1.A Review of Brain Imaging Studies on Classical Fear Conditioning and Extinction in Healthy Adults
Ilhyang KANG ; Chaewon SUH ; Sujung YOON ; Jungyoon KIM
Journal of the Korean Society of Biological Psychiatry 2021;28(2):23-35
Fear conditioning and extinction, which are adaptive processes to learn and avoid potential threats, have essential roles in the pathophysiology of anxiety disorders. Experimental fear conditioning and extinction have been used to identify the mechanism of fear and anxiety in humans. However, the brain-based mechanisms of fear conditioning and extinction are yet to be established. In the current review, we summarized the results of neuroimaging studies that examined the brain changes—functional activity and structures—regarding fear conditioning or extinction in healthy individuals. The functional activity of the amygdala, insula, anterior cingulate gyrus, ventromedial prefrontal cortex, and hippocampus changed dynamically with both fear conditioning and extinction. This review may provide an up-to-date summary that may broaden our understanding of pathophysiological mechanisms of anxiety disorder. In addition, the brain regions that are involved in the fear conditioning and extinction may be considered as potential treatment targets in the future studies.
2.A Review on Neuronavigated Repetitive Transcranial Magnetic Stimulation and Its Antidepressant Effect
Myeongju KIM ; Yumi SONG ; Chaewon SUH ; Jiyoung MA ; Gahae HONG ; Jungyoon KIM
Journal of the Korean Society of Biological Therapies in Psychiatry 2020;26(2):101-115
Repetitive transcranial magnetic stimulation (rTMS) is widely recognized as an effective and noninvasive neuromodulation for treating depression, and has been applied in a wide range of clinical settings. However, previous studies often reported inconsistent antidepressant effects that may be due to differences in the rTMS protocols such as coil placement. The typical simulation site for rTMS depression protocol is the left dorsolateral prefrontal cortex (DLPFC). Targeting the exact site of the left DLPFC while considering individual brain structure has been challenging due to the non-invasive nature of rTMS. Several researchers have applied various targeting methods to overcome the abovementioned issue. Most of the previous studies have applied the “5-cm rule” or the “international 10-20 system,” which is easily applicable. Recently, researchers started to apply a neuronavigation system that targets the stimulation site based on neuroimaging of each individual. Pros and cons of targeting methods have been discussed in terms of validity and reliability of targeting stimulation sites, differences in treatment responses, as well as considerations of individual characteristics. Therefore, the current review focuses on the targeting methods of stimulation site and the treatment effects of depression in previous studies. For discussion, we divided neuronavigation methods into using fixed coordinates and using individualized targets. Furthermore, the limitations of each targeting method are discussed that may potentially contribute to the development of the optimal rTMS protocol for depression treatment.
3.Aberrant Resting-state Functional Connectivity in Complex Regional Pain Syndrome: A Network-based Statistics Analysis
Haejin HONG ; Chaewon SUH ; Eun NAMGUNG ; Eunji HA ; Suji LEE ; Rye Young KIM ; Yumi SONG ; Sohyun OH ; In Kyoon LYOO ; Hyeonseok JEONG ; Sujung YOON
Experimental Neurobiology 2023;32(2):110-118
Complex regional pain syndrome (CRPS) is a chronic neuropathic pain disorder. Pain catastrophizing, characterized by magnification, rumination, and helplessness, increases perceived pain intensity and mental distress in CRPS patients. As functional connectivity patterns in CRPS remain largely unknown, we aimed to investigate functional connectivity alterations in CRPS patients and their association with pain catastrophizing using a whole-brain analysis approach. Twenty-one patients with CRPS and 49 healthy controls were included in the study for clinical assessment and resting-state functional magnetic resonance imaging. Between-group differences in whole-brain functional connectivity were examined through a Network-based Statistics analysis. Associations between altered functional connectivity and the extent of pain catastrophizing were also assessed in CRPS patients. Relative to healthy controls, CRPS patients showed higher levels of functional connectivity in the bilateral somatosensory subnetworks (components 1~2), but lower functional connectivity within the prefronto-posterior cingulate (component 3), prefrontal (component 4), prefronto-parietal (component 5), and thalamo-anterior cingulate (component 6) subnetworks (p<0.05, family-wise error corrected). Higher levels of functional connectivity in components 1~2 (β=0.45, p=0.04) and lower levels of functional connectivity in components 3~6 (β=-0.49, p=0.047) were significantly correlated with higher levels of pain catastrophizing in CRPS patients. Higher functional connectivity in the somatosensory subnetworks implicating exaggerated pain perception and lower functional connectivity in the prefronto-parieto-cingulo-thalamic subnetworks indicating impaired cognitive-affective pain processing may underlie pain catastrophizing in CRPS.
4.Alterations in Brain Morphometric Networks and Their Relationship with Memory Dysfunction in Patients with Type 2 Diabetes Mellitus
Rye Young KIM ; Yoonji JOO ; Eunji HA ; Haejin HONG ; Chaewon SUH ; Youngeun SHIM ; Hyeonji LEE ; Yejin KIM ; Jae-Hyoung CHO ; Sujung YOON ; In Kyoon LYOO
Experimental Neurobiology 2024;33(2):107-117
Cognitive dysfunction, a significant complication of type 2 diabetes mellitus (T2DM), can potentially manifest even from the early stages of the disease. Despite evidence of global brain atrophy and related cognitive dysfunction in early-stage T2DM patients, specific regions vulnerable to these changes have not yet been identified. The study enrolled patients with T2DM of less than five years’ duration and without chronic complications (T2DM group, n=100) and demographically similar healthy controls (control group, n=50). High-resolution T1-weighted magnetic resonance imaging data were subjected to independent component analysis to identify structurally significant components indicative of morphometric networks. Within these networks, the groups’ gray matter volumes were compared, and distinctions in memory performance were assessed. In the T2DM group, the relationship between changes in gray matter volume within these networks and declines in memory performance was examined. Among the identified morphometric networks, the T2DM group exhibited reduced gray matter volumes in both the precuneus (Bonferronicorrected p=0.003) and insular-opercular (Bonferroni-corrected p=0.024) networks relative to the control group. Patients with T2DM demonstrated significantly lower memory performance than the control group (p=0.001). In the T2DM group, reductions in gray matter volume in both the precuneus (r=0.316, p=0.001) and insular-opercular (r=0.199, p=0.047) networks were correlated with diminished memory performance. Our findings indicate that structural alterations in the precuneus and insular-opercular networks, along with memory dysfunction, can manifest within the first 5 years following a diagnosis of T2DM.
5.Sensitivity of Detecting Alpha-Synuclein Accumulation in the Gastrointestinal Tract and Tissue Volume Examined
Chaewon SHIN ; Seong-Ik KIM ; Sung-Hye PARK ; Jung Hwan SHIN ; Chan Young LEE ; Han-Kwang YANG ; Hyuk-Joon LEE ; Seong-Ho KONG ; Yun-Suhk SUH ; Han-Joon KIM ; Beomseok JEON
Journal of Movement Disorders 2022;15(3):264-268
Objective:
This study aimed to evaluate whether a larger tissue volume increases the sensitivity of detecting alpha-synuclein (AS) pathology in the gastrointestinal (GI) tract.
Methods:
Nine patients with Parkinson’s disease (PD) or idiopathic rapid eye movement sleep disorder (iRBD) who underwent GI operation and had full-depth intestinal blocks were included. All patients were selected from our previous study population. A total of 10 slides (5 serial sections from the proximal and distal blocks) per patient were analyzed.
Results:
In previous studies, pathologic evaluation revealed phosphorylated AS (+) in 5/9 patients (55.6%) and in 1/5 controls (20.0%); in this extensive examination, this increased to 8/9 patients (88.9%) but remained the same in controls (20.0%). The severity and distribution of positive findings were similar between patients with iRBD and PD.
Conclusion
Examining a large tissue volume increased the sensitivity of detecting AS accumulation in the GI tract.
6.Absence of Alpha-Synuclein Pathology in the Stomach of a Patient With Prodromal Dementia With Lewy Bodies
Chaewon SHIN ; Seong-Ik KIM ; Sung-Hye PARK ; Jung Hwan SHIN ; Chan Young LEE ; Han-Joon KIM ; Hyuk-Joon LEE ; Seong-Ho KONG ; Yun-Suhk SUH ; Han-Kwang YANG ; Beomseok JEON
Journal of Movement Disorders 2023;16(2):213-216