BIDS format onset files



I am pretty new to neuroimaging and I’ve been teaching myself FSL. I want to use some of the datasets from Openfmri for practice but I don’t understand this new BIDS onset file structure. The onset files I got have trial_type as the third column instead of parametric modulation and FSL won’t accept it that way as a 3-column format when modelling the task. So do I separate those onset files myself and create new onset text files for each condition or do we have a method to use them in FSL that I don’t know about ?


To understand the _events.tsv please read section 8.5 of the BIDS specification (

In context of FSL you might be interested in this tool:


Thanks Chris. These are pretty useful.