Neurovascular coupling in normal aging: a combined optical, ERP and fMRI study

Area of Science:

• Neuroscience
• Aging Research
• Cardiorespiratory Fitness

Background:

• Brain aging involves alterations in hemodynamic and neuronal activity.
• Cardiorespiratory fitness may modulate age-related brain changes.
• Understanding neurovascular coupling is crucial for interpreting brain function studies.

Purpose of the Study:

• To investigate the relationship between neuronal and hemodynamic brain responses in younger and older adults.
• To examine the influence of physical fitness on neurovascular coupling during aging.
• To compare different functional brain measures of neuronal and hemodynamic activity.

Main Methods:

• Visual stimulation (checkerboard reversals) used to elicit brain activity.
• Four measures assessed brain activity in BA17: event-related optical signal (EROS), C1 ERP response, functional magnetic resonance imaging (fMRI), and near-infrared spectroscopy (NIRS).
• Participants included younger adults and older adults with varying physical fitness levels.

Main Results:

• A quadratic relationship between neuronal and hemodynamic effects was observed in both age groups.
• Older adults showed reduced brain activation compared to younger adults.
• Neurovascular coupling functions were similar between age groups using fMRI and deoxy-hemoglobin, but decreased with age and increased with fitness for oxy- and deoxy-hemoglobin coupling.

Conclusions:

• Departures from linearity in neurovascular coupling may occur when using hemodynamic measures.
• Physical fitness plays a role in modulating age-related changes in neurovascular coupling.
• Findings highlight the complex interplay between aging, fitness, and brain function.