Problems with Downsample to atlas

Discussions
1

Hello!

When I performed this step, and chosed "Desikan-Killiany"
image

I got this:
image

Then when I performed this step:

image
image737×578 153 KB

I got this:

image
image830×424 85.6 KB

"ImageGridAmp" matrix is a 68×1875 sized matrix, I know 68 represents 68 regions according to the "Desikan-Killiany" partition, and 1875 represents the sampling points. I would like to know what transformations have been made to the dipoles in these 68 regions and eventually, each region retains only one value? In other words, how do the amplitudes of so many dipoles in each area merge into one value?

Thank you for your time!

Sincerely
Ziwei Ruan

2

The function used is the scout function, which is the mean by default:
https://neuroimage.usc.edu/brainstorm/Tutorials/Scouts#Scout_function

We do not recommend using this process "Downsample to atlas", it creates files that are difficult to manipulate, and as you reported, not very intuitive. I'd recommend you use the process "Extract > Scouts time series" instead, it would give the same results, but as a "matrix" file (68 signals) instead of a "source" file (source maps displayed in 3D).