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Updated: May 31, 2026
10:59
New Methods to Study Gustatory Coding
Published on: June 29, 2017
Olfactory bulb-cortex oscillations encode perceived odor intensity rather than concentration
Frans Nordén1, Irene Zanettin1, Mikael Lundqvist1
1Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Plos Biology
|May 29, 2026
Summary
Human olfactory bulb and piriform cortex dynamics encode perceived odor intensity, not concentration. Bidirectional brain communication maintains consistent perception across varying odor levels.
Area of Science:
- Neuroscience
- Sensory Perception
- Olfactory System
Background:
- Perceived stimulus intensity is crucial for sensory experience.
- The neural mechanisms of intensity encoding in the human olfactory system are not well understood.
Purpose of the Study:
- To investigate how the human olfactory system encodes perceived stimulus intensity.
- To elucidate the role of oscillatory dynamics in the olfactory bulb (OB) and piriform cortex (PC) in intensity coding.
Main Methods:
- Utilized noninvasive electrobulbogram recordings.
- Analyzed oscillatory dynamics, including gamma-band and beta-band activity.
- Investigated phase-amplitude coupling and transient beta bursts between OB and PC.
Main Results:
- Oscillatory dynamics in the OB and PC primarily encode perceived intensity, not physical concentration.
- Early gamma-band activity in the OB transmits perceived intensity to the PC.
- Top-down beta-band feedback from the PC modulates OB activity.
Conclusions:
- A novel oscillatory framework underlies intensity coding in the human olfactory system.
- Perception, rather than physical stimulus properties, plays a primary role.
- This mechanism supports predictive processing and perceptual constancy in early sensory circuits.
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