Altered pattern evoked retinal and cortical potentials associated with human senescence.

Area of Science:

• Neuroscience
• Ophthalmology
• Gerontology

Background:

• Healthy elderly individuals often experience visual deficits due to aging.
• Age-related changes in ocular media and visual pathway neurophysiology contribute to these deficits.
• While optical changes are known, age-dependent variations in visual neurophysiology remain unclear.

Purpose of the Study:

• To investigate age-related alterations in pattern-specific biopotentials from the human retina and visual cortex.
• To compare neurophysiological responses between young and elderly individuals using visual evoked potentials.

Main Methods:

• Simultaneously monitored pattern-reversal visual evoked potentials (PRVEPs) using counterphasing patterns at different rates and sizes.
• Studied young (20-30 years) and healthy elderly (70-80 years) observers with good visual acuity (≥20/30).
• Corrected data for senile miosis effects on retinal illumination.

Main Results:

• Elderly individuals showed significant variations in biopotential waveform characteristics.
• Pattern-reversal retinal potentials (PRRP) amplitude was uniformly reduced in the elderly.
• Pattern-reversal visual evoked potentials (PRVEP) amplitude reductions were also observed, varying with stimulus conditions; no significant latency changes were found.

Conclusions:

• Normal aging is associated with alterations in the physiological properties of neural elements in both the retina and visual cortex.
• Reduced neural signal amplitude, rather than delayed processing, characterizes age-related visual pathway changes.