

Gang Chen March 24, 2009 06:22PM

Re: 3dRegAna-comparing linear versus nonlinear vectors

Pat Bedard March 24, 2009 08:02PM