Lateralization of music processing with noises in the auditory cortex: an fNIRS study

Area of Science:

• Neuroscience
• Auditory Perception
• Cognitive Psychology

Background:

• Hemispheric lateralization is crucial for music processing.
• The impact of background noise on this lateralization is not fully understood.
• Auditory environments can influence brain activity patterns.

Purpose of the Study:

• To investigate how background noise affects hemispheric lateralization during music perception.
• To quantify changes in brain activity using functional near-infrared spectroscopy (fNIRS).
• To explore the relationship between noise intensity and music perception effort.

Main Methods:

• 14 subjects were exposed to four auditory conditions: music only, noise only, music with noise, and music interfered by noise.
• Functional near-infrared spectroscopy (fNIRS) measured hemodynamic responses in both brain hemispheres.
• The difference between mean and minimum hemodynamic response values distinguished stimulus-evoked activity.

Main Results:

• Right-hemispheric lateralization for music processing was approximately 75%.
• Noise-only stimuli showed about 65% lateralization.
• Music mixed with noise increased right-hemispheric lateralization, particularly when noise levels were slightly lower than music.
• Excessive noise reduced subjects' music discernment efforts.

Conclusions:

• Background noise significantly modulates hemispheric lateralization in music processing.
• Increased cognitive effort to perceive music in noisy environments strengthens right-hemispheric dominance.
• Optimal noise levels can enhance music perception, while excessive noise hinders it.