[pymvpa] Help with analysis design

Raúl Hernández raul at lafuentelab.org
Tue Mar 10 21:40:12 UTC 2015

Hi, I'm having problems thinking about how to analyze my data and I was
wondering if any of you could give me some assistance.

I want to determine if the activity generated from a visual cue is the same
as the activity generated by a somatosensory stimulus. So I design a
discrimination task in which the participant receives a visual cue, then
touches the stimulus and presses a button to determine if the cue matched
with the somatosensory stimulus.

This is the design of a single block (in seconds):

0-12 baseline

12-16 visual cue

16-20 stimulus

20-22 response

Now, I have 4 categories of stimulus. I want to analyze the activity to
know whether there is a pattern that can be associated with each stimulus
category. I have 4 different visual cues that should elicitate the same
pattern as the actual stimulus. I need to categorize each event in order to
proceed with the analysis but if I assign the same 4 categories to the
visual cues then I'm already biasing the data. If I divide the data to
train the classifier with the stimulus and then test it with the visual
cues I think that due to the closeness of the events, the activity related
to the stimulus might be biased due to the previous cue.

I would really appreciate any suggestions
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