Magnetic resonance imaging methods recently demonstrated regional
cerebral signal changes in response to limb movement and visual
stimulation, attributed to blood flow enhancement. We studied 5 normal
subjects scanned while listening to auditory stimuli including
nonspeech noise, meaningless speech sounds, single words, and
narrative text. Imaged regions included the lateral aspects of both
hemispheres. Signal changes in the superior temporal gyrus and
superior temporal sulcus were observed bilaterally in all
subjects. Speech stimuli were associated with significantly more
widespread signal changes than was the noise stimulus, while no
consistent differences were observed between responses to different
speech stimuli. Considerable intersubject variability in the
topography of signal changes was observed. These observations confirm
the utility of magnetic resonance imaging in the study of human brain
structure-function relationships and emphasize the role of the
superior temporal gyrus in perception of acoustic-phonetic features of
speech, rather than processing of semantic features.