Case Control Study
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World J Psychiatry. May 19, 2022; 12(5): 693-707
Published online May 19, 2022. doi: 10.5498/wjp.v12.i5.693
Altered thalamic subregion functional networks in patients with treatment-resistant schizophrenia
Woo-Sung Kim, Jie Shen, Uyanga Tsogt, Soyolsaikhan Odkhuu, Young-Chul Chung
Woo-Sung Kim, Jie Shen, Uyanga Tsogt, Soyolsaikhan Odkhuu, Young-Chul Chung, Department of Psychiatry, Jeonbuk National University, Jeon-ju 54907, South Korea
Author contributions: Chung YC conceptualized the study; Tsogt U, Shen J, Kim WS, Odkhuu S, and Chung YC performed the study and acquired data; Kim WS conducted experiment and statistical analysis; Kim WS drafted the manuscript; Tsogt U, Shen J, Kim WS, and Odkhuu critically reviewed the manuscript; Chung YC finalized the manuscript; all authors approved the final manuscript.
Supported by the Korean Mental Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea, No. HL19C0015; and the Korea Health Technology R&D Project through the Korea Health Industry Development Institute, funded by the Ministry of Health & Welfare, Republic of Korea, No. HR18C0016.
Institutional review board statement: The study was approved by the Ethics Committee of Jeonbuk National University Hospital (approval number: CUH 2012-08-001).
Informed consent statement: All patients gave informed consent.
Conflict-of-interest statement: No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
Data sharing statement: No additional data are available.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Young-Chul Chung, MD, PhD, Professor, Department of Psychiatry, Jeonbuk National University, 20, Geonji-ro, Deokjin-gu, Jeonju-si, Jeollabuk-do, Republic of Korea, Jeon-ju 54907, South Korea. chungyc@jbnu.ac.kr
Received: September 28, 2021
Peer-review started: September 28, 2021
First decision: November 17, 2021
Revised: November 25, 2022
Accepted: April 2, 2022
Article in press: April 2, 2022
Published online: May 19, 2022
Processing time: 231 Days and 23.2 Hours
ARTICLE HIGHLIGHTS
Research background

The thalamus is an important deep gray matter structure that transmits sensory information from the peripheral sensory nervous system to the cortex, and serves as a major hub for cognitive processes. Previous studies treated the thalamus as a homogeneous structure, averaging blood oxygen level-dependent signals across the entire thalamus. However, this approach may fail to capture disturbances in specific networks, so it is necessary to investigate functional connectivity (FC) between sub-regions of the thalamus and cortex to better understand altered neural circuits in Schizophrenia (SZ).

Research motivation

To the best of our knowledge, no study has examined the FC of thalamic sub-regions in patients with treatment-resistant schizophrenia (TRS).

Research objectives

To identify the neural mechanisms underlying TRS. We hypothesized that the FC of thalamic sub-regions with cortical networks and voxels would differ between TRS patients and HCs (Healthy Controls).

Research methods

This study included 111 subjects (50 patients with TRS and 61 HCs). The rs-fMRI and sMRI data were obtained at the Jeonbuk National University Hospital using a 3T Verio scanner (Magnetom Verio; Siemens, Erlangen, Germany) with a 12-channel standard quadrature head coil. The functional parcellation atlas was used to segment the thalamus into nine subregions. FC analysis was performed between thalamic ROIs and cortical functional network ROIs, within the nine thalamic and nine cortical functional network ROIs, and between the thalamic ROIs and all cortical voxels. Demographic and clinical data were compared between the two groups using a two-sample t-test or Chi-square test. For partial correlation analysis. Relationships between the extracted Z-scores and PANSS scores were analyzed using age, sex, and FD as covariates.

Research results

There were no significant differences in age, sex, or education level between the two groups. We found differences in FC within thalamic subregions and cortical functional networks between patients with TRS and HCs. In addition, increased FC was observed between thalamic subregions and the sensorimotor cortex, frontal medial cortex, and lingual gyrus. These abnormalities were associated with the pathophysiology of TRS.

Research conclusions

The thalamus represents the interface between the sensory and motor systems, and is a major hub for cognitive processes. A large body of evidence has demonstrated the involvement of the thalamus in the pathophysiology of SZ. we found altered FC between various thalamic subregions, between various cortical functional networks, and between thalamic subregions and various cortical regions. These abnormalities were associated with overall pathophysiology. Collectively, these results suggest that disrupted FC within thalamic and cortical functional networks, and within the thalamocortical pathway, could serve as markers for TRS.

Research perspectives

This study improves our understanding of the relationships between the thalamocortical pathway and symptoms of TRS.