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More Sample FMRI Data Time Series
¥ Second: Event-related FMRI
H ÒActivationÓ occurs in single relatively brief intervals
H ÒEventsÓ can be randomly or regularly spaced in time
o If events are randomly spaced in time, signal model itself looks noise-like (to the human eye)
H BOLD response to stimulus tends to be weaker since fewer nearby-in-time ÒactivationsÓ have overlapping hemodynamic responses
¥ Next slide: Visual stimulation experiment
ÒActiveÓ voxel shown in next slide