Rescuing Visual Perception in Aging Adults by Restructuring the Alpha-Gamma Neural Code
Boston University Charles River Campus
Summary
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.
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 oscill…
Eligibility
- Age range
- 18+ years
- Sex
- All
- Healthy volunteers
- Yes
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, macul…
Interventions
- DeviceHigh 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.
Location
- 111 Cummington Mall, Boston UniversityBoston, Massachusetts