Peripersonal Space from a multisensory perspective: the distinct effect of the visual and tactile components of Visuo-Tactile stimuli

Maddalena Beccherle,Michele Scandola,Francesca Villani,Marzia Zanini,Stefania Facchetti

doi:10.1007/s00221-022-06324-8

Maddalena Beccherle, Michele Scandola + Show 3 more

Open Access

https://doi.org/10.1007/s00221-022-06324-8

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Abstract

Peripersonal Space (PPS) is defined as the space close to the body where all interactions between the individual and the environment take place. Behavioural experiments on PPS exploit multisensory integration, using Multisensory Visuo-Tactile stimuli (MVT), whose visual and tactile components target the same body part (i.e. the face, the hand, the foot). However, the effects of visual and tactile stimuli targeting different body parts on PPS representation are unknown, and the relationship with the RTs for Tactile-Only stimuli is unclear. In this study, we addressed two research questions: (1) if the MVT-RTs are independent of Tactile-Only-RTs and if the latter is influenced by time-dependency effects, and (2) if PPS estimations derived from MVT-RTs depend on the location of the Visual or Tactile component of MVTs. We studied 40 right-handed participants, manipulating the body location (right hand, cheek or foot) and the distance of administration. Visual and Tactile components targeted different or the same body parts and were delivered respectively at five distances. RTs to Tactile-Only trials showed a non-monotonic trend, depending on the delay of stimulus administration. Moreover, RTs to Multisensory Visuo-Tactile trials were found to be dependent on the Distance and location of the Visual component of the stimulus. In conclusion, our results show that Tactile-Only RTs should be removed from Visuo-Tactile RTs and that the Visual and Tactile components of Visuo-Tactile stimuli do not necessarily have to target the same body part. These results have a relevant impact on the study of PPS representations, providing new important methodological information.

Highlights

The definition of Peri-Personal Space (PPS) changed over time, from the very first definitions strictly connected with the first pieces of evidence from single-neuron recordings (Fogassi et al 1996; Gentilucci et al 1983; Graziano et al 1999, 1994; Rizzolatti et al 1997, 1981), to the mounting behavioural and electrophysiological shreds of evidence in humans (Bufacchi and Iannetti 2018; Hunley and Lourenco 2018; Serino 2019).Communicated by Melvyn A
To the best of our knowledge, this study explicitly demonstrates for the first time, in the field of multisensory PPS that Reaction Times (RTs) to unimodal Tactile-Only stimuli are neither constant nor following a linear monotonic trend
Face- hand- and foot-centred PPS representations were assessed for the first time using an adapted version of the well known Multisensory Integration Task, administrating the Visual and Tactile components of stimuli to these three different body parts

Summary

Introduction

The definition of Peri-Personal Space (PPS) changed over time, from the very first definitions strictly connected with the first pieces of evidence from single-neuron recordings (Fogassi et al 1996; Gentilucci et al 1983; Graziano et al 1999, 1994; Rizzolatti et al 1997, 1981), to the mounting behavioural and electrophysiological shreds of evidence in humans (Bufacchi and Iannetti 2018; Hunley and Lourenco 2018; Serino 2019).Communicated by Melvyn A. The most recent definitions agree considering the PPS representation being a continuous space closely surrounding the body, somato-topically organized (Farnè and Làdavas 2000; Hyvarinen and Poranen 1974; Robinson and Burton 1980; Robinson et al 1978; Schicke et al 2009; Serino et al 2015; Stone et al 2017), in which reaching objects and interacting with the environment is possible without locomotion (Borghi and Cimatti 2010; Bufacchi and Iannetti 2018; di Pellegrino and Làdavas 2015; Serino 2019). An example is represented by the Multisensory Interaction Task (Serino 2019; Serino et al 2007). In this paradigm, participants are asked to respond as fast as possible to a tactile stimulation applied to a body part, while task-irrelevant stimuli (audio or visual) approach the same body part.

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