将呼吸同步嗅觉计与大脑模拟相结合，研究气味对皮质脊髓兴奋性和有效连接性的影响

Overview

This study presents a novel experimental method using a breath-synchronized olfactometer combined with transcranial magnetic stimulation (TMS) to probe the interactions between olfactory perception and motor system responses. The research focuses on how pleasant and unpleasant odors modulate corticospinal excitability and effective connectivity, which could inform clinical investigations into olfactory-motor interactions.

Key Study Components

Area of Science

• Neuroscience
• Olfactory processing
• Transcranial magnetic stimulation

Background

• The interplay between olfactory stimuli and motor system responses is underexplored.
• Understanding how odors affect motor excitability has implications for clinical conditions.
• Synchronization of olfactory and TMS delivery is critical for accurate measurements.
• This approach is particularly relevant for studying psychiatric disorders that alter odor perception.

Purpose of Study

• To investigate how pleasant and unpleasant odors influence corticospinal excitability.
• To examine effective connectivity changes in normal and pathological conditions.
• To develop a rigorous method for studying olfactory-motor interactions.

Methods Used

• Utilized a breath-synchronized olfactometer alongside dual-coil TMS.
• Engaged healthy participants to assess motor responses during odor presentation.
• Synchronizing olfactory conditions with human nasal breathing was critical.
• Electromyography (EMG) was recorded to evaluate motor evoked potentials (MEPs).
• Stimuli included pleasant, unpleasant, and neutral odors presented randomly.

Main Results

• MEPs were influenced by the hedonic value of the odorants, showing varying peak amplitudes.
• Results indicated a suppressive effect of the left dorsolateral prefrontal cortex (DLPFC) on the primary motor cortex (M1).
• Key comparisons revealed the modulatory role of olfactory stimuli on motor excitability.
• Synchronizing stimuli aligned with breath phases improved experimental validity.

Conclusions

• This study enables precise investigation of olfactory-motor system interactions and the impact of odor valence.
• The novel methodology may enhance understanding of olfactory-related disorders.
• Findings have potential implications for therapeutic approaches in psychiatric contexts.

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