Nakano Waka, Yokoyama Satoshi, Sato Hiroshi
Division of Humanities and Social Sciences, Graduate School of Humanities and Social Sciences, Hiroshima University, Higashihiroshima, JPN.
Department of Humanities, Faculty of Humanities, Niigata University, Niigata, JPN.
Cureus. 2024 Dec 8;16(12):e75351. doi: 10.7759/cureus.75351. eCollection 2024 Dec.
Background and aim Subthreshold depression is a potential risk factor for major depressive disorder. Although the neurobiological mechanism underlying major depressive disorder is well-established, the mechanism underlying subthreshold depression has not yet been fully elucidated. We investigated the characteristics of brain abnormalities in participants with subthreshold depression using near-infrared spectroscopy (NIRS) owing to its portability. Methods A total of 53 college students were recruited, and all participants performed three tasks: self-referential task (SRT), verbal fluency task (VFT), and category fluency task (CFT). Hemodynamic changes in the prefrontal cortex (PFC) during the tasks were also measured using NIRS. A generalized linear model was employed for the NIRS data analysis. Subsequently, we evaluated the relationship between depressive severity and NIRS data during task performance. Results Our analysis revealed a positive correlation between hemodynamic changes in the right PFC during the SRT and depression severity (SRTL_coeff: 0.12), suggesting that increased activation in this region may be associated with higher levels of depressive severity. In contrast, hemodynamic changes in the left PFC during the SRT did not significantly influence the severity of depression. Additionally, hemodynamic changes during the VFT and CFT did not significantly influence the severity of depression. Conclusions Hyperactivation of the right PFC, which is a characteristic of subthreshold depression, may cause a negative bias, leading to high sensitivity to negative stimuli. These results provide novel insights into the neural mechanism of subthreshold depression and highlight the utility of NIRS for evaluating brain function related to negative bias in the right PFC.
背景与目的 阈下抑郁是重度抑郁症的一个潜在风险因素。尽管重度抑郁症的神经生物学机制已得到充分确立，但阈下抑郁的潜在机制尚未完全阐明。由于近红外光谱技术（NIRS）具有便携性，我们使用该技术研究了阈下抑郁参与者大脑异常的特征。方法 共招募了53名大学生，所有参与者都执行了三项任务：自我参照任务（SRT）、言语流畅性任务（VFT）和类别流畅性任务（CFT）。还使用NIRS测量了任务期间前额叶皮层（PFC）的血流动力学变化。采用广义线性模型对NIRS数据分析。随后，我们评估了任务执行期间抑郁严重程度与NIRS数据之间的关系。结果 我们的分析显示，SRT期间右侧PFC的血流动力学变化与抑郁严重程度呈正相关（SRTL_coeff：0.12），这表明该区域激活增加可能与更高水平的抑郁严重程度相关。相比之下，SRT期间左侧PFC的血流动力学变化对抑郁严重程度没有显著影响。此外，VFT和CFT期间的血流动力学变化对抑郁严重程度也没有显著影响。结论 右侧PFC的过度激活是阈下抑郁的一个特征，可能会导致负性偏差，从而对负性刺激产生高敏感性。这些结果为阈下抑郁的神经机制提供了新的见解，并突出了NIRS在评估与右侧PFC负性偏差相关的脑功能方面的实用性。
