Postural Effects on the Mental Rotation of Body-Related Pictures: An fMRI Study.

Fangbing Qu,Yuan Zhong,Jianping Wang,Haosheng Ye

doi:10.3389/fpsyg.2018.00720

Abstract

This study investigated the embodied effects involved in the mental rotation of pictures of body parts (hands and feet). Blood oxygen level-dependent (BOLD) signals were collected from 18 healthy volunteers who performed mental rotation tasks of rotated drawings of hands under different arm postures. Congruent drawings of hands (those congruent with left-hand posture) evoked stronger activation in the left supplementary motor area (SMA), left precentral gyrus, and left superior parietal lobule (SPL) than did incongruent drawings of hands. Congruent drawings of hands (those congruent with right-hand posture) evoked significant activation in the left inferior parietal lobule (IPL), right SMA, bilateral middle frontal gyrus (MFG), left inferior frontal gyrus (IFG), and bilateral superior frontal gyrus (SFG) compared to that evoked by the incongruent drawings of hands. Similar methodology was implemented with drawings of feet. However, no significant differences in brain activation were observed between congruent and incongruent drawings of feet. This finding suggests that body posture influences body part-related mental rotation in an effector-specific manner. A direct comparison between the medially and laterally rotated drawings revealed activation in the right IPL, left precentral gyrus, bilateral IFG, and bilateral SFG. These results suggest that biomechanical constraints affect the cognitive process of mental rotation.

Highlights

Previous studies have suggested that mental simulations during spatial transformation tasks share common temporal and kinematic mechanisms with those involved in actual task performance (Shepard and Metzler, 1971; Parsons and Fox, 1998)
The results showed that when the left forearm was flexed, the congruent drawings were associated with strong activation in the supplementary motor area (SMA), superior parietal lobule (SPL), precentral gyrus, and superior frontal gyrus (SFG), all within the left hemisphere (p < 0.05, AlphaSim-corrected, t = 1.8125; Figure 4A and Table 1)
In-rotation Effect A paired t-test between the medial and lateral hand orientations showed increased Blood oxygen level-dependent (BOLD) signal (p < 0.05, AlphaSim-corrected, t = 1.8125) in the right inferior parietal lobule (IPL), bilateral SFG, bilateral inferior frontal gyrus (IFG), and left precentral gyrus (Figure 5). These results suggested that orientation influences brain activity in areas related to mental imagery, such as the IPL, SFG, and IFG because the in-rotation trials require more spatial working memory retrieval and greater motor-related attention to daily actions than to stored actions relevant to the current presented drawings than do trials involving unfamiliar hand rotations

Summary

Introduction

Previous studies have suggested that mental simulations during spatial transformation tasks share common temporal and kinematic mechanisms with those involved in actual task performance (Shepard and Metzler, 1971; Parsons and Fox, 1998). Previous behavior results have suggested a general pattern that participants’ response time in the laterality judgment task are proportional to the time taken by the participants to physically move their hands in the position of the hand-stimuli (Parsons and Fox, 1998) This type of task requires that participants engage in object-centered reference frames; subjects must first rotate the representation of the object to a new position and make a right or left laterality judgment. Numerous studies have demonstrated that both core and general motor areas are involved in this type of task, the supplementary motor area (SMA), precentral gyrus, inferior parietal lobule (IPL), superior parietal lobule (SPL), and premotor cortex (PMC) (Hanakawa et al, 2007; Hetu et al, 2013) These behavioral and imaging studies demonstrated that the process of mentally rotating body parts shares similar or even identical brain activity with that which occurs during the actual movement of that body part (de Lange et al, 2005)

Results

Discussion

Conclusion