Poster No:
581
Submission Type:
Abstract Submission
Authors:
Idy Wing Yi Chou1, Hanna LU1, Arthur DP Mak2, Linda Chiu Wa Lam3
Institutions:
1The Chinese University of Hong Kong, Hong Kong SAR, China, 2University of Cambridge, London, United Kingdom, 3The Chinese University of Hong Kong, Hong Kong, Hong Kong
First Author:
Co-Author(s):
Hanna LU
The Chinese University of Hong Kong
Hong Kong SAR, China
Introduction:
This study aimed to investigate multi-scale gray matter (GM) alterations in young, unmedicated individuals with bipolar II depression (BPII) and unipolar depression (UD) compared to healthy controls (HC) using gray matter volume, cortical thickness, pial surface area, and local gyrification index measures.
Methods:
The study included 27 individuals with BPII (mean age = 23.1), 27 individuals with UD (mean age = 24.0), and 27 HC (mean age = 23.1). All patients were unmedicated and clinically depressed as assessed by the Montgomery‐Åsberg Depression Rating Scale (MADRS). High-resolution structural magnetic resonance imaging (MRI) scans were acquired. Freesurfer was used for image preprocessing and extraction of GM volume, cortical thickness, pial surface area, and local gyrification index (LGI). The Desikan-Killiany atlas was used for cortical parcellation for ROI-based analysis. Vertex-wise analysis was performed for LGI.
Results:
Our findings revealed significant GM alterations in both BPII and UD compared to HC. Individuals with BPII exhibited lower cortical thickness at right superior parietal cortex compared to HC (p = 0.03), while UD displayed reduced cortical thickness at right caudal anterior cingulate cortex (p = 0.002) and posterior cingulate cortex (p = 0.03) compared to HC. Additionally, BPII showed higher LGI at the right middle temporal cortex (ROI-based analysis; p = 0.03) and right precentral cortex (vertex-wise analysis; p = 0.04) compared to UD.
Conclusions:
Conclusions: Our study provides evidence of extensive GM alterations in BPII and UD across multi-scale measures. These findings are clinically significant. Firstly, the two groups of patients exhibited distinctive patterns of structural changes, indicative of possible early detection of the BPII and UD using these neuromarkers. Secondly, our findings in young, unmedicated adults with BPII and UD suggest that the observed structural alterations are not solely attributable to medication effects, but occur early in the course of the illness. Indeed, cortical thinning is known to be associated with illness course and symptom burden, such as the number of hypomanic episodes (Abe et al., 2022). Early intervention targeting the identified brain regions may hold promise in mitigating or preventing these pathological processes. This is particularly significant because existing research on high-risk cohorts typically does not show apparent gray matter changes (Hajek et al., 2015).
The observed structural differences are in line with the current understanding of the pathophysiological underpinnings of BPII and UD. Cortical thinning in the right superior parietal cortex in BPII is possibly associated with deficits in executive processes such as attention and working memory (Corbetta & Shulman, 2002), which are central to emotion regulation (Wadlinger & Isaacowitz, 2011). UD displayed reduced cortical thickness at the right cingulate cortex, which may imply impairments in emotional responses from the disrupted processing of reward and punishment information (Rolls, 2019) and emotional words (Maddock, Garrett, & Buonocore, 2003). Moreover, UD had reduced gyrification at the right middle temporal and precentral cortex compared to BPII, suggesting difficulties in interpreting and conveying emotional expression (Goghari, Macdonald, & Sponheim, 2011; Manelis, Huppert, Rodgers, Swartz, & Phillips, 2019). Future studies with larger sample sizes and collaborative efforts are warranted to confirm and extend our results.
Disorders of the Nervous System:
Psychiatric (eg. Depression, Anxiety, Schizophrenia) 1
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
Neuroanatomy Other 2
Keywords:
Affective Disorders
Cortex
DISORDERS
Morphometrics
MRI
Psychiatric Disorders
STRUCTURAL MRI
Other - Gray matter
1|2Indicates the priority used for review
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Corbetta, M., & Shulman, G. L. (2002). Control of goal-directed and stimulus-driven attention in the brain. Nat Rev Neurosci, 3(3), 201-215. doi:10.1038/nrn755
Goghari, V. M., Macdonald, A. W., 3rd, & Sponheim, S. R. (2011). Temporal lobe structures and facial emotion recognition in schizophrenia patients and nonpsychotic relatives. Schizophr Bull, 37(6), 1281-1294. doi:10.1093/schbul/sbq046
Maddock, R. J., Garrett, A. S., & Buonocore, M. H. (2003). Posterior cingulate cortex activation by emotional words: fMRI evidence from a valence decision task. Hum Brain Mapp, 18(1), 30-41. doi:10.1002/hbm.10075
Manelis, A., Huppert, T. J., Rodgers, E., Swartz, H. A., & Phillips, M. L. (2019). The role of the right prefrontal cortex in recognition of facial emotional expressions in depressed individuals: fNIRS study. J Affect Disord, 258, 151-158. doi:10.1016/j.jad.2019.08.006
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