Observation of Neural Processes of Auditory Scene Analysis by Magnetoencephalography

Abstract

In order to elucidate the auditory mechanism of sensory cue grouping and stream formation, we used a 37-channel SQUID magnetoencephalographic system to analyze the magnetic fields elicited by spoken sound stimuli consisting of an isolated word, an isolated consonant (/k/) burst, and a concurrent but perceptually segregated version of them. Only the overlapped /k/ burst among the five measured neural activities had a statistically significant difference in the location of the equivalent single-current dipoles in both hemispheres. The result suggests that the neurons activated by the overlapped /k/ burst are at least partially different from those activated by the other sounds; thereby supporting our new hypothesis that concurrent auditory events are spatially represented within the auditory cortex.

Key Words:

• auditory cortex
• auditory scene analysis
• MEG
• stream segregation
• spatial mapping
• speech sound
• attention.