Poster No:
1720
Submission Type:
Abstract Submission
Authors:
Anton Stenwall1, Aino-Linnea Uggla Kalvas1, David Weibust1, Markus Fahlström2, Mats Ryttlefors1, Francesco Latini1
Institutions:
1Department of Medical Sciences, Uppsala University, Uppsala, Uppland, 2Department of Radiology, Uppsala University, Uppsala, Uppland
First Author:
Co-Author(s):
David Weibust
Department of Medical Sciences, Uppsala University
Uppsala, Uppland
Introduction:
Olfaction is in many ways the least understood sensory modality. Olfactory system organization and connectivity is not fully elucidated (Allison, 1954)(Kavoi, 2011)(Lopéz-Elizalde, 2011). The aim of this study was to investigate the structural connectivity and organization of the olfactory system by using a fiber dissection technique and tractography.
Methods:
Ten cerebral hemispheres were used in this study for white matter dissection according to Klingler´s technique (Latini, 2015). DTI from twenty-five healthy individuals from the HCP dataset were used to explore the connectivity of the olfactory system using DSI Studio. White matter connectivity between 1) Olfactory bulb to primary olfactory cortices, 2) Olfactory bulb to secondary olfactory cortices, 3) Primary to secondary olfactory cortices were reconstructed with GQI algorithm. For each step both qualitative and quantitative results were documented. The DTI metrics of the identified major associative, projection and commissural pathways were subsequently correlated with olfactory function and cognition in seventy-five healthy individuals (NIH toolbox) with Spearman's rank correlation and Benjamini-Hochberg method for false discoveries (CI 95%,p<.05) using R.
Results:
The dissection showed that the lateral stria was significantly longer on the left side and projected towards the amygdala, the entorhinal and piriform cortex. The medial stria was not evident. Both dissection and tractography showed that major associative white matter pathways such as UF, IFOF and cingulum supported the connectivity between primary and secondary olfactory areas together with the anterior commissure. No significant correlation was found between DTI metrics and sensory or cognition test results.
Conclusions:
We present the first combined fiber dissection analysis and tractography of the olfactory system. We suggest that the primary olfactory network is defined by the olfactory tract/bulb and primary olfactory cortices through the lateral stria only. UF, IFOF and cingulum are the associative pathways supporting the connectivity between primary and secondary olfactory areas together with the Anterior commissure. We suggest to consider these structures as a secondary olfactory network. Further work is needed to attain deeper understanding of pathological and physiological implications of the olfactory system.
Modeling and Analysis Methods:
Connectivity (eg. functional, effective, structural) 2
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
Cortical Anatomy and Brain Mapping 1
Perception, Attention and Motor Behavior:
Chemical Senses: Olfaction, Taste
Keywords:
Cognition
Smell
STRUCTURAL MRI
Sub-Cortical
Tractography
WHITE MATTER IMAGING - DTI, HARDI, DSI, ETC
1|2Indicates the priority used for review
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Please indicate below if your study was a "resting state" or "task-activation” study.
Resting state
Healthy subjects only or patients (note that patient studies may also involve healthy subjects):
Healthy subjects
Was this research conducted in the United States?
No
Were any human subjects research approved by the relevant Institutional Review Board or ethics panel?
NOTE: Any human subjects studies without IRB approval will be automatically rejected.
Yes
Were any animal research approved by the relevant IACUC or other animal research panel?
NOTE: Any animal studies without IACUC approval will be automatically rejected.
Not applicable
Please indicate which methods were used in your research:
Structural MRI
Diffusion MRI
For human MRI, what field strength scanner do you use?
3.0T
Which processing packages did you use for your study?
SPM
Free Surfer
Provide references using APA citation style.
1. Allison AC. The secondary olfactory areas in the human brain. Journal of Anatomy. oktober 1954;88(4):481–8.
2. Kavoi BM, Jameela H. Comparative Morphometry of the Olfactory Bulb, Tract and Stria in the Human, Dog and Goat. International Journal of Morphology. september 2011;29(3):939–46.
3. Latini F, Hjortberg M, Aldskogius H, Ryttlefors M. The use of a cerebral perfusion and immersion-fixation process for subsequent white matter dissection. Journal of Neuroscientific Methods. 30 september 2015;253:161–9.
4. López‐Elizalde R, Campero A, Sánchez‐Delgadillo T, Lemus‐Rodríguez Y, López‐González Mi, Godínez‐Rubí M. Anatomy of the olfactory nerve: A comprehensive review with cadaveric dissection. Clinical Anatomy. January 2018;31(1):109–17.
No