optseq won't be quite what you need because it is going to randomize the order (so you can't always get a feedback after each response). You can tell it that there is only one condition, then go back and recode. You'll probably want to control the min and max fixation, which you can do with optseq.
doug daniel geisler wrote: > Dear Freesurfers, > > We intend to implement a probabilistic reversal learning task (Hampton > et al, 2006) in an ER-design. Each of its 120 trials matches the > following pattern: > > |<---- Response ---->|<-- Fixation -->|<-- Feedback -->| > > The phases of Response and Feedback take 2 sec and 1 sec, > respectively. We are wondering how to setup the durations of Fixation > and the ITI in an optimal way, which means trading task-duration off > against efficiency. We would like to estimate these values by some > software rather than by rule of thumb. Do you know whether there is > such a tool anyway? > > In Freesurfer there is a tool included that is called optseq2. It is > described as follows: > > “optseq2 is a tool for automatically scheduling events for > rapid-presentation event-related (RPER) fMRI experiments (the schedule > is the order and timing of events). Events in RPER are presented > closely enough in time that their hemodynamic responses will overlap. > This requires that the onset times of the events be jittered in order > to remove the overlap from the estimate of the hemodynamic response. > RPER is highly resistant to habituation, expectation, and set because > the subject does not know when the next stimulus will appear or which > stimulus type it will be. RPER is also more efficient than > fixed-interval event related (FIER) because more stimuli can be > presented within a given scanning interval at the cost of assuming > that the overlap in the hemodynamic responses will be linear. In SPM > parlance, RPER is referred to as 'stochastic design'. The flexibility > of RPER means that there are a huge number of possible schedules, and > they are not equal. optseq2 randomly samples the space of possible > schedules and returns the 'best' one, where the user can control the > definition of 'best'. Cost functions include: average efficiency, > average variance reduction factor (VRF), and a weighted combination of > average and stddev of the VRF. The user can also specify that the > first order counter-balancing of the sequence of event-types be > pre-optimized.” > > Will it do the job? After a first try, I guess that optseq2 may not > allow constraints such that Response is always followed by Feedback. > > Could you please give me a hint how to setup durations of Fixation and > the ITI in an optimal way? > > Best wishes from Dresden, > Daniel > > ::::::::::::::::::::::::::::::::::::::::: > > Dipl.-Inf. Daniel Geisler > Wissenschaftlicher Mitarbeiter > Bereich Angewandte Entwicklungsneurowissenschaften > Klinik und Poliklinik für Kinder- und Jugendpsychiatrie und > -psychotherapie > Tel. +49 (0)351 458-7071 > Fax +49 (0)351 458-7206 > > Universitätsklinikum Carl Gustav Carus > an der Technischen Universität Dresden > Anstalt des öffentlichen Rechts des Freistaates Sachsen > Fetscherstraße 74 (Haus 25, Raum 233A), 01307 Dresden > http://www.uniklinikum-dresden.de > Vorstand: Prof. Dr. med. D. M. Albrecht (Sprecher), Wilfried E. B. Winzer > Vorsitzender des Aufsichtsrates: Prof. Dr. med. Peter C. Scriba > USt.-IDNr.: DE 140 135 217, St.-Nr.: 201 145 00020 > > ------------------------------------------------------------------------ > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer -- Douglas N. Greve, Ph.D. MGH-NMR Center gr...@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422 Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting FileDrop: www.nmr.mgh.harvard.edu/facility/filedrop/index.html _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.
