VA San Diego Healthcare System Center of Excellence for Stress and Mental Health, University of California, San Diego, United States.
VA San Diego Healthcare System Center of Excellence for Stress and Mental Health, University of California, San Diego, United States.
J Affect Disord. 2019 Oct 1;257:607-614. doi: 10.1016/j.jad.2019.07.050. Epub 2019 Jul 10.
Suicide is a significant health concern among veterans, and suicidal ideation is a common and functionally debilitating condition that frequently precedes suicidal behavior. Characterizing neurobiological substrates associated with suicidal ideation in veterans may inform evaluation of risk for this population. Associations between suicidal ideation and functional abnormalities in prefrontal, temporal, and striatal regions supporting cognitive task performance have been documented in individuals with mood and psychotic disorders, suggesting a potential role for neurocognitive vulnerabilities in this condition. To date, however, relatively little research has explored neural correlates of suicidal ideation, particularly among individuals with posttraumatic stress disorder (PTSD).
Twenty three combat veterans diagnosed with PTSD completed an adapted Reading Span (Rspan) working memory task during functional magnetic resonance imaging (fMRI). Participants were classified based on presence of current SI. We evaluated differences between these groups on neural activation in response to interference-based working memory demands within the task. Primary analyses were conducted using a voxel-wise between-group t-test.
Task-based activations were observed in regions including the cingulate, middle frontal, parietal, and occipital cortex, striatum, and cerebellum. Relative to individuals without SI, individuals with SI demonstrated less activation in a large region spanning the lateral prefrontal cortex and cingulate cortex, as well as the inferior temporal cortex, in response to interference demands.
Results are consistent with models proposing that prefrontal neural substrates involved in cognitive regulation are implicated in suicidal ideation. Involvement of temporal functioning may also exist based on current findings. Future research is needed to understand whether disturbances in prefrontal regulatory control reflect a specific profile subtype with distinct neural correlates, and how such neural patterns may be used to improve detection and treatment personalization.
自杀是退伍军人面临的一个严重健康问题，而自杀意念是一种常见且功能失调的状况，通常先于自杀行为。描述与退伍军人自杀意念相关的神经生物学基础可以为评估该人群的风险提供信息。在患有心境和精神病性障碍的个体中，已经记录了与支持认知任务表现的前额叶、颞叶和纹状体区域的功能异常相关的自杀意念，这表明神经认知脆弱性在这种情况下可能发挥作用。然而，迄今为止，相对较少的研究探讨了自杀意念的神经相关性，特别是在患有创伤后应激障碍（PTSD）的个体中。
23 名被诊断患有 PTSD 的参战退伍军人在功能磁共振成像（fMRI）期间完成了改编的阅读跨度（Rspan）工作记忆任务。参与者根据当前 SI 的存在进行分类。我们评估了这些组在任务中对干扰型工作记忆需求的神经激活方面的差异。主要分析使用组间的体素-wise t 检验进行。
在任务中观察到激活的区域包括扣带回、中额、顶叶和枕叶皮质、纹状体和小脑。与没有 SI 的个体相比，有 SI 的个体在响应干扰需求时，在横跨外侧前额叶皮质和扣带回皮质以及颞下回的大片区域中表现出较少的激活。
结果与提出涉及认知调节的前额叶神经基质与自杀意念有关的模型一致。根据当前的发现，颞叶功能障碍也可能存在。需要进一步研究以了解前额叶调节控制的干扰是否反映了具有独特神经相关性的特定亚类，以及如何利用这些神经模式来提高检测和治疗的个性化。
