Hi Sumit,

Oasis database only provides resting state fMRI images. So even if the sequence description can be misleading, they refer to rs-fMRI. Probably they wanted to indicate that the only task that subject has to do is to rest.

Moreover, many rs-fMRI sequences have also baseline and active measurement in paradigm size, even if there is no task to be performed.

Hi Vincenzo Alfano. Thank you for the clarification.

Hi Sumit Swargiary ,

Agree. If you check the about section. Different modalities (DTI, FLAIR,...) as well as rs-fMRI is listed there.

https://www.oasis-brains.org/#about

Also, I suppose that they wanted to make an organized directory or list of file names by selecting that label. It is possible that the same group was used in later investigation for task-based imaging.

They are probably using the BIDS data format for organizing and naming brain imaging data (https://bids.neuroimaging.io/). This has now become the standard. In this format for naming files, "rest" is the "task" that the participants are doing, i.e. resting-state is considered as the task being assigned to the participants during scanning, which is why you see "task_rest", which implies that the task is resting-state. It thus is resting-state fMRI data itself.