Hi
red-yellow shows increasing positive regression coefficient with the
associated time course while dark blue-light blue shows increasing
negative regression coefficient wrt the time course.
If your time course is the inverse of your canonical design then blue
values who still show negative regression against the time course)
will in fact have positively regression coefficient wrt the original
design. That is, you can freely 'flip' the time course but then also
need to 'flip' the spatial map to make sure that once you multiply
these two together you get the same result (basically 1*1 = -1 * -1)
In TICA the associated time course basically is the avergae temporal
response across all the voxels (weighted y the vaue in the spatial
map) and also averaged across the population according to the subject/
session mode vector. Yes, you can trial average this time course and
get a representation of the overall avergae (across space and
population) average HRF shape.
best
christian
On 13 Feb 2008, at 19:57, Vishwadeep Ahluwalia wrote:
> Hi,
> I need help interpreting the IC maps. I'm confused about the color
> coding
> scheme.
> assuming my stimulus paradigm is such: 0001100011000
> Instance 1: i get a component with time series 0001100011000. How do i
> interpret the red and blue voxels?
> Instance 2: i get a component with time series 1110011100111. How do i
> interpret the red and blue voxels?
>
> As a separate question;
> Using TICA on 10 datasets, i got the task related component. Is it
> true that
> the time series for this component represents the time course of every
> activated voxel in the respective spatial map? if so, can i trial
> average
> this time course and validly estimate the shape of the BOLD response
> in
> those voxels?
> These ten datasets belong to one paradigm. Can i do a similar
> analysis on
> data from another paradigm(with different stimulus timings) and
> compare the
> effect sizes between the two paradigms? or would i have to run one
> single
> analysis for both?
>
> Thanks!
>
> -Vish
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