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Single- and multiple-event paradigms for identification of motor cortex activation
M Marquart1, R Birn, V Haughton
1Department of Radiology, Medical College of Wisconsin, Milwaukee, USA.
AJNR. American Journal of Neuroradiology
|February 11, 2000
Summary
The single-event functional MRI technique is a useful alternative to block-trial methods for detecting sensorimotor cortex activation during tongue and toe movements, especially when head motion is a concern. However, the block-trial method generally yields more precise activation in primary motor areas for finger tasks.
Area of Science:
- Neuroimaging
- Functional Magnetic Resonance Imaging (fMRI)
- Motor Neuroscience
Background:
- The single-event technique offers an alternative to block-trial methods for fMRI studies, particularly when head motion may accompany neural activation.
- Detecting sensorimotor cortex activation during motor tasks is crucial for understanding brain function.
Purpose of the Study:
- To compare the efficacy of single-event and block-trial fMRI paradigms in measuring sensorimotor cortex activation.
- To evaluate the impact of head motion on activation detection using both methods.
Main Methods:
- Six participants performed finger, tongue, and toe motor tasks under both block-trial and single-event fMRI paradigms.
- Activation was detected using cross-correlation and classified within the sensorimotor cortex, supplementary motor area (SMA), or as nonspecific.
- Statistical analysis involved t-tests to compare differences between the two acquisition paradigms (P < .05).
Main Results:
- Both methods identified activation for finger and tongue tasks; the toe task showed inconsistent results.
- Increased motion artifact was observed with tongue and toe tasks compared to finger tasks.
- The single-event method identified more activated pixels on average, but the block-trial method yielded a higher percentage of pixels specifically localized to the sensorimotor cortex or SMA.
Conclusions:
- The single-event paradigm is a valuable alternative to the block-trial method for detecting sensorimotor cortex or SMA activation during tongue and toe movements, which are prone to head motion.
- Neither method demonstrated a superior percentage of activation within primary motor areas across all tasks.
- For finger movements, which typically involve less head motion, the block-trial method generally provided a greater percentage of specific sensorimotor cortex or SMA activation.