Dear Yasuhiro,
>When I 'plot' the event-related responses using SPM 97, it asks me 'Which
>events?.'
>What does the 'events' mean in this case? (I'm analyzing a simple
>event-related task.
>Only one kind of event is presented to the subject repetitively.)
In a simple event related design, one could look at the evoked hemodynamic
response for a single event(type). I think your study is an example for that.
In more complicated designs one could also make inferences about differential
responses between different events. That is the reason why SPM asks you which
event you want to plot.
In the SPM event related kit, you are prompted for the event you want to plot.
In a single subject, single session design, this is straightforward. However,
if you have more than one session, SPM does not show you a mean of the events
you want over sessions.
An example:
If you have two sessions and events 1 and 2 in both
sessions, you can plot events 1, 2, 3 and 4, where events 3 and 4 are events 1
and 2 of session 2.
-Christian
--
Dr. C. Buechel
Research Fellow
Functional Imaging Laboratory
Wellcome Dept. of Cognitive Neurology
12 Queen Square
WC1N 3BG London
UK
Tel.: +44-171-833-7483
Fax.: +44-171-813-1420
email: [log in to unmask]
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