Cerebral Cortex Advance Access originally published online on June 24, 2007
Cerebral Cortex 2008 18(3):541-552; doi:10.1093/cercor/bhm083
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Processing Prosodic Boundaries in Natural and Hummed Speech: An fMRI Study
1 Clinical Department of Neurology, Innsbruck Medical University, 6020 Innsbruck, Austria, 2 Department of Neuropsychology, Max Planck Institute of Human Cognitive and Brain Sciences, Leipzig, Germany, 3 School of Neurology, Neurobiology, and Psychiatry, Newcastle University Medical School, Newcastle upon Tyne, UK
Address correspondence to email: anja.ischebeck{at}uklibk.ac.at.
Speech contains prosodic cues such as pauses between different phrases of a sentence. These intonational phrase boundaries (IPBs) elicit a specific component in event-related brain potential studies, the so-called closure positive shift. The aim of the present functional magnetic resonance imaging study is to identify the neural correlates of this prosody-related component in sentences containing segmental and prosodic information (natural speech) and hummed sentences only containing prosodic information. Sentences with 2 IPBs both in normal and hummed speech activated the middle superior temporal gyrus, the rolandic operculum, and the gyrus of Heschl more strongly than sentences with 1 IPB. The results from a region of interest analysis of auditory cortex and auditory association areas suggest that the posterior rolandic operculum, in particular, supports the processing of prosodic information. A comparison of natural speech and hummed sentences revealed a number of left-hemispheric areas within the temporal lobe as well as in the frontal and parietal lobe that were activated more strongly for natural speech than for hummed sentences. These areas constitute the neural network for the processing of natural speech. The finding that no area was activated more strongly for hummed sentences compared with natural speech suggests that prosody is an integrated part of natural speech.
Key Words: prosody processing auditory cortex intonational phrase boundaries fMRI sentence processing