Asymmetric, dynamic adaptation in prefrontal cortex during dichotic listening tasks

Area of Science:

• Neuroscience
• Cognitive Science
• Speech Processing

Background:

• Speech processing tasks assess brain health, but neural underpinnings are unclear.
• Previous studies show inconsistent results regarding prefrontal cortex hemispheric asymmetry during dichotic listening.

Purpose of the Study:

• To investigate hemispheric asymmetry in the prefrontal cortex during dichotic listening tasks.
• To gain a deeper understanding of the neural substrates of speech processing.

Main Methods:

• Utilized diffuse correlation spectroscopy (DCS) to monitor cerebral blood flow (CBF) non-invasively.
• Measured CBF in the dorsolateral prefrontal cortex during dichotic listening in human subjects.
• Avoided central confounds present in prior research.

Main Results:

• Dichotic listening tasks induced significant hemispheric asymmetries in both amplitude and kinetics of CBF.
• The left hemisphere showed an accommodative reduction in response amplitude upon repetition of listening tasks, unlike the right hemisphere.
• Demonstrated novel trends in functional asymmetry during speech processing.

Conclusions:

• The findings present a more nuanced view of prefrontal cortex functional asymmetry during auditory tasks.
• Represents the first direct measurements of CBF during an American Speech-Language-Hearing Association-recommended speech processing task.
• Offers potential for improved diagnosis of auditory processing disorders.