Harı Emre, Demiralp Tamer
Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istanbul University, Istanbul, Türkiye.
Hulusi Behcet Life Sciences Research Laboratory, Neuroimaging Unit, Istanbul University, Istanbul, Türkiye.
Noro Psikiyatr Ars. 2025 Jul 17;62(3):228-233. doi: 10.29399/npa.28785. eCollection 2025.
Novelty processing is one of the basic survival mechanisms for living organisms. Among the various types of novelty, stimulus novelty is the effect created by stimuli that are unlikely to be encountered throughout one's lifetime. However, the oddball design mostly used in studying stimulus novelty also includes an obligatory contextual novelty effect, which actually requires the presence of schemas about sensory input in the memory. In this study, we aimed to investigate the neural circuits related purely to the detection of stimulus novelty using functional magnetic resonance imaging (fMRI) by applying an experimental design that excludes any contextual novelty effect.
Fifteen right-handed healthy participants were included in the study. The stimulus novelty effect was generated by the images of object-like structures that could not be named and did not correspond to a real object. These stimuli were shuffled with images of familiar objects frequently encountered in daily life. SPM12 and CONN were used for the preprocessing stages and activation analysis of fMRI data. In the analyses, the cluster formation threshold was determined as p <0.001 and the cluster level significance threshold with family-wise error (FWE) correction was set at pFWE <0.05.
The activity of the fusiform, middle occipital, inferior occipital and superior occipital gyri increased during the processing of the stimulus novelty, while the activity of the inferior parietal cortex and supramarginal gyrus decreased.
With the experimental paradigm that excluded the confounding effects of contextual novelty, anatomical regions that respond specifically to stimulus novelty could be identified. Our results suggest that, while stimulus novelty intensively activates brain areas related with higher-order visual processing, the brain regions that associate sensory inputs with the schemas in the memory are less active.
新奇性处理是生物体的基本生存机制之一。在各种类型的新奇性中，刺激新奇性是由一生中不太可能遇到的刺激所产生的效应。然而，在研究刺激新奇性时最常用的异常球设计也包括一种强制性的情境新奇性效应，这实际上需要记忆中存在关于感觉输入的模式。在本研究中，我们旨在通过应用一种排除任何情境新奇性效应的实验设计，使用功能磁共振成像（fMRI）来研究与纯粹检测刺激新奇性相关的神经回路。
15名右利手健康参与者纳入本研究。刺激新奇性效应由无法命名且与真实物体不对应的类物体结构图像产生。这些刺激与日常生活中经常遇到的熟悉物体图像混合。使用SPM12和CONN进行fMRI数据的预处理阶段和激活分析。在分析中，聚类形成阈值确定为p<0.001，采用家族性错误（FWE）校正的聚类水平显著性阈值设定为pFWE<0.05。
在处理刺激新奇性期间，梭状回、枕中回、枕下回和枕上回的活动增加，而下顶叶皮质和缘上回的活动减少。
通过排除情境新奇性混杂效应的实验范式，可以识别出对刺激新奇性有特异性反应的解剖区域。我们的结果表明，虽然刺激新奇性强烈激活与高阶视觉处理相关的脑区，但将感觉输入与记忆中的模式相关联的脑区活动较少。
