Recruiting

Light-Driven Analgesia

Sponsor:

University of North Carolina, Chapel Hill

Code:

NCT07245303

Conditions

Musculoskeletal Pain

Fibromyalgia

Healthy Controls Group - Age and Sex-matched

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Accepted

Interventions

S-cone modulating visual stimulus

Equal Energy White Visual Stimulus

Green light visual stimulus (S-OFF)

Evoked Pressure Pain Stimulus

Study Details

Brief summary:

The goal of this study will be to understand the biological mechanisms that are responsible to light-driven analgesia. Light presented to the retina has been shown to have pain relieving properties in pre-clinical and clinical studies. In this study the investigators will evaluate the functional connectivity between subcortical visual areas and non-image forming brain areas that are involved in pain sensation. The investigators will also evaluate how three colored light stimuli presented to the retina results in changes in whole brain evoked activation patterns in participants with chronic musculoskeletal pain and in healthy controls. The investigators will also assess while brain evoked activation patterns in response to a pressure pain stimulus in the presence of three light stimuli in individuals with chronic musculoskeletal pain and healthy controls.

Conditions

Musculoskeletal Pain

Fibromyalgia

Healthy Controls Group - Age and Sex-matched

Study ID

NCT07245303

Start date

Feb 24, 2026

Status verified date

May, 2026

Completion date

Jan 31, 2030

Anticipated

Primary completion date

Jan 31, 2030

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Accepted

Inclusion Criteria for participants with cMSP and healthy controls (n=30)

  • Adults ≥18 years of age.
  • Individuals who do not have any plans for medication or treatment changes for the next 3 months.
  • Participants must be willing and able to undergo an MRI.
  • Participants must not be claustrophobic
  • Participants must be alert and oriented and able to provide informed consent.
  • Individuals must be able to speak and read English.

Inclusion Criteria for participants with cMSP only (n=30)

  • To be eligible, participants must have a score of ≥7 on the Widespread pain index (WPI) and ≥5 on the symptom severity scale (SSS), or 4-6 on the WPI and ≥9 on the SSS in the 2016 Fibromyalgia Questionnaire.
  • Pain symptoms must have been present for 3 months or longer.
  • Pain must be present in 4 out of 5 body regions.
  • Individuals enrolled will have an average pain severity ≥4 on the 0-10 NRS over the month prior to enrollment to recruit individuals with moderate to severe chronic MSP.

Inclusion Criteria for Participants with Congenital Stationary Night Blindness (n=2)

-2 additional participants without chronic MSP will be recruited with diagnosed congenital stationary night blindness

Exclusion Criteria:

  • Presence of retinal vision disorders or conditions resulting in vision impairment.
  • Patient-reported photosensitivity, photophobia, or aversion (as may occur in autoimmune diseases such as systematic lupus erythematosus).
  • Disorders including uveitis, cataracts, color-blindness, history of seizure disorder.
  • Plans for analgesic treatment plan changes in next 3 months (surgery, analgesic medication changes, injections, pain procedures, etc).
  • Prisoner Status.
  • Pregnancy.
  • Contraindications to MRI imaging. These include the presence of implanted/embedded ferromagnetic materials, implanted medical devices that are not MRI compatible, and claustrophobia.

Study Design

Enrollment

60 participants

Anticipated

Intervention Model

Single group

Primary purpose

Other

Interventions and Outcome Measures

Arms

experimental: Light sequence during imaging

The sequence of stimulus presentation for resting state scans will be Equal Energy White (with luminance modulation) for 8 minutes then Static Green for 8 minutes, followed by an anatomical scan, then S-cone modulating stimuli for 8 minutes.

Interventions

S-cone modulating visual stimulus

The investigators will deliver a uniform wide-field, S-cone modulating stimulus via a fiberoptic, MRI-safe visual stimulator. This stimulus approximates the appearance of white but modulates the S-cone, driving the S-ON and S-OFF pathways by alternating two lights at 19 Hz using a mixture of light emitting diodes (LEDs), including those embedded in our stimulus with spectral peaks of 405, 565, and 660 nm. This stimulus will differentially activate the S-cones where, between the two phases the ratio of S-cone activity is 100. The frequency alternating between the two lights, 19 Hz, was chosen because retinal ganglion cells in the retina still respond robustly but above the cortical perceptual flicker detection threshold.

Equal Energy White Visual Stimulus

The investigators will deliver a uniform wide-field, equal-energy light stimulus via a fiberoptic, MRI-safe visual stimulator. This will serve as a reference condition in which chromatic opponency has been eliminated. This stimulus ensures that the quantal catch of each cone photoreceptor (S-, M- and L-) is held constant using a mixture of LEDs, including those embedded in our stimulus with spectral peaks of 405, 565, and 660 nm. The stimulus will modulate to nearly approximate the appearance of the S-cone modulating light.

Green light visual stimulus (S-OFF)

The investigators will deliver a uniform wide-field, green light modulating stimulus via a fiberoptic, MRI-safe visual stimulator. Static Green (565 nm) Light presented via MRI compatible light guides.

Evoked Pressure Pain Stimulus

The pressure in which a rapid inflation cuff positioned over the left gastrocnemius achieves a pain severity of 40 where 0 is "no pain" and 100 is the "worst pain imaginable will be determined pre-scan and applied during the entire functional imaging acquisition to evoke a deep pressure pain.

Primary outcome measure

  • Resting State Functional Connectivity-seed Voxel Analysis in Participants with cMSP and Healthy Controls [ Time Frame: During 8 minute resting state scan as part of the ~1 hour scanning session ]
  • Whole Brain Evoked Activation Patterns in Response to Chromatic Stimuli Contrasted with Achromatic Stimuli in Participants with cMSP and Healthy Controls [ Time Frame: During 6 minute functional imaging scan within the ~1 hour scanning protocol ]
  • Whole Brain Evoked Activation Patterns in Response to Chromatic Stimuli Contrasted with Achromatic Stimuli in Patients with cMSP and Healthy Controls Exposed to a Pressure Pain Stimulus [ Time Frame: During 6 minute functional imaging scan within the 1 hour scanning protocol ]

Central Contacts and Locations

Central contacts

Matthew Mauck, MD, PhD

919-966-5136matt_mauck@med.unc.edu

Locations

University of North Carolina at Chapel Hill

Recruiting

Chapel Hill, North Carolina, United States, 27599

Contacts

Matthew Mauck, MD, PhD

919-966-5136matt_mauck@med.unc.edu

Principal Investigator:

Matthew Mauck, MD, PhD

More Information

Sponsor

University of North Carolina, Chapel Hill

Last update posted

May 13, 2026

Last verified

May, 2026

Keywords

  • functional connectivity
  • colored light analgesia
  • functional magnetic resonance imaging
  • quantitative sensory testing

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of North Carolina, Chapel Hill on 2026-05-13.