Comparison of auditory fMRI protocols for a voice localizer

<ns4:p>Auditory functional magnetic resonance imaging (fMRI) presents unique challenges due to scanner noise interference, which can limit the detection of stimulus-related brain activity. This study systematically evaluates five different fMRI protocols—continuous, sparse, fast sparse, clustered sparse, and interleaved silent steady state (ISSS)—to determine their effectiveness in capturing auditory and voice-related brain activity under identical scanning conditions. Participants passively listened to vocal and non-vocal sounds during fMRI protocols of the same duration, and the ability of each protocol to detect auditory and voice-specific activation was evaluated. Results showed that continuous imaging produced the largest and highest auditory activation, followed closely by clustered sparse sampling. Both sparse and fast sparse sampling yielded intermediate results, with fast sparse sampling performing better at detecting voice-specific activation. ISSS had the lowest activation sensitivity. The results highlight that continuous imaging is optimal when participants are well protected from scanner noise, while clustered sparse sequences offer the best alternative when stimuli are to be presented in silence.</ns4:p>