Integration of covariates in 1st level model

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1

Hi, in my project participants execute handgrip contractions during thermal stimulations. I would like to know if there is a way to introduce the temperatures as covariates in the 1st level model. I need to remove the non specific effect of thermal stimulations from the brain activity related to handgrip contractions.

thanks a lot

2

Hi @Ilariam9, and welcome to neurostars!

Do you have a continuous temperature reading that you can sample at every TR (or perhaps more accurately, average within each TR)?

Best,
Steven

3

Hi Steven,
Thanks for the answer.
For each trial I apply a temperature which is constant during the whole trial (so also during the handgrip contraction). In total, I apply two temperature, one corresponding to warm perception the other corresponding to pain perception, according to an individual thermal calibration. These two temperatures are randomized during the experiment, but for each trial the temperature is constant.

Thanks.
Ilaria

4

Hi @Ilariam9,

You can add two columns to your design matrix, one corresponding to temperature 1, and the other corresponding to temperature 2, where each column has 1s whenever that temperature is applied, and 0s otherwise.

Best,
Steven

5

Thanks a lot.
But after how I integrate it in the nilearn function?

Bests,
Ilaria

6

Hi @Ilariam9,

You might find these tutorials helpful: Examples - Nilearn

Best,
Steven

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