Acheson Dean T, Eyler Lisa T, Resovsky Jesse, Tsan Elisa, Risbrough Victoria B
Department of Psychiatry, University of California San Diego, USA.
Department of Psychiatry, University of California San Diego, USA; Mental Illness Research, Education and Clinical Center, VA San Diego Healthcare System, USA.
J Affect Disord. 2015 Oct 1;185:230-8. doi: 10.1016/j.jad.2015.06.053. Epub 2015 Jul 21.
Affective dysregulation is a core feature of bipolar disorder (BD). Abnormalities in neural circuits underlying affect regulation have been observed in BD, specifically in the structure and function of the amygdala and orbital frontal cortex (OFC). Fear extinction is an automatic affect regulatory process relying on neural circuits that are abnormal in BD. Thus, fear extinction might be useful in probing automatic affect regulation deficits in BD. We tested the hypothesis that BD is associated with reduced ability to extinguish fear responses.
We examined fear conditioning, extinction, and extinction memory recall in a sample of stable, euthymic participants with BD (n=19) vs. healthy comparison participants (n=32). A limited number of subjects (BD: n=12; healthy comparison: n=11) underwent structural MRI scanning to examine cortical size associations with extinction recall.
Both healthy comparison and BD participants were successful in acquiring a fear response, but BD participants responded with greater startle to both threat and safety cues. Both groups showed significant extinction. The BD group showed superior extinction recall. Extinction recall was associated with right rostral middle frontal cortex thickness across groups, whereas right OFC surface area was associated with recall only in healthy comparisons.
Limitations include use of a stable, highly screened sample and a relatively small number of participants available for MRI analysis.
Increased fear reactivity may be related to a "trait" disruption in BD patients similar to that previously described in anxiety disorders. This task may be useful for probing automatic affect regulatory processes in BD, and understanding treatment response.
情感失调是双相情感障碍（BD）的核心特征。在双相情感障碍中已观察到情感调节相关神经回路的异常，特别是杏仁核和眶额皮质（OFC）的结构和功能异常。恐惧消退是一种依赖于双相情感障碍中异常神经回路的自动情感调节过程。因此，恐惧消退可能有助于探究双相情感障碍中自动情感调节缺陷。我们检验了双相情感障碍与恐惧反应消退能力降低相关的假设。
我们在一组稳定的、处于心境正常期的双相情感障碍患者（n = 19）与健康对照参与者（n = 32）样本中，研究了恐惧条件反射、消退及消退记忆回忆。对少数受试者（双相情感障碍组：n = 12；健康对照组：n = 11）进行了结构磁共振成像扫描，以检查皮质大小与消退回忆的关联。
健康对照组和双相情感障碍组参与者均成功获得恐惧反应，但双相情感障碍组参与者对威胁和安全线索的惊跳反应更大。两组均表现出显著的消退。双相情感障碍组表现出更好的消退回忆。跨组来看，消退回忆与右侧额中回喙部厚度相关，而右侧眶额皮质表面积仅在健康对照组中与回忆相关。
局限性包括使用的是稳定的、经过高度筛选的样本，以及可用于磁共振成像分析的参与者数量相对较少。
恐惧反应性增加可能与双相情感障碍患者中一种类似于先前在焦虑症中描述的“特质”性破坏有关。该任务可能有助于探究双相情感障碍中的自动情感调节过程，并理解治疗反应。
