Automatic Speech in the Three Structure Model – Part 3. Integration in Neuroscience: A Core Problem – Part 15

reviseddescriptionofspeechinthreestructuremodel

In the previous post, we looked more closely at automatic speech with some video examples. Just returning to one of these examples have a look at the clip below.

In the three structure model, automatic speech represents the final common pathway through which speech is actuated. The final common pathway is the electrical activity occurring in the nerves (mostly cranial nerves) that actuate the muscles of speech. It is assumed that this activity is entirely unconscious and is in no way capable of being conscious activity.

If you watch the clip repeatedly and very carefully it becomes clear that unsurprisingly the tongue plays a central role in speech production. Some of the actions that are seen are

1. Mouth opening

2. Lips pursing to articulate sounds

3. Tongue depressing

4. Tongue moving up to touch hard palate

5. Tongue touching soft palate and closing nasopharyngeal air space

If we assemble some of these actions to reproduce the actions at the beginning of the video it would read something like as follows

1. Open Mouth by lowering jaw

2. Depress tongue

3. Push lips together

4. Lift tongue to touch hard palate

5. Move tongue rapidly down

6. Move tongue to soft palate to close off nasopharynx

Whilst this is going on there are two other things happening

1. The force of air expulsion from the lungs is being controlled by the muscles of respiration

2. The vocal cords are being relaxed and contracted whilst the lung air expulsion is vibrating the vocal cords

The combination of all of this results in speech. From the multiple steps above it seems entirely unlikely that conscious or at least potentially conscious activity (i.e. transient unconscious activity) is not playing a central role in the transition from one step to another of this process.

In other words it is highly unlikely that the brain sends a signal to the muscles associated with speech and then sits passively by while all of the actions above take place. It is most likely that the conscious/transient unconscious activity intervenes in each transition.

So for instance you would be able to speak very slowly. In so doing you would exert a clear and conscious control over actions. You could lower your jaw and be absolutely certain that you are consciously in control of this action. You could purse your lips and be similarly confident that you are in conscious control of this action. You could touch the roof of the mouth with your tongue and again be confident that you are in conscious control of this action. By definition such actions are not absolute unconscious activity but conscious/transient conscious activity.

This means that the place for absolute unconscious activity takes a more peripheral role in speech. It becomes much less relevant and probably applies to the last few milliseconds of the signals moving from primary cortex to effector nerves.

If this is correct it would mean that this is recipricocity between streams of conscious speech commands and brief bursts of ‘reflexive’ automatic speech. This much is clear from the above thought experiment but it is also relevant to some of the theoretical knowledge about corticospinal pathways and also their relation to the Cerebellum which is closely involved in the monitoring of motor activities.

Appendix – Related Resources on the TAWOP Site

In Support of Method

A Review of the Structure of Scientific Revolutions

An Interpretation of Scientific Revolutions

Integration in Neuroscience: A Core Problem – Part 1

Integration in Neuroscience: A Core Problem – Part 2

Integration in Neuroscience:A Core Problem – Part 3

Integration in Neuroscience: A Core Problem – Part 4: A Language for Mind and Brain?

Integration in Neuroscience: A Core Problem – Part 5: A Three Structure Model

Integration in Neuroscience: A Core Problem – Part 6: Reflection on the Three Structure Model

Integration in Neuroscience: A Core Problem – Part 7: The Unconscious in the Three Structure Model

Integration in Neuroscience: A Core Problem – Part 8

Integration in Neuroscience: A Core Problem – Part 9

Integration in Neuroscience: A Core Problem – Part 10

Integration in Neuroscience: A Core Problem – Part 11

Integration in Neuroscience: A Core Problem – Part 12

Index: There are indices for the TAWOP site here and here Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link. Podcast: You can listen to this post on Odiogo by clicking on this link (there may be a small delay between publishing of the blog article and the availability of the podcast). It is available for a limited period. TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link. Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk. Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

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