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Updated: Apr 2, 2026
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A Free-breathing fMRI Method to Study Human Olfactory Function
Published on: July 30, 2017
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Structural connectivity of the human olfactory network and its relation to aging and olfactory function.
Xin Li1,2, Jonas Olofsson3, Jonas Persson1,4
1Aging Research Center, Karolinska Institute and Stockholm University, Stockholm, Sweden.
Imaging Neuroscience (Cambridge, Mass.)
|April 1, 2026
Summary
Older adults
Area of Science:
- Neuroscience
- Aging Research
- Cognitive Science
Background:
- Olfactory dysfunction in older adults is linked to memory decline and Alzheimer's disease (AD).
- The brain's structural basis for olfactory impairment and its connection to memory is poorly understood.
- Existing research often focuses on single brain regions or tracts, not the entire olfactory network.
Purpose of the Study:
- To investigate the structural connectivity of the olfactory network in relation to aging, olfactory function, and cognitive abilities.
- To identify specific white-matter pathways connecting the primary olfactory cortex (POC) to the brain and their functional relevance.
- To explore the neural underpinnings of olfactory and memory function, particularly in the context of aging and AD biomarkers.
Main Methods:
- Reconstruction of the structural olfactory network using white-matter connections from the primary olfactory cortex (POC) to the whole brain.
- Multivariate analyses applied to a population-based sample (n=137) to examine relationships between age, olfactory network connectivity, and cognitive performance.
- Assessment of olfactory function (odor identification, odor threshold) and cognitive functions (episodic memory, processing speed, working memory).
Main Results:
- Older age correlated with reduced connectivity strength between POC subregions and adjacent brain areas, indicating olfactory network reorganization.
- Structural connectivity of the olfactory network was significantly associated with odor identification, episodic memory, and odor threshold performance.
- Specific pathways, including olfactory tubercle (TUB)-caudate and olfactory nucleus (AON)-hippocampus, were crucial for both olfaction and episodic memory.
Conclusions:
- The study reveals distinct structural connectivity profiles for POC subregions and highlights age-related changes in the olfactory network.
- Olfactory network integrity is linked to olfactory and episodic memory functions, suggesting a shared neural foundation.
- Findings provide network-level insights into the common neural basis of olfaction and memory, relevant for early AD detection.
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