# Resting-State Functional Connectivity in Mathematical Expertise

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## Abstract

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## 1. Introduction

## 2. Materials and Methods

#### 2.1. Participants

#### 2.2. Resting-State fMRI Acquisition

^{2}, 128 sagittal slices, spatial resolution = 1 × 1 × 1.5 m

^{3}, two acquisitions). A T2*-weighted gradient-echo echo-planar imaging (EPI) sequence was used (TR = 2000 ms, TE = 30 ms, flip angle = 90°, field of view (FOV) = 64 × 64 m

^{2}, 30 slices, resolution: 3 × 3 × 4 m

^{3}, interslice gap = 0.8 mm, 420 volumes). The scanning time was 14 min, and participants were required to watch a fixation lying still in the scanner.

#### 2.3. Resting-State fMRI Data Analysis

## 3. Results

#### 3.1. Functional Connectivity between Mathematicians and Non-Mathematicians

#### 3.2. Linking Functional Connectivity to Mathematics Scores

#### 3.3. Classification Performance

## 4. Discussion

#### 4.1. Resting-State Functional Connectivity for Detecting Group-Specific Features

#### 4.2. Functional Connectivity in Mathematicians

#### 4.3. Mathematicians’ Preconfigured Functional Connectivity for Their Expertise

#### 4.4. Neural Efficiency Correlated with the Functional Connectivity in the Caudate Nucleus

#### 4.5. Classification Accuracy

#### 4.6. Limitations

## 5. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## Abbreviations

## References

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**Figure 1.**Significant differences between mathematicians and non-mathematicians in terms of functional connectivity (independent permutation t-test, p < 0.01). (

**A**) Increased functional connectivity in mathematicians compared to non-mathematicians. (

**B**) Increased functional connectivity in non-mathematicians compared to mathematicians. Line width is defined based on inverted p-values (1/p). Dots indicate 22 pairs of ROIs for mathematicians (A) and 24 pairs of ROIs for non-mathematicians (B). Left and right views of ROI pairs show sagittal images and top view demonstrates an axial image.

**Figure 2.**Connectivity of the top-ten ROI pairs selected from Table 2. ROI pairs are denoted with circles connected to one another for (

**A**) the mathematician group and (

**B**) the non-mathematician group.

**Figure 3.**The relationship between the mathematics scores and the functional connectivity (normalized r values) between the bilateral caudate nucleus in the mathematicians. X-axis indicates the mathematicians’ scores in the standardized mathematics test and the Y-axis indicates the functional connectivity values between the left and right caudate nucleus using Pearson’s correlation coefficients. A significant negative correlation was found only in the mathematician group.

**Figure 4.**Classification accuracy with respect to the number of features. The maximum classification accuracy of 90.91% was obtained when using 39 features, which is denoted by an asterisk.

Mathematicians | Non-Mathematicians | Statistics | |
---|---|---|---|

Age | 33.42 (5.62) | 27.23 (8.21) | p = 0.081 |

Gender, M/F | 16/5 | 14/9 | p = 0.276 |

Handedness, LQ | 92.45 (3.65) | 90.28 (8.25) | p = 0.269 |

Years of education | 19.5 (2.7) | 16.21 (6.28) | p = 0.079 |

Mathematics test | 70.95 (7.13) | 40.71 (7.69) | p < 0.001 |

Intelligence test | 115.91 (12.35) | 124.27 (15.23) | p = 0.072 |

WM (forward) | 8.9 (3.12) | 9.12 (4.2) | p = 0.319 |

WM (backward) | 7.3 (1.9) | 7.62 (1.59) | p = 0.273 |

**Table 2.**List of region of interest (ROI) pairs showing statistically significant differences between mathematicians and non-mathematicians in terms of functional connectivity.

1st ROI | 2nd ROI | p-Value |
---|---|---|

Mathematicians > Non-mathematicians | ||

Left lateral orbital gyrus (LOrG) | Left triangular part of the inferior frontal gyrus (TrIFG) | 0.0003 |

Right ventral diencephalon (VDc) | Right frontal pole (FP) | 0.0011 |

Left ventral diencephalon (VDc) | Left superior frontal gyrus (SFG) | 0.0019 |

Left caudate nucleus (CN) | Right opercular part of the inferior frontal gyrus (OpIFG) | 0.0021 |

Left parahippocampal gyrus (PhG) | Right supplementary motor cortex (SMC) | 0.0031 |

Left caudate nucleus (CN) | Right inferior occipital gyrus (IOG) | 0.0039 |

Right pallidum (Pd) | Left inferior temporal gyrus (ITG) | 0.0039 |

Left middle cingulate gyrus (MCG) | Right temporal pole (TP) | 0.0039 |

Left putamen (Pu) | Left frontal pole (FP) | 0.0041 |

Right orbital part of the inferior frontal gyrus (OrIFG) | Left planum temporale (PT) | 0.0041 |

Left putamen | Left inferior temporal gyrus | 0.0051 |

Left ventral diencephalon | Right frontal pole | 0.0051 |

Right postcentral gyrus | Left precentral gyrus | 0.0059 |

Left fusiform gyrus | Left planum temporale | 0.0061 |

Left anterior orbital gyrus | Left occipital pole | 0.0061 |

Right putamen | Left frontal pole | 0.0063 |

Left lateral orbital gyrus | Right triangular part of the inferior frontal gyrus | 0.0065 |

Left frontal pole | Left posterior orbital gyrus | 0.0065 |

Right occipital pole | Right planum temporale | 0.0069 |

Right putamen | Right medial orbital gyrus | 0.0073 |

Left amygdala | Right medial frontal cortex | 0.0079 |

Right middle temporal gyrus | Left temporal pole | 0.0081 |

Non-Mathematicians > Mathematicians | ||

Left lateral orbital gyrus (LOrG) | Right precuneus (Pcun) | 0.000 |

Right thalamus (Th) | Right lateral orbital gyrus (LOrG) | 0.0007 |

Left thalamus (Th) | Right lateral orbital gyrus (LOrG) | 0.0011 |

Right middle occipital gyrus (MOG) | Right supplementary motor cortex (SMC) | 0.0017 |

Right middle occipital gyrus (MOG) | Left middle occipital gyrus (MOG) | 0.0021 |

Left gyrus rectus (GRe) | Right precuneus (Pcun) | 0.0027 |

Right postcentral gyrus (PcG) | Right superior occipital gyrus (SOG) | 0.0031 |

Right medial frontal cortex (MFC) | Right precuneus (Pcun) | 0.0033 |

Right caudate nucleus (CN) | Right planum temporale (PT) | 0.0037 |

Left medial frontal cortex (MFC) | Right precuneus (Pcun) | 0.0041 |

Right ventral diencephalon | Right fusiform gyrus | 0.0050 |

Right caudate nucleus | Left middle cingulate gyrus | 0.0053 |

Left lateral orbital gyrus | Left precuneus | 0.0061 |

Right caudate nucleus | Left anterior insula | 0.0067 |

Right lingual gyrus | Left lingual gyrus | 0.0067 |

Left precentral gyrus | Left middle temporal gyrus | 0.0069 |

Left inferior temporal gyrus | Left precentral gyrus | 0.0069 |

Left ventral diencephalon | Right fusiform gyrus | 0.0075 |

Right gyrus rectus | Right precuneus | 0.0081 |

Right hippocampus | Right inferior occipital gyrus | 0.0089 |

Right caudate nucleus | Right supramarginal gyrus | 0.0091 |

Right caudate nucleus | Left caudate nucleus | 0.0093 |

Right calcarine cortex | Right lingual gyrus | 0.0099 |

Right frontal pole | Right posterior orbital gyrus | 0.0099 |

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**MDPI and ACS Style**

Shim, M.; Hwang, H.-J.; Kuhl, U.; Jeon, H.-A.
Resting-State Functional Connectivity in Mathematical Expertise. *Brain Sci.* **2021**, *11*, 430.
https://doi.org/10.3390/brainsci11040430

**AMA Style**

Shim M, Hwang H-J, Kuhl U, Jeon H-A.
Resting-State Functional Connectivity in Mathematical Expertise. *Brain Sciences*. 2021; 11(4):430.
https://doi.org/10.3390/brainsci11040430

**Chicago/Turabian Style**

Shim, Miseon, Han-Jeong Hwang, Ulrike Kuhl, and Hyeon-Ae Jeon.
2021. "Resting-State Functional Connectivity in Mathematical Expertise" *Brain Sciences* 11, no. 4: 430.
https://doi.org/10.3390/brainsci11040430