21fMRI User Guide
Figure 14. Positioning scan for the EPI BOLD scan using finger tapping as the paradigm.
5. Ask subject to start finger tapping with his/her right hand, and then start the sequence.
6. The sequence will first run the prep scans. At the bottom left on the screen is a display that indicates what
part of the paradigm is running, baseline (“B”) or active (“A”), and the current measurement number (see
Figure 15). The counter increments as the scan progresses with the measurements.
The experiment starts with the display “B”, which indicates the Baseline state. In this experiment, we
have a paradigm size of 20, with 10 Baseline and 10 Active states. Therefore, measurements 1 through
10 will be Baseline, then 11 through 20 will be Active (which completes one set of the paradigm of 20
measurements), 21 through 30 will be Baseline again, 31 through 40 Active, and so on. Therefore, when the
10th measurement is completed and 11th is about to begin, the display switches from “B” to “A”, indicating
the “Active” part of the paradigm. This is your cue to ask the subject to switch the finger tapping hand from
right to left. Similarly, after the 20th measurement is completed, the display will switch from “A” to “B”, and
it is time to ask the subject to switch the finger tapping hand from left to right again. Keep repeating this
procedure until the scan is completed.
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