Plotting the BOLD response (Y) against a PM modulator isn't really feasible. You have 24 values of the PM and many more time points per block as well as time points not associated with the task. The con_ value represents the slope of the PM.

If you want a plot of the PM regressor versus the BOLD signal across all time points irrespective of whether the task is present or not, you could could residualize the voxel values for all columns in the design matrix, except for the PM regressor. You could then residualize the PM regressor for all columns in the design matrix except for the PM regressor. Then plot the residualized values. This would produce what the GLM analyzed.

The easiest way to do this would be to load the data and the design matrix into a standard statistical package and residualize the values. If you are good in matlab, you could script it matlab as well.

Hope this helps.

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
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On Tue, Apr 28, 2015 at 12:58 AM, avantika mathur <[log in to unmask]> wrote:

Hi!

I have created a spm.mat file for one subject (first level analysis).  It contains 6 sessions, with each session having 4 blocks of 30 sec each (i.e. alternating happy and sad music listening condition) and the corresponding parametric modulator (i.e positivity rating on a scale of 1-4). 

Using the contrast 0 1 0 0 0 0 0 0, repeated over the sessions.

 I get activity in Frontal Cortex. I would like to plot a graph showing activity magnitude on y-axis and Rating on the x-axis (i.e 1-4) at the peak voxel of activation ( -12 12 48). Can anyone assist me with the same.

Thanks in advance.

--

Avantika Mathur
Int.Phd student
National Brain Research Centre
Manesar,Gurgaon