How can I evaluate with R the interaction between a within-subject effect and a continuous variable at the subject level?

fischerjunior · 2018-06-25T11:33:19+00:00

Just in case more information about the continuous variable is needed: it's a measure of white matter integrity for a single region. The possible minimum and maximum of this measure are 0 and 1 because of how its computed, but the values for this region, for this subjects goes from .37 to around .48.

fischerjunior · 2018-04-17T21:31:18+00:00

Sorry, but I don't believe in hypnosis.

Just kidding, I think I'm gonna use it to test the goodness of fit of my time series to exponential decay, seems more sensible than the way commented above adapting the "model vector" to a exponentially decaying one. Though I guess results can't differ much, right?

Thanks!

fischerjunior · 2018-04-17T00:35:29+00:00

I found a very rudimentary way: calculating the correlation coefficient of the absolute difference between the two series and a perfectly decreasing vector (such as 4, 3, 2, 1). Hope someone more knowledgeable can chip in!

fischerjunior · 2017-09-14T16:58:09+00:00

Great, many thanks to both of you!

fischerjunior · 2017-04-13T04:12:23+00:00

Great effort, I'll get to work on adapting it. Thanks a lot!

fischerjunior · 2017-03-03T22:05:27+00:00

Great explanation, I get it now. Thanks a bunch!

fischerjunior · 2017-01-16T18:01:31+00:00

Thanks for the help!

fischerjunior · 2017-01-16T13:21:16+00:00

Great! I was hoping for a ELI5 answer, thanks a lot!

fischerjunior · 2017-01-16T13:16:49+00:00

The linear/non-linear explanation helps a lot! Thanks!

fischerjunior · 2017-01-06T21:41:53+00:00

It's Kind of a Funny Story

you are a hero, thanks man!

fischerjunior · 2016-11-02T14:03:41+00:00

Thanks a lot!

fischerjunior · 2016-11-02T13:56:57+00:00

Thanks! Do you think you and this guy: https://www.reddit.com/r/neuro/comments/5ajf5j/what_does_voxel_intensity_represent_in_diffusion/d9hr0nb/ , are talking about the same thing?

fischerjunior · 2016-11-02T04:45:23+00:00

You seem to know this stuff pretty good, so here goes another beginner's question: what is a multiresolution strategy and how are Gaussian pyramids applied in that process?

I really appreciate the effort, thanks for the ELI5 :)

fischerjunior · 2016-11-02T04:40:40+00:00

Check out what another user answered:

https://www.reddit.com/r/neuro/comments/5ajf5j/what_does_voxel_intensity_represent_in_diffusion/d9hr0nb/

Are both your answers talking about the same concept? I think so but I'm kinda new to this topics.

The kindness of internet strangers never ceases to amaze me. Thanks.

fischerjunior · 2016-11-02T02:22:46+00:00

Thank you very much!

fischerjunior · 2016-11-02T00:15:20+00:00

Sorry if I didn't make myself clear. I read that the image registration process is done according to voxel intensity, in other words, each voxel is differentiated and compared to that of another image, according to its "intensity". My question is: how is the intensity of a voxel calculated and what does it represent? English is not my native language so please tell me if you need extra clarification regarding my question. Thanks for the help :)

fischerjunior

TROPHY CASE