You may consider what is known as ‘hidden dummies’, which are not disclosed by the scanner, as opposed to the 'visible dummy scans'. Hidden dummies are hidden to the operator and may be 1 or 2, as it depends on the type of tissue chosen, and a different TR for those dummies may also be applied.
73, Peter
> On 11 Dec 2023, at 12:28, Ronald Sladky <[log in to unmask]> wrote:
>
> What Christophe posted sounds very plausible. It also depends on whether you have done slice-timing correction or not - and if so to what slice you aligned it to.
>
> Have a look at Figure 4: https://www.sciencedirect.com/science/article/pii/S1053811911007245?via%3Dihub#f0020
> Here you nicely see the reduced sensitivity in the motor cortex if the timing is off by 0.5-1 TR.
>
> Hope this helps,
> Ronny
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