In a new JNeurosci paper, Masako Okamoto and colleagues, from the University of Tokyo, explored the brain activity involved in smelling odors.
The researchers recorded brain activity as study volunteers inhaled a panel of odors. The volunteers also completed questionnaires as well as tests for odor detection, identification, and discrimination. A distinct frequency of brain activity arising soon after odor presentation was linked to detecting odors. Notably, the quality of this activity was associated with the ability to discriminate between odors with high accuracy. Another frequency of activity was linked with scent pleasantness, and this activity didn't occur until later. Based on questionnaire answers, the fidelity of this activity was associated with a greater awareness of odor pleasantness in daily life.
Summing up their research, says Okamoto, "In the very early stage after odor onset, the brain primarily encodes objective molecular features of odors to support odor discrimination at the behavioral level, and only later does it begin to represent subjective perceptual attributes, such as pleasantness." The researchers suggest that the different kinds of brain activity they identified may serve as a way to assess olfactory disorders or inform new strategies for enhancing olfactory function.
