Brain signals that reveal how people identify different smells

Electrophysiological Representations of Odor in the Human Brain Study 2

Not applicable Interventional Northwestern University · NCT07386236

This research will test whether brain signals recorded from people having epilepsy surgery show patterns that match how they perceive different smells.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment28 (estimated)
Ages12 Years to 65 Years
SexAll
SponsorNorthwestern University Academic / other
Locations1 site (Chicago, Illinois)
Trial IDNCT07386236 on ClinicalTrials.gov

What this trial studies

The study records direct neural activity from people undergoing intracranial epilepsy surgery while they smell and name odors, linking brain signals to perceptual reports. In Experiment 1A participants freely name odors to capture natural perception while neural responses are recorded, and in Experiment 1B researchers use odor metamers to manipulate perceptual similarity and collect trial-by-trial ratings and neural data. Analyses focus on whether similarity in neural features, including early high-frequency responses in piriform cortex, corresponds to perceptual similarity and odor identity. The approach aims to separate chemical stimulus properties from perceptual identity using human behavioral ratings combined with direct brain recordings.

Who should consider this trial

Good fit: Ideal participants are English-speaking people aged 12–65 who are already scheduled for intracranial brain surgery for medically intractable epilepsy and have no history of smell or taste problems.

Not a fit: People who are not undergoing intracranial surgery, who have existing smell or taste dysfunction, or who fall outside the 12–65 age range would not be eligible and are unlikely to receive direct benefit from participation.

Why it matters

Potential benefit: If successful, the results could clarify how human brains encode odor identity and inform future diagnostic or therapeutic approaches for smell disorders.

How similar studies have performed: Related animal and preliminary human intracranial work suggests early high-frequency piriform responses can carry odor information, so this protocol builds on promising but still limited human evidence.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Ages 12 to 65, english speaker, patients undergoing brain surgery for treatment of medically intractable epilepsy

Exclusion Criteria:

* screening for history of smell or taste problems

Where this trial is running

Chicago, Illinois

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Odor Identity Ratings
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.