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Can a single Gaussian function be selected for hmrR_GLM

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hello everyone,
Event related experimental design should use a single Gaussian function and stimulus convolution,
but currently the parameter idxBasis in hmrR_GLM seems to only allow for the selection of continuous Gaussian functions.
Can I achieve a single Gaussian function through parameters such as step size? Is this reasonable? Is there a better analytical method for designing event related experiments(such as handle GLM in NIRS-SPM)

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Meryem Yücel
Posts: 211
Joined: 4 years ago



While I disagree with "should", I think what you are looking for is a fixed model for HRF (canonical). The second and third option among GLM HRF model options in homer are gamma and modified gamma functions which fall under this. You can use them. Just make sure you have the right duration of stims in your event.tsv files as they will be used for the convolution.


Hope this helps,





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Joined: 3 weeks ago

Active Member
Posts: 6

Thank you for answered my question,mayucel. You are so nice. 🤗

Could you please continue to answer my questions?
1.Is the method of using continuous Gaussian functions to obtain HRF called deconvolution, and is it a more advanced GLM?
2.For event related experimental design, the duration set in SPM seems to be 0, but When I set the duration in event.tsv to 0, there was an error in GLM's calculation. How do I set the duration of an event?

Thank you again

Jia Songliln