06/06/2019
Nagoya University
Keio University
A research group led by Associate Professor Kazuya Motomura of the Department of Neurosurgery (Professor Toshihiko Wakabayashi) at Nagoya University Graduate School of Medical Sciences (Dean Kenji Kadomatsu), and Professor Satoshi Umeda and Associate Professor Yuri Terasawa of the Psychology Laboratory, Faculty of Letters, Keio University, has revealed the brain functional networks involved in emotion recognition through awake surgery on brain tumor patients.
The answer to the question of how neural networks in the brain function to recognize one's own emotions, such as happiness, sadness, and anger, remains unknown. Previous research, using neuropsychological methods on patients with brain damage and functional brain imaging analysis with functional MRI, has reported that the activity of the anterior insular cortex increases both when one is conscious of interoceptive sensations and when one subjectively feels emotions.
In this study, we analyzed the brain functional networks involved in emotion recognition by directly stimulating the insular cortex of patients with brain tumors involving this area during awake surgery, while they performed an expression recognition task (recognizing expressions such as anger, happiness, sadness, disgust, and neutral from photographs). Before, during (awake), and after surgery, we used the expression recognition task to examine the patients' ability to discriminate the type and intensity of emotions represented by facial expressions by asking them to report what they felt. During awake surgery, direct stimulation of the anterior insular cortex clearly enhanced the recognition of "anger." Furthermore, after resection of the insular cortex, the recognition of "anger" distinctly decreased, while conversely, the recognition of "sadness" increased. Moreover, Voxel-based lesion-symptom mapping (VLSM), a method for detailed examination of the relationship between lesion sites and symptoms, indicated that the recognition of anger is associated with the left insular cortex. These findings suggest that the insular cortex, as the neural basis of arousal based on interoceptive sensations (information from within the body), is involved in changes in the recognition of emotions such as anger and sadness.
The results of this research were published online in the international scientific journal "Brain Structure and Function" on June 5, 2019 (10:00 PM JST).
This research was supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS), specifically Grant-in-Aid for Scientific Research (B) (No. 24330210) and Grant-in-Aid for Scientific Research (C) (No. 17K10862).
For the full press release, please see below.