Effect of normal aging upon interhemispheric EEG coherence: analysis during rest and photic stimulation

Area of Science:

• Neuroscience
• Cognitive Aging Research
• Electroencephalography (EEG) Studies

Background:

• Interhemispheric functional connectivity is crucial for cognitive processes.
• Aging is associated with alterations in brain structure and function.
• Electroencephalography (EEG) measures brain electrical activity and connectivity.

Purpose of the Study:

• To compare interhemispheric EEG coherence between younger and elderly adults.
• To investigate resting-state EEG coherence and responses to photic stimulation (PS).
• To examine age-related differences in EEG coherence reactivity.

Main Methods:

• EEG coherence was recorded in 30 younger and 25 elderly adults.
• Measurements were taken at rest and during photic stimulation (5, 10, 15 Hz).
• Coherence changes from rest to stimulation (coherence reactivity) were analyzed.

Main Results:

• Elderly subjects showed significantly lower resting EEG coherence across delta, theta, alpha-3, beta-1, and beta-2 bands.
• During 15 Hz photic stimulation, elderly subjects exhibited significantly higher EEG coherence.
• Elderly participants demonstrated significantly higher coherence reactivity to 15 Hz PS.

Conclusions:

• Elderly individuals display reduced interhemispheric functional connectivity at rest.
• Photic stimulation, particularly at 15 Hz, can enhance brain connectivity in older adults.
• These findings highlight age-dependent modulation of brain connectivity by external stimuli.