Most evidence on the neural and perceptual correlates of sensory processing derives from studies that have focused on only a single sensory modality and averaged the data from groups of 50 participants. Although valuable, such studies ignore the substantial inter-and intra-individual differences that are undoubtedly at play. Such variability plays an integral role in both the behavioral/perceptual realms and in the neural correlates of these processes, but substantially less is known when

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... ed with group-averaged data. Recently, it has been shown that the presentation of stimuli from two or more sensory modalities (i.e., multisensory stimulation) not only results in the well-established performance 55 gains, but also gives rise to reductions in behavioral and neural response variability. To better understand the relationship between neural and behavioral response variability under multisensory conditions, the present study investigated both behavior and brain activity in a task requiring subjects to discriminate moving versus static stimuli presented in either a unisensory or multisensory context. Electroencephalographic (EEG) data were analyzed with respect to intra-and inter-individual differences 60 in reaction times (RTs). The results showed that trial-by-trial variability of RTs was significantly reduced under audiovisual presentation conditions as compared to visual-only presentations across all participants. Intra-individual variability of RTs was linked to changes in correlated activity between clusters within an occipital to frontal network. Additionally, inter-individual variability of RTs was linked to differential recruitment of medial frontal cortices. The present findings highlight differences in the brain 65 networks that support behavioral benefits during unisensory vs. multisensory motion detection, and provide an important view into the functional dynamics within neuronal networks underpinning intraindividual performance differences.