Fast Periodic Stimulation (FPS): A Highly Effective Approach In fMRI Brain Mapping

Abstract

Functional magnetic resonance imaging (fMRI) is a major technique for human brain mapping. We present a Fast Periodic Stimulation (FPS) fMRI approach, demonstrating its high effectiveness in defining category-selective brain regions. Observers see a dynamic stream of widely variable natural object images alternating at a fast rate (6 images/sec). Every 9 seconds, a short burst of variable face images contrasting with objects in pairs induces an objective 0.111 Hz face-selective neural response in the ventral occipito-temporal cortex and beyond. A model-free Fourier analysis achieves a two-fold increase in signal-to-noise ratio compared to a conventional block-design approach with identical stimuli. Periodicity of category contrast and random variability among images minimize low-level visual confounds while preserving naturalness of the stimuli, leading to the highest values (80-90%) of test-retest reliability yet reported in this area of research. FPS-fMRI opens a new avenue for understanding brain function with low temporal resolution methods.\n\nHighlightsFPS-fMRI achieves a two-fold increase in peak SNR over conventional approach\n\nFPS-fMRI reveals comprehensive extended face-selective areas including ATL\n\nFPS-fMRI achieves high specificity by minimizing influence of low-level visual cues\n\nFPS-fMRI achieves very high test-retest reliability (80%-90%) in spatial activation map\n\neTOC BlurbIn Brief\n\nGao et al. present a novel FPS-fMRI approach, which achieves a two-fold increase in peak signal-to-noise ratio in defining the neural basis of visual categorization while preserving ecological validity, minimizing low-level visual confounds and reaching very high (80%-90%) test-retest reliability.