Modulation of Higher-Order Olfaction Components on Executive Functions in Humans
Ana B Fagundo1, Susana Jiménez-Murcia2, Cristina Giner-Bartolomé1
1Department of Psychiatry, University Hospital of Bellvitge-IDIBELL, Barcelona, Spain; CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Madrid, Spain.
Plos One
|June 18, 2015
Summary
Reduced sense of smell (hyposmia) is linked to poorer executive functions, including decision-making and cognitive flexibility. Olfactory identification also correlates with cognitive inhibition, suggesting shared neural pathways in the brain.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Olfactory Research
Background:
- The prefrontal cortex (PFC) and orbitofrontal cortex (OFC) are implicated in executive functions and olfaction.
- Limited research exists on the relationship between human olfactory processing and executive functions.
Purpose of the Study:
- To investigate the impact of olfaction on executive functioning.
- To differentiate the roles of primary and cognitive aspects of olfaction in executive tasks.
Main Methods:
- Utilized the Iowa Gambling Task (IGT) for hot executive functions and the Stroop Colour and Word Test (SCWT) and Wisconsin Card Sorting Test (WCST) for cold executive functions.
- Assessed 62 healthy female participants (aged 18-60) with either normosmia (normal smell) or hyposmia (reduced smell) using the 'Sniffin' Sticks' test.
- Measured olfactory threshold, odour discrimination, and odour identification.
Main Results:
- Participants with hyposmia performed significantly worse on decision-making (IGT) and cognitive flexibility (WCST) compared to normosmic individuals.
- Odour identification positively correlated with cognitive inhibition (SCWT-interference).
- Odour discrimination did not predict executive performance.
Conclusions:
- Both hot and cold executive functions are associated with higher-order olfactory abilities in humans.
- Findings support a common neural substrate for olfaction and executive functions in the PFC and OFC.
- Olfaction may serve as a valuable cognitive marker for psychiatric and neurological disorders.
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