Effect of age on lateralized auditory processing

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Aging Research

Background:

• Auditory processing lateralization varies with stimuli and tasks.
• Aging diminishes anatomical connectivity, impacting hemispheric interaction in the auditory cortex.
• Efficient hemispheric interaction is crucial for processing complex auditory stimuli.

Purpose of the Study:

• To investigate the effects of aging on auditory cortex processing lateralization and hemispheric interaction.
• To compare brain activity during auditory tasks with differing demands on hemispheric interaction in younger and older adults.

Main Methods:

• Magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) were used.
• Two tasks were employed: tone categorization (right-dominant) and sequential comparison (bilateral).
• The contralateral noise procedure was utilized to assess auditory processing.

Main Results:

• Older adults showed increased auditory cortex recruitment, particularly during the comparison task requiring greater hemispheric interaction.
• Functional connectivity from the auditory cortex was stronger in older adults during the comparison task.
• DTI revealed reduced fractional anisotropy and increased mean diffusivity in the corpus callosum of older adults, indicating decreased interhemispheric connections.

Conclusions:

• Reduced anatomical interhemispheric connections in aging necessitate greater neural resources for tasks demanding functional hemispheric interaction.
• Older adults compensate for diminished connectivity by increasing auditory cortex recruitment and functional connectivity.