Melbourne School of Psychological Sciences, The University of Melbourne, Melbourne, Victoria, Australia.
Australian Research Council Centre of Excellence for Integrative Brain Function, Clayton, Victoria, Australia.
Hum Brain Mapp. 2023 Apr 15;44(6):2557-2571. doi: 10.1002/hbm.26230. Epub 2023 Feb 22.
Anxiety can alter an individual's perception of their external sensory environment. Previous studies suggest that anxiety can increase the magnitude of neural responses to unexpected (or surprising) stimuli. Additionally, surprise responses are reported to be boosted during stable compared to volatile environments. Few studies, however, have examined how learning is impacted by both threat and volatility. To investigate these effects, we used threat-of-shock to transiently increase subjective anxiety in healthy adults while they performed an auditory oddball task under stable and volatile environments and while undergoing functional Magnetic Resonance Imaging (fMRI) scanning. We then used Bayesian Model Selection (BMS) mapping to identify the brain areas where different models of anxiety displayed the highest evidence. Behaviourally, we found that threat-of-shock eliminated the accuracy advantage conferred by environmental stability over volatility. Neurally, we found that threat-of-shock led to attenuation and loss of volatility-attuning of brain activity evoked by surprising sounds across most subcortical and limbic regions including the thalamus, basal ganglia, claustrum, insula, anterior cingulate, hippocampal gyrus and the superior temporal gyrus. Taken together, our findings suggest that threat eliminates learning advantages conferred by statistical stability compared to volatility. Thus, we propose that anxiety disrupts behavioural adaptation to environmental statistics, and that multiple subcortical and limbic regions are implicated in this process.
焦虑可以改变个体对外界感官环境的感知。先前的研究表明,焦虑可以增加对意外(或惊喜)刺激的神经反应幅度。此外,与不稳定环境相比,在稳定环境中报告的惊喜反应会增强。然而,很少有研究探讨威胁和波动性如何共同影响学习。为了研究这些影响,我们在健康成年人进行听觉Oddball 任务时,使用电击威胁来暂时增加主观焦虑,同时在稳定和不稳定环境下进行功能磁共振成像(fMRI)扫描。然后,我们使用贝叶斯模型选择(BMS)映射来确定不同焦虑模型显示最高证据的大脑区域。行为上,我们发现电击威胁消除了环境稳定性相对于波动性带来的准确性优势。神经上,我们发现电击威胁导致丘脑、基底神经节、屏状核、脑岛、前扣带、海马回和颞上回等大多数皮质下和边缘区域的大脑活动对惊喜声音的波动性调节减弱和丧失。总之,我们的发现表明,与波动性相比,威胁消除了统计稳定性带来的学习优势。因此,我们提出焦虑会破坏对环境统计数据的行为适应,并且多个皮质下和边缘区域参与了这个过程。