Intra- and interhemispheric white matter tract associations with auditory spatial processing: Distinct normative and...

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Aging Research

Background:

• Auditory spatial processing declines with age, impacting speech perception in noise.
• White matter architecture's role in auditory spatial processing and aging is poorly understood.
• The arcuate fasciculus and corpus callosum are implicated in auditory spatial attention and integration.

Purpose of the Study:

• Investigate the relationship between white matter microstructure and age-related differences in auditory spatial processing.
• Determine if the arcuate fasciculus and corpus callosum mediate age-group differences in identifying spatially cued speech.
• Identify specific white matter tracts crucial for auditory spatial processing.

Main Methods:

• Diffusion imaging to assess white matter microstructure.
• Analysis of fractional anisotropy (FA) in the right arcuate fasciculus and corpus callosum.
• Correlational and mediation analyses linking white matter integrity to speech perception performance.

Main Results:

• Higher fractional anisotropy (FA) in the right arcuate fasciculus and corpus callosum correlated with better speech segregation and identification.
• Individual differences in corpus callosum microstructure mediated age-group differences in auditory spatial processing.
• Callosal tracts connecting pre-frontal and posterior parietal cortices were particularly important.

Conclusions:

• White matter integrity, specifically in the arcuate fasciculus and corpus callosum, is crucial for auditory spatial processing across the lifespan.
• The corpus callosum plays a significant role in mediating age-related declines in auditory spatial abilities.
• Both intrahemispheric and interhemispheric white matter pathways are vital for effective auditory spatial processing.