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Akimitsu SUDA1, 2), Nobutaka HATTORI2), Koji KAMAGATA3), Shigeki AOKI3), Seiki KONISHI1)2)Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan3)Department of Radiology, Juntendo University, School of Medicine, Tokyo, Japan1)Department of Neurophysiology, Juntendo University School of Medicine, Tokyo, JapanUta FUJIMOTO1), Akitoshi OGAWA1), Takahiro OSADA1), Masaki TANAKA1), Inhibition in Right Ventral Inferior Frontal Cortex208Corresponding author: Seiki KonishiDepartment of Neurophysiology, Juntendo University School of Medicine2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, JapanTEL: +81-3-5802-1026　E-mail: skonishi@juntendo.ac.jpResearch of the 5th Alumni Scientific Award for Medical Student, Juntendo University School of Medicine〔Received　Jan. 5, 2022〕〔Accepted　Jan. 21, 2022〕J-STAGE Advance published date: Apr. 15, 2022Copyright © 2022 The Juntendo Medical Society. This is an open access article distributed under the terms of Creative Commons Attribution License (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original source is properly credited. doi: 10.14789/jmj.JMJ21-0055-OTJuntendo Medical Journal2022. 68(3), 208-211Key words: inferior frontal gyrus, inferior frontal junction, boundary mappingPerspectiveNetwork Centrality Analysis Characterizes Brain Activity during Response The right inferior frontal cortex (IFC) plays a critical role in response inhibition1, 2). It has also been demonstrated that the IFC is heterogeneous and that the ventral part of the IFC (vIFC) is more critical to inhibition of prepotent response tendency. Recent areal parcellation analyses based on rest-ing-state functional connectivity have revealed that the right vIFC consists of multiple functional areas. Resting-state functional connectivity analyses have enabled parcellation of the cerebral cortex into functional areas based on their connectivity patterns3-5). Parcellation analyses have revealed multiple areas (parcels) in the vIFC3-5), suggesting functional heterogeneity within the vIFC. In the present study, we characterized the parcellated areas (parcels) in the right vIFC using graph-the-oretic analysis, which characterizes local connec-tivity properties of a brain network by referring to its global structure of functional connectivity. This abstract is based on a study first reported in Neuro-science6).Twenty right-handed subjects (10 men and 10 women, aged 26.6 ± 9.2 years (mean ± SD)) partic-ipated in the experiments. The experimental proce-dures were approved by the Institutional Review Board. Written informed consent was obtained from all subjects. Functional magnetic resonance imaging (fMRI) scans were acquired during resting state and during the performance of a stop-signal task1, 7). We used multi-band gradient-echo echo-planar sequences for functional images (TR = 1.0 sec, TE = 30 msec, flip angle = 62 deg, FOV = 192 × 192 mm2, matrix size = 96 × 96, 78 contiguous slices, voxel size = 2.0 × 2.0 × 2.0 mm3, multi-band factor = 6).For the resting-state dataset, preprocessing was conducted mainly following the pipelines of Human Connectome Project. The parcellation analyses based on boundary mapping were applied to the cerebral cortical surface. For subsequent analyses, to avoid non-uniform signal to noise ratio caused by the different number of vertices in the parcels, we defined regions of interest (ROIs) of 40 vertices closest to the centroid of each parcel. When the parcel contained less than 40 vertices, the ROI