Aging patterns of Japanese auditory semantic processing: an fMRI study

Area of Science:

• Neuroscience
• Cognitive Psychology
• Gerontology

Background:

• Listening comprehension is often assumed to decline with age, contrary to stereotypes of universal cognitive deterioration.
• Investigating the neural mechanisms supporting preserved auditory semantic function in older adults is crucial.

Purpose of the Study:

• To examine how neural mechanisms support auditory semantic processing in older adults.
• To compare brain activity and connectivity in younger and older adults during a semantic task.

Main Methods:

• Functional magnetic resonance imaging (fMRI) using a 3 Tesla MRI scanner.
• Auditory semantic-tone task administered to 22 younger and 21 older Japanese adults.
• Analysis of brain activation, laterality, and interregional connectivity.

Main Results:

• Older adults exhibited preserved accuracy but slower responses compared to younger adults.
• Weakened interregional connectivity and largely unchanged activation/laterality were observed in older adults.
• Superiorly performing older adults showed increased left-lateralization and stronger connectivity within domain-general networks.

Conclusions:

• Auditory semantic processing appears relatively preserved in aging, challenging notions of inevitable cognitive decline.
• Cortical reorganization, including increased left-lateralization and connectivity, may underlie preserved function in older adults.
• Observed neural changes align with neurocognitive aging models, suggesting their applicability to age-intact cognitive functions.