Hey. I am designing a few tasks that I would be running with simultaneous fNIRS-EEG combined data collection.
The tasks I am using are letter search task, connors continuous performance task, stop signal task and working memory change detection task.
I need some help desiging the tasks. How should the task be designed - number of trials, delay between trials and other aspects?
I generally suggest that tasks that work with fNIRS/fMRI usually work with EEG/ERP/MEG. There has been excellent success in using both fast and slow event-related design with combined imaging as well as mixed (blocks of event-related) designs.
You can use a variety of software packages to simulate/design the paradigm such as optseq (Optseq Home Page) or AFNI (Chapter 5: Creating Timing Files — Andy's Brain Book 1.0 documentation).
Generally for EEG/ERP/MEG you’re looking to maximize signal to noise ratios which are roughly 1/sqrt(N_TRIALS). Reasonable folks over the years have debated how many trials are necessary with ranges of 25 (hopefully usable) trials per condition all the way up to hundreds of trials per condition. This nuance is that we see titration of the neural signal after some number of trials less than 20, so what impact you get on the first trial may be quite different from those on later trials when your participant is likely thinking of how to spend the money you’re paying them for doing the task.
For your Continuous Performance Task - you likely want to look into using some form of connectivity or inter-subject correlation. Monica Rosenberg at Chicago has done a lot of things with this; as has David Jangraw at Vermont.
But if you have discrete events, aim for 25-50 trials per condition, add spacing (aka jitter) between your trials of 2-16 seconds, and randomize the presentation of trials and read some of the following resources with helpful chapters on these topics.
Gentle intro to mixed design: The mixed block/event-related design - PMC
EEG-fMRI book: Amazon.com: Simultaneous EEG and fMRI: Recording, Analysis, and Application eBook : Ullsperger, Markus, Debener, Stefan: Kindle Store
fMRI book: Functional Magnetic Resonance Imaging: 9780878936274: Medicine & Health Science Books @ Amazon.com
Another fMRI book: fMRI (The MIT Press Essential Knowledge series): Bandettini, Peter A.: 9780262538039: Amazon.com: Books
Talk on paradigm design (fMRI focused): https://youtu.be/rqTHMzNQpEU
High-level talk I gave on multimodal imaging: https://youtu.be/NustSfl6Flk
Medium-level talk on EEG-fMRI: https://youtu.be/7maQR5aDHQg
Talk on ISC/Naturalistic stimuli that goes into stimulus design a bit: https://youtu.be/Sc0TvVl2wXo
A link to all talks and slides from the NIH fMRI Summer Course: https://fmrif.nimh.nih.gov/index.php/SummerCourse
Thank you!
I will look into this. If I need any help, may I contact you?
Could you please share you linkedin if that’s okay?
Regards,
Stuti Mehta