Altered multisensory temporal integration in obesity.

Federica Scarpina,Daniele Migliorati,Alessandro Mauro,Marcello Costantini,Massimo Scacchi,Paolo Marzullo

doi:10.1038/srep28382

Abstract

Eating is a multisensory behavior. The act of placing food in the mouth provides us with a variety of sensory information, including gustatory, olfactory, somatosensory, visual, and auditory. Evidence suggests altered eating behavior in obesity. Nonetheless, multisensory integration in obesity has been scantily investigated so far. Starting from this gap in the literature, we seek to provide the first comprehensive investigation of multisensory integration in obesity. Twenty male obese participants and twenty male healthy-weight participants took part in the study aimed at describing the multisensory temporal binding window (TBW). The TBW is defined as the range of stimulus onset asynchrony in which multiple sensory inputs have a high probability of being integrated. To investigate possible multisensory temporal processing deficits in obesity, we investigated performance in two multisensory audiovisual temporal tasks, namely simultaneity judgment and temporal order judgment. Results showed a wider TBW in obese participants as compared to healthy-weight controls. This holds true for both the simultaneity judgment and the temporal order judgment tasks. An explanatory hypothesis would regard the effect of metabolic alterations and low-grade inflammatory state, clinically observed in obesity, on the temporal organization of brain ongoing activity, which one of the neural mechanisms enabling multisensory integration.

Highlights

Only recently preliminary results were reported by Wan and colleagues[17]
The results showed a wider TBW in obese participants (Mean = 663 ms, STD = 128 ms) as compared to healthy-weight controls (Mean = 496 ms, STD = 149; t(37) =−3.73; p < 0.001; 95% CI [−257; −76]) (See Fig. 2)
The results showed a higher just noticeable difference (JND) in obese participants (Mean = 196 ms; STD = 90 ms) as compared to healthy-weight controls (Mean = 129 ms; STD = 75 ms; t(1, 38) =−3,18; p < 0.003; 95% CI [−0327; −0.07]) (See Fig. 3)

Summary

Introduction

Only recently preliminary results were reported by Wan and colleagues[17]. They showed that obese people tend to respond more slowly to multisensory stimulation in an audiotactile discrimination task than underweight people. In this study we evaluated the TBW in obese participants and healthy weight control subjects using both the SJ and TOJ task We used both tasks as they imply different perceptual and/or cognitive operations. While SJ task requires a low-level analysis of stimuli in terms of temporal relationships, TOJ task implies additional processing steps following the lower-level analyses of temporal relationships. Despite such dissimilarity, the two tasks share a common underlying process responsible for the ascription of temporal identity at a stimuli[26]. Such common characteristic allows us to genuinely measure temporal features of multisensory integration in obesity

Methods

Results

Conclusion