Changes in Structural Covariance among Olfactory-related Brain Regions in Anosmia Patients

Suji Lee, Yumi Song, Haejin Hong, Yoonji Joo, Eunji Ha, Youngeun Shim, Seung No Hong, Jungyoon Kim, In Kyoon Lyoo, Sujung Yoon, Dae Woo Kim

Research output: Contribution to journalArticlepeer-review


Anosmia, characterized by the loss of smell, is associated not only with dysfunction in the peripheral olfactory system but also with changes in several brain regions involved in olfactory processing. Specifically, the orbitofrontal cortex is recognized for its pivotal role in integrating olfactory information, engaging in bidirectional communication with the primary olfactory regions, including the olfactory cortex, amygdala, and entorhinal cortex. However, little is known about alterations in structural connections among these brain regions in patients with anosmia. In this study, high-resolution T1-weighted images were obtained from participants. Utilizing the volumes of key brain regions implicated in olfactory function, we employed a structural covariance approach to investigate brain reorganization patterns in patients with anosmia (n=22) compared to healthy individuals (n=30). Our structural covariance analysis demonstrated diminished connectivity between the amygdala and entorhinal cortex, components of the primary olfactory network, in patients with anosmia compared to healthy individuals (z=-2.22, FDR-corrected p=0.039). Conversely, connectivity between the orbitofrontal cortex—a major region in the extended olfactory network—and amygdala was found to be enhanced in the anosmia group compared to healthy individuals (z=2.32, FDR-corrected p=0.039). However, the structural connections between the orbitofrontal cortex and entorhinal cortex did not differ significantly between the groups (z=0.04, FDR-corrected p=0.968). These findings suggest a potential structural reorganization, particularly of higher-order cortical regions, possibly as a compensatory effort to interpret the limited olfactory information available in individuals with olfactory loss.

Original languageEnglish
Pages (from-to)99-106
Number of pages8
JournalExperimental Neurobiology
Issue number2
StatePublished - 30 Apr 2024

Bibliographical note

Publisher Copyright:
© 2024 Korean Society for Neurodegenerative Disease. All rights reserved.


  • Amygdala
  • Anosmia
  • Entorhinal cortex
  • Orbitofrontal cortex
  • Structural covariance analysis


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