Rosen, S;
Wise, RJS;
Chadha, S;
Conway, EJ;
Scott, SK;
(2011)
Hemispheric Asymmetries in Speech Perception: Sense, Nonsense and Modulations.
PLOS ONE
, 6
(9)
, Article e24672. 10.1371/journal.pone.0024672.
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Abstract
Background: The well-established left hemisphere specialisation for language processing has long been claimed to be based on a low-level auditory specialization for specific acoustic features in speech, particularly regarding 'rapid temporal processing'.Methodology: A novel analysis/synthesis technique was used to construct a variety of sounds based on simple sentences which could be manipulated in spectro-temporal complexity, and whether they were intelligible or not. All sounds consisted of two noise-excited spectral prominences (based on the lower two formants in the original speech) which could be static or varying in frequency and/or amplitude independently. Dynamically varying both acoustic features based on the same sentence led to intelligible speech but when either or both acoustic features were static, the stimuli were not intelligible. Using the frequency dynamics from one sentence with the amplitude dynamics of another led to unintelligible sounds of comparable spectro-temporal complexity to the intelligible ones. Positron emission tomography (PET) was used to compare which brain regions were active when participants listened to the different sounds.Conclusions: Neural activity to spectral and amplitude modulations sufficient to support speech intelligibility (without actually being intelligible) was seen bilaterally, with a right temporal lobe dominance. A left dominant response was seen only to intelligible sounds. It thus appears that the left hemisphere specialisation for speech is based on the linguistic properties of utterances, not on particular acoustic features.
| Type: | Article |
|---|---|
| Title: | Hemispheric Asymmetries in Speech Perception: Sense, Nonsense and Modulations |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1371/journal.pone.0024672 |
| Publisher version: | http://dx.doi.org/10.1371/journal.pone.0024672 |
| Language: | English |
| Additional information: | © 2011 Rosen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. S.K.S. is funded by Grant No. WT074414MA from the Wellcome Trust. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. |
| Keywords: | HUMAN AUDITORY-CORTEX, TEMPORAL ENVELOPE, HUMAN BRAIN, CUES, LATERALIZATION, SENSITIVITY, ACTIVATION, AMPLITUDE, POSITION, FEATURES |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences > Institute of Cognitive Neuroscience UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences > Speech, Hearing and Phonetic Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1326272 |
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