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Recruiting NCT07208318

Restructuring the Alpha-Gamma Code in Aging Vision

Early Phase I Interventional Aging Visual Perception Noninvasive Brain Stimulation

For patients and families

In plain language

An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.

What is being studied
The protocol lists: High definition transcranial electrical current stimulation.
Who it may be relevant to
Registry conditions: Aging, Visual Perception, Noninvasive Brain Stimulation. Basic parameters: from 18 years · All.
What needs checking
Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
Where it takes place
United States
Next step
Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →

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Official title

Rescuing Visual Perception in Aging Adults by Restructuring the Alpha-Gamma Neural Code

Overview

Tests whether age-related visual deficits arise from disrupted alpha-gamma coupling in visual cortex (V1) and MT. Uses fMRI, source-resolved HD-EEG, and personalized complex-waveform HD-tACS to (1) quantify aging effects on phase-amplitude coupling, (2) drive PAC into a preferred "gamma-at-alpha-troughs" state, and (3) bidirectionally change perception by aligning gamma to alpha troughs vs peaks. Two five-day, double-blind, sham-controlled studies (n=120 each) target contrast sensitivity (V1) and 3D shape-from-motion (MT), aiming for mechanistic insight and remediation in older adults with implications for ADRD.

Detailed description

The project probes a causal account of age-related perceptual decline by focusing on alpha-gamma phase-amplitude coupling (PAC) in early visual cortex and area MT. The central hypothesis is that aging alters both the magnitude and phase structure of alpha-gamma interactions, degrading visual performance; restoring a preferred configuration-gamma power nested at alpha troughs-should improve perception.

Multimodal methods combine structural/functional MRI, high-density EEG with source reconstruction, and individualized complex-waveform HD-tACS tuned to each participant's neuroanatomy and oscillatory frequencies. Three questions drive the work: (i) Do age-related deficits track changes in alpha-gamma PAC magnitude/phase? (ii) Can frequency-coupled HD-tACS enforce the preferred PAC configuration and enhance perception, especially in more impaired older adults? (iii) Is perception bidirectionally controllable by placing gamma at alpha troughs (facilitation) versus peaks (disruption)?

Two specific aims implement matched, five-day, within-subjects, double-blind, sham-controlled experiments with 120 participants each. Aim 1 targets early visual cortex to test whether contrast sensitivity deficits scale with age, spatial frequency, and noise, and whether personalized HD-tACS can optimize PAC to improve contrast perception. Aim 2 targets MT to test whether 3D shape-from-motion (parallax) judgments decline with age as a function of surface-point lifetime and simulated depth, and whether trough- versus peak-aligned stimulation can restructure PAC to enhance motion-based shape perception. Outcomes will establish mechanistic links between PAC and visual aging and evaluate a noninvasive, personalized intervention path relevant to age-related decline and ADRD.

Interventions

  • Device High definition transcranial electrical current stimulation
    Low-intensity and safe, noninvasive application of electrical current to the human scalp with the goal of gradually modulating levels of neuronal excitability.

Primary outcome measures

  • contrast sensitivity [Time frame: Baseline (pre-stimulation) and immediately post-stimulation, collected on each of the 5 study days.]
  • 3D structural-from-motion [Time frame: Baseline (pre-stimulation) and immediately post-stimulation, collected on each of the 5 study days.]
  • phase-amplitude coupling [Time frame: Baseline (pre-stimulation) and immediately post-stimulation, collected on each of the 5 study days.]

Eligibility criteria

Inclusion criteria

  • 18+ years of age or older
  • normal or corrected-to-normal visual acuity, color vision, and stereo vision

Exclusion criteria

  • not pregnant,
  • no metal implants in head,
  • no implanted electronic devices,
  • no history of neurological problems or head injury,
  • no skin sensitivity,
  • no claustrophobia,
  • no dementia (normal Mini Mental State Examination between 24-30; Montreal Cognitive Assessment > 25)
  • no depression (normal Beck Depression Inventory II <13; Geriatric Depression Scale < 10)
  • no ophthalmological diseases (e.g., strabismus, glaucoma, cataract, macular degeneration)
  • no history of psychosis
  • no cognitive deficits (MMSE score>24; MoCA>25)
  • cannot be taking any psychoactive medication.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation
Randomized
Model
Crossover
Masking
Double blind
Primary purpose
Basic science

Study locations

United States · 1 center
  • 111 Cummington Mall, Boston University — Boston

Identifiers

NCT: NCT07208318 · 4230E_2

Primary sources (government registries)

View this study on ClinicalTrials.gov ↗