Jo Cutler

Dear Dominik Thank you for your reply. The dispersion of the trials with very high amplitudes were very small. I have changed the minimum to 0.3 and this does reduce (approximately half) the very high amplitudes, although they are still much greater than the average. As most of my events of interest are flexible, what is the best way to put the amplitude and dispersion together? I can't see a way to extract the peaks of reconstructed responses from a DCM as there is with the GLM - have I missed something?...

Dear Dominik Thank you for your reply. The dispersion of the trials with very high amplitudes were very small. I have changed the minimum to 0.3 and this does reduce (approximately half) the very high amplitudes, although they are still much greater than the average. As most of my events of interest are flexible, what is the best way to put the amplitude and dispersion together? I can't see a way to extract the peaks of reconstructed responses from a DCM as there is with the GLM - have I missed something?...

Dear Dominik Thank you so much for your previous message and apologies for only just acknowledging it. I've now run multiple models and chosen one based on the RSS (which seems like a valid procedure as the same model came out best for the vast majority of participants and across 4 different tasks with similar trial structures but different content). I'm now examining the DCM amplitude estimates and have a few questions: 1) Are the units of these amplitudes in the native GSR recording units if the...

Hi Dominik Thanks for your ongoing support. That makes sense re. the DCM falling back on the prior as the model I sent was based on timings from before we discovered the anticipatory responses. To work out the best way to model the data, I've run DCMs with different timings to create, for example, a single flexible event across the anticipation and onset of a stimulus vs. two events - one for each of these parts. Is it valid to then use the trial-by-trial model fit statistics (blind to any experimental...

Hi Dominik Thanks so much for getting back to me so quickly. I'm experimenting with the FIR and extract segements now so will let you know if I find anything which seems odd. In terms of deciding what to model, is it better to be on the safe side and model everything e.g. (a) and (b) even if participants may be only responding to one event or is this costly for the model? It seems there might be individual differences between my participants in whether they show an anticipatory repsonse or not -...

Dear all Thank you for the software and previous support. We are looking at SCR data from a task (120 trials) where each trial consists of: a) 2sec (+/- 30 %) fixation cross b) presentation of a sentence containing information about a bad situation establishing uncertainty c) self-paced jitter to move on from this (cut off if participants take more than 7 seconds) d) 2.5sec (+/-30%) jittered anticipation (visually distinct from c) e) 0.5sec fixation cross f) outcome of the situation revealed and...

Dear all Thank you for the software and previous support. We are looking at SCR data from a task (120 trials) where each trial consists of: a) 2sec (+/- 30 %) fixation cross b) presentation of a sentence containing information about a bad situation establishing uncertainty c) self-paced jitter to move on from this (cut off if participants take more than 7 seconds) d) 2.5sec (+/-30%) jittered anticipation (visually distinct from c) e) 0.5sec fixation cross f) outcome of the situation revealed and...

Hi Please could someone provide me with more information about exactly how the normalization procedure works. In particular, how are the mean and standard deviation calculated? Is this from the whole data file in which case whether the datafile is trimmed to exclude breaks in stimulus presentation etc will make a difference or is it done after response values are extracted so only the data around markers are important. Also how does this work with excluded epochs? Are these ignored during the normalization?...