Lateralized enhancement of auditory cortex activity and increased sensitivity to self-generated sounds

Area of Science:

• Neuroscience
• Auditory Perception
• Motor Control

Background:

• Voluntary actions with auditory feedback modulate auditory cortex responses.
• This modulation is hypothesized to involve corollary discharge from motor cortex.
• The precise relationship between effector, modulation type, and perceptual changes remains unclear.

Purpose of the Study:

• To investigate the neural and behavioral effects of self-generated sounds versus externally generated sounds.
• To explore the lateralization of auditory cortex enhancement based on effector hand.
• To elucidate the role of corollary discharge in auditory perception.

Main Methods:

• Functional magnetic resonance imaging (fMRI) in healthy subjects.
• Behavioral assessment of auditory thresholds.
• Functional connectivity analysis.

Main Results:

• Bilateral enhancement in auditory cortex for self-generated sounds compared to external sounds.
• Stronger auditory enhancement when the sound-producing hand was contralateral to the auditory cortex.
• Lowered binaural hearing thresholds for self-generated sounds and lowered monaural thresholds for sounds produced by the ipsilateral hand.

Conclusions:

• A corollary discharge from active motor cortex enhances auditory cortex activity.
• This motor-to-auditory pathway increases perceptual sensitivity in a lateralized manner.
• Findings clarify the link between action, auditory processing, and sensory perception.