Shuhama Rosana, Rondinoni Carlo, de Araujo Draulio Barros, de Freitas Caetano Gustavo, Dos Santos Antonio Carlos, Graeff Frederico Guilherme, Del-Ben Cristina Marta
Department of Neurosciences and Behavior, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
Image Sciences and Medical Physics Center Laboratory, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
Behav Brain Res. 2016 Oct 15;313:358-369. doi: 10.1016/j.bbr.2016.06.059. Epub 2016 Jul 22.
Functional neuroimaging studies have shown that actual situations of uncertain or distant threats increase the activity of forebrain regions, whereas proximal threats increase the activity of the dorsal midbrain. This experiment aimed at testing the hypothesis that brain activity elicited by imagined scenarios of threats with two different magnitudes, potential and imminent, resembles that found in response to actual threats. First, we measured subjective responses to imagined scenarios of potential and imminent threats compared with neutral and pleasant scenarios. The same scenarios were used as a paradigm in a functional magnetic resonance imaging experiment. Behavioral results show that the scenarios draw a gradient of hedonic valence and arousal dimensions. Both potential and imminent threat scenarios increased subjective anxiety; the imminent threat scenario also increased feelings of discomfort and bodily symptoms. The functional magnetic resonance imaging results revealed modulations of BOLD signal in the ventromedial prefrontal cortex by potential threat and in the periaqueductal gray matter by imminent threat. These results agree with previously reported evidence using actual threat situations, indicating that mental imagery is a reliable method for studying the functional neuroanatomy of relevant behavioral processes.
功能性神经影像学研究表明，不确定或遥远威胁的实际情况会增加前脑区域的活动，而近端威胁会增加中脑背侧的活动。本实验旨在检验以下假设：由潜在和迫在眉睫的两种不同程度威胁的想象情景引发的大脑活动，类似于对实际威胁的反应。首先，我们测量了与中性和愉快情景相比，对潜在和迫在眉睫威胁的想象情景的主观反应。相同的情景被用作功能磁共振成像实验的范式。行为结果表明，这些情景呈现出享乐效价和唤醒维度的梯度。潜在和迫在眉睫的威胁情景均增加了主观焦虑；迫在眉睫的威胁情景还增加了不适感和身体症状。功能磁共振成像结果显示，潜在威胁会调节腹内侧前额叶皮层的血氧水平依赖（BOLD）信号，而迫在眉睫的威胁会调节导水管周围灰质的BOLD信号。这些结果与先前使用实际威胁情景报告的证据一致，表明心理意象是研究相关行为过程的功能性神经解剖学的可靠方法。
