Karel -
I would check out Chawla et al (1999), Nature Neuroscience, 2, 671-676.
The trick is to ensure a large range of SOAs between events within a block,
to minimise the correlation between the event-related covariates and the
block-related covariates (which in turn requires longish blocks). The cost
of
being able to look at both effects is a loss in efficiency for detecting
each
effect alone (compared to a short-epoch, eg 20s, blocked design, or a short
stochastic SOA event-related design).
Rik
Karel Deblaere wrote:
> Dear SPM community,
>
> at the SPM course in Brighton last june, the possibility of a combined
> event-block design was mentioned in several talks. This design makes it
> possible to evaluate the stimuli in both an event and block design by
> separating the stimuli in one block of stimuli in such a way that an
> event-related analysis is also possible. I'm very interested in such a
> design but I have some practical questions.
> Does anyone have experience with this? Are there already references on
> this?
> Does anyone have an practical example of how to spread your stimuli in a
> block ?
> Is the power of an event-related analysis with this type of design as
> powerfull as with a typical randomized event related study (because the
> stimuli are kept together in blocks and are not as much separated as a
> normal event-ralated designs, I suppose).
>
> I hope some of you have answers on some of these questions,
>
> thanks in advance,
>
> Karel deblaere
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