1Synchronous, but not asynchronous, multisensory stimulation has been 2 successfully employed to manipulate the experience of body ownership, as in the 3 case of the rubber hand illusion. Hence, it has been assumed that the rubber 4 hand illusion is bound by the same temporal rules as in multisensory integration. 5However, empirical evidence of a direct link between the temporal limits on the 6 rubber hand illusion and those on multisensory integration is still lacking. Here 7 we provide the first comprehensive evidence that individual susceptibility to the 8 rubber hand illusion depends upon the individual temporal resolution in 9 multisensory perception, as indexed by the temporal binding window. In 10 particular, in two studies we showed that the degree of temporal asynchrony 11 necessary to prevent the induction of the rubber hand illusion depends upon the 12 individuals' sensitivity to perceiving asynchrony during visuo-tactile stimulation. 13That is, the larger the temporal binding window, as inferred from a simultaneity 14 judgment task, the higher the level of asynchrony tolerated in the rubber hand 15 illusion. Our results suggest that current neurocognitive models of body 16 ownership Introduction 23Body representation has been linked to the processing and integration of 24 multisensory signals (for reviews: (Blanke, 2012; Ehrsson, 2012). An 25 outstanding example of the pivotal role played by multisensory mechanisms in 26 body representation is the Rubber Hand Illusion (RHI; (Blanke, 2012; Botvinick 27 & Cohen, 1998; Ehrsson, 2012). This illusion is generated when temporally close 28 visual and tactile events occur on a visible rubber hand and the hidden 29 that the subjective ratings of the illusion and the proprioceptive drift were 67 significantly higher for short delays, up to 300 msec. In the present study we do a 68 step forward by formally associating sensitivity to the rubber hand illusion to 69 temporal sensitivity in multisensory integration. Such a finding would foster new 70 Costantini et al. Page 5 of 32investigations into the temporal unfolding of body ownership, an issue largely 71 neglected so far. 72In order to achieve this, we measured participants' TBWs through the use of a 73 simultaneity judgment task, employing visual and tactile stimuli. Next, in the 74 same participants, and employing the same stimuli, we measured susceptibility 75 to the RHI in the synchronous and asynchronous conditions. Importantly, in the 76 asynchronous condition we individualized the amount of asynchrony (i.e. 77Stimulus Onset Asynchrony, SOA) between the visual and the tactile stimuli, 78 based on the individuals' TBW. This means that the individuals' own TBW was 79 used to establish the asynchrony between the visual stimulus delivered on the 80 rubber hand and the tactile stimulus delivered on the participants' real hand. In 81 more detail, rather than using standard large asynchronies, as used in previous 82 research ( Tsakiris & Haggard, 2005) (usually up to 1000 ms), we selected, at th...

Temporal encoding is a key feature in multisensory processing that leads to the integration versus segregation of perceived events over time. Whether or not two events presented at different offsets are perceived as simultaneous varies widely across the general population. Such tolerance to temporal delays is known as the temporal binding window (TBW). It has been recently suggested that individual oscillatory alpha frequency (IAF) peak may represent the electrophysiological correlate of TBW, with IAF also showing a wide variability in the general population (8–12 Hz). In our work, we directly tested this hypothesis by measuring each individual's TBW during a visuotactile simultaneity judgment task while concurrently recording their electrophysiological activity. We found that the individual's TBW significantly correlated with their left parietal IAF, such that faster IAF accounted for narrower TBW. Furthermore, we found that higher prestimulus alpha power measured over the same left parietal regions accounted for more veridical responses of non-simultaneity, which may be explained either by accuracy in perceptual simultaneity or, alternatively, in line with recent proposals by a shift in response bias from more conservative (high alpha power) to more liberal (low alpha power). We propose that the length of an alpha cycle constrains the temporal resolution within which perceptual processes take place.

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One of the most important ability of our brain is to integrate input from different sensory modalities to create a coherent representation of the environment. Does expectation affect such multisensory integration? In this paper, we tackled this issue by taking advantage from the crossmodal congruency effect (CCE). Participants made elevation judgments to visual target while ignoring tactile distractors. We manipulated the expectation of the tactile distractor by pairing the tactile stimulus to the index finger with a high-frequency tone and the tactile stimulus to the thumb with a low-frequency tone in 80% of the trials. In the remaining trials we delivered the tone and the visual target, but the tactile distractor was omitted (Study 1). Results fully replicated the basic crossmodal congruency effect. Strikingly, the CCE was observed, though at a lesser degree, also when the tactile distractor was not presented but merely expected. The contingencies between tones and tactile distractors were reversed in a follow-up study (Study 2), and the effect was further tested in two conceptual replications using different combinations of stimuli (Studies 5 and 6). Two control studies ruled out alternative explanations of the observed effect that would not involve a role for tactile distractors (Studies 3, 4). Two additional control studies unequivocally proved the dependency of the CCE on the spatial and temporal expectation of the distractors (Study 7, 8). An internal small-scale meta-analysis showed that the crossmodal congruency effect with predicted distractors is a robust medium size effect. Our findings reveal that multisensory integration, one of the most basic and ubiquitous mechanisms to encode external events, benefits from expectation of sensory input.

Tying the hands behind the back has detrimental effects on sensorimotor perceptual tasks. Here we provide evidence that beta band oscillatory activity in a resting state condition might play a crucial role in such detrimental effects. EEG activity at rest was measured from thirty young participants (mean age = 24.03) in two different body posture conditions. In one condition participants were required to keep their hands freely resting on the table. In the other condition, participants' hands were tied behind their back. Increased beta power was observed in the left inferior frontal gyrus during the tied hands condition compared to the free hands condition. A control experiment ruled out alternative explanations for observed change in beta power, including muscle tension. Our findings provide new insights on how body postural manipulations impact on perceptual tasks and brain activity.