Back to PLS HelpMultiblock PLS
Posted on 01/11/13 11:07:32
Number of posts: 9
I have a question about when to use Multiblock PLS vs Behaviour PLS. If you wanted to explore the connectivity of a seed and how this connectivity is reflected by task, would it be better to use Multiblock rather than Behaviour PLS?
Thanks so much,
Signy
Thanks so much,
Signy
Replies:
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I'm Online
Posted on 01/11/13 11:10:35
Number of posts: 291
If you wanted to explore the connectivity of a seed and how this connectivity is reflected by task, you should use Seed PLS:
http://www.rotman-baycrest.on.ca/pls/userguide.htm#_Toc303956393
http://www.rotman-baycrest.on.ca/pls/userguide.htm#_Toc303956393
Untitled Post
Posted on 01/11/13 11:21:01
Number of posts: 9
Thanks for your quick reply! In a previous post is was noted that "Multiblock is a combination of task PLS and behaviour PLS and is meant to identify spatiotemporal patterns that simultaneously reflect activity differences and relate to some aspect of behaviour". I guess I am just a little confused as to what situations multiblock is better to be used than bPLS (either with a seed to look at connectivity or with behaviour)?
Untitled Post
I'm Online
Posted on 01/11/13 11:26:51
Number of posts: 291
Multiblock is a combination of task PLS and behaviour PLS. However, if you want to explore the connectivity of a seed and how this connectivity is reflected by task, it is better to use Seed PLS: Of cause, you can try multiblock, but I don't know whether it is better or not.
Untitled Post
Posted on 01/11/13 11:51:47
Number of posts: 394
quote:
Thanks for your quick reply! In a previous post is was noted that "Multiblock is a combination of task PLS and behaviour PLS and is meant to identify spatiotemporal patterns that simultaneously reflect activity differences and relate to some aspect of behaviour". I guess I am just a little confused as to what situations multiblock is better to be used than bPLS (either with a seed to look at connectivity or with behaviour)?
hi signy
to be clear, multiblock is *only* when you want to combine a task PLS with behavior/seed PLS. Running the seed PLS will tell you whether a pattern of functional connectivity differs by task/group, so if your question is just that, stick with seed PLS (as run with the 'behavior' module).
I hope that's clear
cheers
Randy
Thanks for your quick reply! In a previous post is was noted that "Multiblock is a combination of task PLS and behaviour PLS and is meant to identify spatiotemporal patterns that simultaneously reflect activity differences and relate to some aspect of behaviour". I guess I am just a little confused as to what situations multiblock is better to be used than bPLS (either with a seed to look at connectivity or with behaviour)?
Untitled Post
Posted on 01/11/13 14:21:13
Number of posts: 9
Thank you for your response. I may still be a bit confused as to when multiblock is a good idea. Just to clarify, if I wanted to how a seed voxel (e.g., a voxel in the the hippocampus) was connected functionally to the rest and the brain and if this dfifered between experimental conditions, I would used bPLS. If I wanted to know if activity in this seed voxel recruited distinctive networks for conditions (e.g. task demands), I would used multiblock?
Best,
Signy
Best,
Signy
Untitled Post
Posted on 01/11/13 14:57:20
Number of posts: 394
quote:
Thank you for your response. I may still be a bit confused as to when multiblock is a good idea. Just to clarify, if I wanted to how a seed voxel (e.g., a voxel in the the hippocampus) was connected functionally to the rest and the brain and if this dfifered between experimental conditions, I would used bPLS. If I wanted to know if activity in this seed voxel recruited distinctive networks for conditions (e.g. task demands), I would used multiblock?
Best,
Signy
Not exactly, but close :)
perhaps think about it in terms of input to PLS.
For task PLS, you are always looking at changes in mean activity between tasks/groups (activations), so you input mean activity
for behav/seed PLS, you are looking and changes (or similarities) in correlations between tasks/groups (functional connectivity in the case of seed PLS), so you input correlations
the multiblock allows you to identify spatial maps that represent the intersection of activations and functional connectivity, where you input means and correlations
To answer you questions as to whether the hippocampus recruited distinct networks for conditions, you would always use bPLS (its actually the same as asking whether functional connectivity w the hippocampus differs across conditons). That question requires analysis of correlations.
is that getting closer?
Randy
Thank you for your response. I may still be a bit confused as to when multiblock is a good idea. Just to clarify, if I wanted to how a seed voxel (e.g., a voxel in the the hippocampus) was connected functionally to the rest and the brain and if this dfifered between experimental conditions, I would used bPLS. If I wanted to know if activity in this seed voxel recruited distinctive networks for conditions (e.g. task demands), I would used multiblock?
Best,
Signy
Untitled Post
Posted on 01/18/13 12:15:56
Number of posts: 9
Thank you for your reply. I *think* I got it now! One last question, what types of questions are best answered with multiblock?
Thanks again,
Signy
Thanks again,
Signy
Untitled Post
Posted on 01/18/13 12:38:30
Number of posts: 394
quote:
Thank you for your reply. I *think* I got it now! One last question, what types of questions are best answered with multiblock?
Thanks again,
Signy
Anytime you want to link activation analysis to brain/behavior or functional connectivity. For example, if you see an activation pattern, say task vs basline, you may also want to know how that pattern of activity differences relates to task performance. You would thus include something like accuracy in the multiblock and identify the pattern of activations that predicts good/bad performance and those patterns that do not.
Thank you for your reply. I *think* I got it now! One last question, what types of questions are best answered with multiblock?
Thanks again,
Signy
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