Arai Yu, Katagiri Naoyuki, Tagata Hiromi, Uchino Takashi, Saito Junichi, Shido Yusuke, Kamiya Kouhei, Hori Masaaki, Mizuno Masafumi, Nemoto Takahiro
Department of Neuropsychiatry, Toho University Graduate School of Medicine, Tokyo, Japan.
Department of Neuropsychiatry, Toho University Faculty of Medicine, Tokyo, Japan.
Front Psychiatry. 2024 Jun 13;15:1323786. doi: 10.3389/fpsyt.2024.1323786. eCollection 2024.
Aberrant fixation and scan paths in visual searches have been repeatedly reported in schizophrenia. The frontal eye fields (FEF) and thalamus may be responsible for fixation and scan paths. These two regions are connected by superior thalamic radiation (STR) in humans. Studies have reported reduced fixation numbers and shortened scan path lengths in individuals with attenuated psychosis syndrome (APS) and schizophrenia. In this study, we hypothesized that STRs in the white matter fiber bundles of impairments underlie abnormalities in fixation and scan path length in individuals with APS.
Twenty-one individuals with APS and 30 healthy controls participated in this study. All participants underwent diffusion tensor imaging, and fractional anisotropy (FA) values of the left and right STR were analyzed using the novel method TractSeg. The number of eye fixations (NEF), total eye scanning length (TESL), and mean eye scanning length (MESL), derived using the exploratory eye movement (EEM) test, were adopted to evaluate the fixation and scan path length. We compared the FA values of the bilateral STR and EEM parameters between the APS and healthy control groups. We investigated the correlation between bilateral STR and EEM parameters in the APS and healthy control groups.
NEF, TESL, MESL, and the FA values of the left STR were significantly reduced in individuals with APS compared to healthy controls. The left STR FA value in the APS group was significantly positively correlated with the MESL ( = 0.567, = 0.007). In addition, the right STR FA value of the APS group was significantly correlated with the TESL ( = 0.587, = 0.005) and MESL ( = 0.756, = 0.7×10).
These results demonstrate that biological changes in the STR, which connects the thalamus and FEF, underlie abnormalities in fixation and scanning. Recently, aberrations in the thalamus-frontal connection have been shown to underlie the emergence of psychotic symptoms. STR impairment may be a part of the biological basis of APS in individuals with subthreshold psychotic symptoms.
精神分裂症患者在视觉搜索中反复出现异常注视和扫描路径。额叶眼区（FEF）和丘脑可能负责注视和扫描路径。在人类中，这两个区域通过丘脑上辐射（STR）相连。研究报告称，处于精神病综合征（APS）缓解期的个体和精神分裂症患者的注视次数减少，扫描路径长度缩短。在本研究中，我们假设APS患者白质纤维束中的STR损伤是其注视和扫描路径长度异常的基础。
21名APS患者和30名健康对照者参与了本研究。所有参与者均接受了扩散张量成像，并使用新型方法TractSeg分析了左右STR的分数各向异性（FA）值。采用探索性眼动（EEM）测试得出的眼注视次数（NEF）、总眼扫描长度（TESL）和平均眼扫描长度（MESL）来评估注视和扫描路径长度。我们比较了APS组和健康对照组双侧STR的FA值和EEM参数。我们研究了APS组和健康对照组中双侧STR与EEM参数之间的相关性。
与健康对照组相比，APS患者的NEF、TESL、MESL以及左侧STR的FA值均显著降低。APS组左侧STR的FA值与MESL显著正相关（r = 0.567，p = 0.007）。此外，APS组右侧STR的FA值与TESL显著相关（r = 0.587，p = 0.005），与MESL也显著相关（r = 0.756，p = 7×10⁻⁴）。
这些结果表明，连接丘脑和FEF的STR中的生物学变化是注视和扫描异常的基础。最近的研究表明，丘脑 - 额叶连接异常是精神病症状出现的基础。STR损伤可能是具有阈下精神病症状个体APS生物学基础的一部分。
