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Hi, Steve.

I think it is a wise idea to include the 2nd order derivatives, particularly if your older adult cohort has a history of cardiac, statin use or hypertension-related issues.  Inclusion of these derivatives probably should also be guided by your task structure and event timing, but that’s a bit beyond my wheelhouse.

Hope this helps,
Jeff

Duke University Medical Center
Div. of Geriatric Behavioral Health


On Apr 29, 2020, at 2:25 PM, Steve Petersen <[log in to unmask]> wrote:

Dear SPM experts,

Please, could you give to me some suggestions about my previous email?.

Thanks for your time.

Best regards,

El mié., 22 abr. 2020 a las 17:11, Steve Petersen (<[log in to unmask]>) escribió:

Dear all,

I am conducting a fMRI study (event-related design) in old adults. As I understand, aging can induce changes in latency and amplitude of the haemodinamuc response (that´s right?).

Taking into account this, I was wondering if it is a good choice uses the Canonical HRF with time and dispersion derivatives in my first level. More generally speaking, in which cases is it advisable to include derivatives?

Thank you in advance.

Best regards,

Steve.