Maegherman, Gwijde Gerfen Lidewij;
(2020)
The cognitive and neural mechanisms involved in motor imagery of speech.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Inner speech is a common phenomenon that influences motivation, problem-solving and self-awareness. Motor imagery of speech refers to the simulation of speech that gives rise to the experience of inner speech. Substantial evidence exists that several cortical areas are recruited in general motor imagery processes, including visual and speech motor imagery, but the evidence for primary motor cortex involvement is less clear. One influential model proposes that motor cortex is recruited during speech motor imagery, while another prominent model suggests motor cortex is bypassed. This thesis presents six experiments that explore the role of motor cortex in speech motor imagery. Experiments 1-3 build on established visual motor imagery tasks and expand these tasks to the speech motor imagery domain for the first time, using behavioural (experiments 1 and 2) and neuroimaging methods (experiment 3). Experiment 4 uses transcranial magnetic stimulation to explore motor cortex recruitment during a speech imagery condition, relative to a motor execution and baseline condition in hand and lip muscles. Experiments 5 and 6 use transcranial magnetic stimulation to explore speech motor imagery in tongue muscles relative to a hearing and a baseline condition. The results show that recruitment of motor cortex during speech motor imagery is modulated depending on task demands: simple speech stimuli do not recruit motor cortex, while complex speech stimuli are more likely to do so. The results have consequences specifically for models that always or never implicate motor cortex: it appears that complex stimuli require more active simulation than simple stimuli. In turn, the results suggest that complex inner speech experiences are linked to motor cortex recruitment. These findings have important ramifications for atypical populations whose inner speech experience may be impaired, such as those who experience auditory verbal hallucinations, or those with autism spectrum disorder.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | The cognitive and neural mechanisms involved in motor imagery of speech |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices 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 |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10116884 |
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