Increased interhemispheric functional connectivity during non-dominant hand movement in right-handed subjects

Abstract

Hand preference is one of the behavioral expressions of lateralization in the brain. Previous fMRI studies showed the activation in several regions including the motor cortex and the cerebellum during single-hand movement. However, functional connectivity related to hand preference has not been investigated. Here, we used the generalized psychophysiological interaction (gPPI) approach to investigate the alteration of functional connectivity during single-hand movement from the resting state in right-hand subjects. The functional connectivity in interhemispheric motor-related regions including the supplementary motor area, the precentral gyrus, and the cerebellum was significantly increased during non-dominant hand movement, while functional connectivity was not increased during dominant hand movement. The general linear model (GLM) showed activation in contralateral supplementary motor area, contralateral precentral gyrus, and ipsilateral cerebellum during right- or left-hand movement. These results indicate that a combination of GLM and gPPI analysis can detect the lateralization of hand preference more clearly.

Keywords: Biological sciences; Neuroscience; Techniques in neuroscience.

Graphical abstract

Figure 1

Schematic figure of the experimental paradigm (A) The schematic figure of single-hand movement experiment. The “+” indicates the rest period. The “L” means the left-hand movement and the “R” means the right-hand movement. During the single-hand movement task, the subjects continued to open and close their fingers. The fMRI scanning was continued for 10 min and 30 s. (B) The schematic figure of fMRI without single-hand movement.

Figure 2

Significant increase of BOLD signal during single-hand movement (A) Significant BOLD increase during the right-hand movement (p < 0.05, family wise error (FWE)-corrected, N = 26). (B) The significant BOLD increase during the left-hand movement (p < 0.05, FWE-corrected, N = 26). (C) Significant difference between right-hand movement and left-hand movement (p < 0.05, FWE-corrected, N = 26). L, left; R, right. The color bar indicates the t-values. CO, central operculum; preCG, precentral gyrus; SMA, supplementary motor area.

Figure 3

Altered functional connectivity during the single left-hand movement (A) Brain and circle plots for all nodes during the left-hand movement. The gray line indicates the increased connectivity (p < 0.05, NBS-corrected, N = 26). (B) Significantly increased functional connectivity in the motor network during left-hand movement (p < 0.05, NBS-corrected, N = 26). The red line indicates the connectivity with the right inferior frontal gyrus operculum (IFGoper). The green line indicates the connectivity with the right precentral gyrus (preCG). The yellow line indicates the connectivity with the right supplementary motor area (SMA). The blue line indicates the connectivity with the right putamen. The purple line indicates the connectivity with the left SMA. (C) Brain and circle plots for all nodes during the left-hand movement. The gray line indicates the significantly decreased connectivity (p < 0.05, NBS-corrected, N = 26).

Figure 4

Altered functional connectivity during the single right-hand movement (A) Brain and circle plots for all nodes during the right-hand movement. The gray line indicates the significantly decreased functional connectivity (p < 0.05, NBS-corrected, N = 26). (B) Significant increase of functional connectivity during left-hand movement rather than right-hand movement (p < 0.05, NBS-corrected, N = 26).

Figure 5

Voxel-based gPPI analysis (A–F) Increased functional connectivity (A) with the left supplementary motor area (SMA), (B) with the right inferior frontal gyrus operculum (IFGoper), (C) with the right precentral gyrus (preCG), (D) with the putamen, (E) with the right anterior supramarginal gyrus (aSMG), and (F) with the posterior supramarginal gyrus (pSMG) during left-hand movement. p < 0.05, FEW-corrected, N = 26. Color bar, T-values. FO, frontal operculum; FP, frontal pole; IC, insular cortex; IFGoper, inferior frontal gyrus operculum; MFG, middle frontal gyrus; MPrG, Precentral gyrus medial segment; HG, Heschl’s gyrus; OP, occipital pole; PT, planum temporale; SFG, superior frontal gyrus; SMG, superior middle gyrus; STG, superior temporal gyrus; toMTG, temporo-occipital part of middle temporal gyrus.