An fMRI study of brain regions activated by auditory attention

Abstract

The purpose of this study was to identify brain regions activated by auditory attention using fMRI (functional magnetic resonance imaging). The activated brain regions, which were identified between "listening" and "hearing," were compared quantitatively. We also compared the activation volume in each region using original software that we developed. Additionally, SPM2 software was employed to analyze the results. The subjects were twelve healthy adults (five men, seven women) without hearing problems. The tasks performed were a monosyllabic hearing test employing both male and female speakers, and the same monosyllabic hearing test under ambient noise. The results showed that the dominant regions activated by auditory attention, for both male and female speakers, were the middle frontal gyrus, orbital cortex, superior temporal cortex, and inferior semilunar lobule. ANOVA results indicated that the frontal area was the most activated region. Analysis according to gender of the speaker and measurement of activation level indicated that activation increases in response to the voice of an opposite gender speaker. Together these results suggest that the prefrontal cortex, supramarginal gyrus, and cingulate gyrus are responsible for auditory attention. Also, the affected brain regions activate more when listening to a speaker of the opposite gender than to a speaker of the same gender.