Inferior parietal lobule controls moral thought-action fusion: an fMRI study
Eunji Kim1, Sang Won Lee2, Hyunsil Cha1, Kyungeun Jang1, Heajung Choi1, Seungho Kim1, Jinsu Park1, Jiung Yang1,3, Huijin Song4, Moon Jung Hwang5, Hui Joong Lee6, Seung Jae Lee2, and Yongmin Chang1,6

1Department of Medical & Biological Engineering, Kyungpook National University, Daegu, Korea, Republic of, 2Department of Psychiatry, Kyungpook National University Hospital, Daegu, Korea, Republic of, 3Daegu Gyungpook Medical Innovation Foundation, Daegu, Korea, Republic of, 4Institue of Biomedical Engjneering Research, Kyungpook National University, Daegu, Korea, Republic of, 5GE Health Korea, Seoul, Korea, Republic of, 6Department of Radiology, College of Medicine, Kyungpook National University, Daegu, Korea, Republic of


Thought-action fusion (TAF) could make people feel that action to happen1. We investigated the difference from control thinking and administration of electrical shocks to another person in healthy control with moral related TAF task by using fMRI. The inferior parietal lobule (IPL) activation showed a negative correlation with moral score in TAF among the activated regions from a shock factor. Therefore, when considering the functional role of IPL in making another have some irritation and the appropriate empathic response, such as mentalization, might have an important role in TAF related situation.


Thought-action fusion represents a tendency to treat thinking and action as equivalent. TAF task may contribute to the transformation of normal intrusions into obsessive intrusions. In the present study, we used fMRI to assess the suffering mechanism from making another person be shocked in control using TAF task.


Thirty-two healthy subjects (23.87 ± 1.13 years) participated in this study. All participants were right-handed and carried out some questionnaire before and after fMRI scan. All participants received written informed consent and the study protocol was approved by the Institutional Review Board at Kyungpook National University Hospital. Each participant conducted the TAF task during the fMRI acquisition 2 and subjects responded degree of reminding. TAF task was consisted of four conditions which have shock/no-shock and suppressed/unsuppressed factors. The red sign of lightning informed an electrical shock which made another person irritated to the subjects. For example, condition 2 showed “Think of apples as little as possible.” with red lightning sign and let subjects be obligated to suppress thinking of “apple” and make another person have an electrical shock. fMRI data were acquired using a 3.0T GE DISCOVERY scanner (EPI, TR=2000ms, TE=30ms, FOV=23 cm, Matrix=64x64, Thickness=4.0mm, no gap). Image preprocessing and statistical analysis for fMRI data were performed using MATLAB and SPM12. The overall pre-processed fMRI data processed full factorial analysis to confirm the effect of shock and suppression factor at uncorrected P<0.001. One-way ANOVA test analyzed behavioral data using SPSS software.

Results and Discussion

Lingual gyrus, fusiform gyrus, middle occipital cortex, insula, precuneus, middle frontal gyrus, and inferior parietal lobule (IPL) showed significant activation in the main effect of shock (Figure 1). We performed post-hoc analysis to confirm the effect of shock and it showed that most regions were activated without any suppression about thinking. (Figure 2). IPL was activated when subjects did not have any suppression about thinking but have unpleasant situation which made another irritated. Additionally, IPL negatively correlated with moral TAF score (Figure 3). In our study, TAF responses induce activities in brain regions related to emphatic responses. Anterior insular which is related to emotional empathy was activated when individual thought induce painful response to others. Also, IPL was commonly activated in the theory of mind or mentalization related task 3. Mentalization was related to perspective taking ability that understands the viewpoint of another person’s experiences. Furthermore, appropriate activation in IPL may be related to reduce moral TAF responses. Our results suggest that an appropriate empathic response in TAF induce situation may have positive effects on mental health.


In our study, TAF-related task induces activity in the empathy-related brain regions. Specifically, IPL activation may be associated with TAF traits. Further clinical study requires more investigation to understand the role of TAF on the psychopathology.


No acknowledgement found.


1. National Institute of Mental Health (NIMH). Obsessive-compulsive Disorder: When Unwanted Thoughts or Irresistible Actions Take Over. NIH Publ No TR 16-4676. 2016.

2. Rassin E, Merckelbach H, Muris P, Spaan V. Thought-action fusion as a causal factor in the development of intrusions. Behav Res Ther. 1999;37(3):231-237. doi:10.1016/S0005-7967(98)00140-5

3. Hillis AE. Inability to empathize: Brain lesions that disrupt sharing and understanding another’s emotions. Brain. 2014;137(4):981-997. doi:10.1093/brain/awt317


Figure 1. Main effect of Shock map from 2x2 Full Factorial Analysis (uncorrected p<0.001 with cluster threshold 20.)

Figure 2. Positive effect of shock map. (A) without suppression about thinking of apples, (B) with suppression about thinking. (uncorrected p<0.001 with cluster threshold 20).

Figure 3. Moral factor of Thought-Action Fusion questionnaire has negative correlation with beta-value from inferior parietal lobule.

Proc. Intl. Soc. Mag. Reson. Med. 27 (2019)