The multisensory attentional consequences of tool use: a functional magnetic resonance imaging study
Authors: Peter C Hansen
Gemma A Calvert
Clare E Mackay
Charles Spence
Nicholas P Holmes
Journal: PLoS ONE (2008)
Discipline: Multidisciplinary
Keywords: Tool use; Multisensory integration; Spatial attention; Vibrotactile stimuli; Visual processing
Affiliations: Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom. 

Abstract:  Background: Tool use in humans requires that multisensory information is integrated across different locations, from objects seen to be distant from the hand, but felt indirectly at the hand via the tool. We tested the hypothesis that using a simple tool to perceive vibrotactile stimuli results in the enhanced processing of visual stimuli presented at the distal, functional part of the tool. Such a finding would be consistent with a shift of spatial attention to the location where the tool is used. Methodology/principal findings: We tested this hypothesis by scanning healthy human participants' brains using functional magnetic resonance imaging, while they used a simple tool to discriminate between target vibrations, accompanied by congruent or incongruent visual distractors, on the same or opposite side to the tool. The attentional hypothesis was supported: BOLD response in occipital cortex, particularly in the right hemisphere lingual gyrus, varied significantly as a function of tool position, increasing contralaterally, and decreasing ipsilaterally to the tool. Furthermore, these modulations occurred despite the fact that participants were repeatedly instructed to ignore the visual stimuli, to respond only to the vibrotactile stimuli, and to maintain visual fixation centrally. In addition, the magnitude of multisensory (visual-vibrotactile) interactions in participants' behavioural responses significantly predicted the BOLD response in occipital cortical areas that were also modulated as a function of both visual stimulus position and tool position. Conclusions/significance: These results show that using a simple tool to locate and to perceive vibrotactile stimuli is accompanied by a shift of spatial attention to the location where the functional part of the tool is used, resulting in enhanced processing of visual stimuli at that location, and decreased processing at other locations. This was most clearly observed in the right hemisphere lingual gyrus. Such modulations of visual processing may reflect the functional importance of visuospatial information during human tool use. 

Retracted: No

PubPeer comments:
 This paper was criticised as part of a self-reflection posted on Twitter on 2nd-3rd April, 2021 (twitter TheHandLab status 1377760796130869248) Criticism: These were my first fMRI experiments and paper. The design was not optimal for fMRI and it was based too much on my previous behavioural experiments 70471-4). The effects we report are weak, there were no significant activations in a whole-brain analysis I relied on a somewhat post-hoc region-of-interest analysis to report the weak effects. I doubt that these results would replicate (indeed, a very similar and unpublished follow-up experiment without using tools, did not replicate these effects), or, more importantly, that they are adequate to really answer the question. The central question for my PhD work was: Are the effects of tool use on the processing of multisensory (visual-tactile) information best interpreted as due to peripersonal space or spatial attention . The peripersonal space account predicted activity in posterior parietal and or frontal (premotor) regions, while the spatial attention account predicted relatively low-level changes in visual processing areas (following-on from Macaluso Driver s work). Overall, the study should have been designed more specifically to compare these two hypotheses, with clearly-defined brain regions in advance, and positive evidence that the manipulations were effective independent of the critical test. ,