Healthy, Olfaction
Conditions
Keywords
healthy volunteer, electroencephalography (EEG), magnetic resonance imaging (MRI), odors
Brief summary
This study investigates the causal effects of low-intensity transcranial focused ultrasound (tFUS) on odor valence perception and odor-elicited avoidance behaviors in healthy adults. Participants undergo sham and active tFUS targeting the amygdala (AMYG) and ventral striatal olfactory tubercle (VSOT) in a within-subject, randomized, sham-controlled crossover design. Outcomes include subjective odor ratings and objective neurophysiological and behavioral indices of odor valence processing. This research is exploratory and mechanistic in nature and is not intended to evaluate clinical safety or therapeutic efficacy.
Interventions
non-invasive brain stimulation using tFUS
Sponsors
Medical University of South Carolina
National Institute on Deafness and Other Communication Disorders (NIDCD)
National Institutes of Health (NIH)
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* Age 18-65 years * Healthy adult volunteers * Normal olfactory function (Sniffin' Sticks total TDI ≥ 30.75) * Ability to provide informed consent * English fluency sufficient for task completion
Exclusion criteria
* MRI or tFUS contraindications (e.g., metal implants, claustrophobia, pregnancy) * Sinonasal conditions affecting airflow or smell * Current use of medications that alter olfaction * Positive urine drug screen
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Odor Valence Rating | from the baseline visit until the third follow-up visit (about 1 month) | Participant rating of odor pleasantness on a 0-100 mm visual analog scale (e.g., unpleasant → pleasant) |
| Late Positive Potential | from the baseline visit until the third follow-up visit (about 1 month) | Mean EEG amplitude (400-800 ms) at centro-parietal sites to olfactory-visual stimuli |
| Sniff Volume | from the baseline visit until the third follow-up visit (about 1 month) | Total nasal airflow (in mL) per odor trial, measured via nasal cannula or spirometer |
| Corrugator Supercilii EMG Activity | from the baseline visit until the third follow-up visit (about 1 month) | Mean EMG amplitude from facial muscle sensitive to negative affect and aversion |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Odor Intensity Rating | from the baseline visit until the third follow-up visit (about 1 month) | Participant rating of odor intensity on a 0-100 mm visual analog scale (e.g., not at all → extremely) |
| Odor Avoidance Rating | from the baseline visit until the third follow-up visit (about 1 month) | Participant rating of their desire to avoid the odor on a 0-100 mm visual analog scale (e.g., "not at all" → "extreme") |
| Sniff Rate | from the baseline visit until the third follow-up visit (about 1 month) | Breaths per min or per trial window in response to odor exposure |
Contacts
CONTACTNicole Cash, Study Coordinator
Outcome results
None listed