Next Friday, October 18 at 2:15 p.m. (CET) we see the premiere of the Lund PPP (Phonetics, Phonology, Prosody) meetings. We have Professor Alan Wrench (Queen Margaret University, Articulate Instruments Ltd) with us online via zoom. He will give a talk on the topic A Pulse-Step Equilibrium Model of Motor Control (see below), and afterwards there will be a workshop where we will discuss the Sosnik et al. (2004) paper.

A Pulse-Step Equilibrium Model of Motor Control
Alan Wrench
Queen Margaret University, Articulate Instruments Ltd

This presentation will introduce an evolving novel theory, initiated 10 years ago, that describes how movements could be generated and controlled, and which, if correct, has implications for how we view the process of speech production including unit selection, rhythm, coarticulation, and prominence. A pulse-step model of motor control is introduced that fits with observed neural signals, laws of movement and kinematics and is achievable efficiently with known neural circuitry. The talk will start with an introduction to some of these circuits and signals and the concept of neuromuscular compartments. Then we will demonstrate with a simple biomechanical model of a 2-joint upper limb how the proposed pulse step model produces observed limb trajectories, velocity profiles and EMG muscle signals. A further biomechanical demonstration explains how efficient sequences of movements may be learnt, by simulating observations by Sosnik (2004). In the second part of the talk there will be an analysis of lingual articulation that exemplifies how speech motor control may function by selecting either discrete articulator movements or more efficient learnt movement sequences. Evidence, based on ultrasound tongue contour analysis, indicates that prosodic prominence may be simply effected by sustaining a motor command or slowing a transition velocity and that efficient sequences are used where appropriate. We also demonstrate that these units of movement may be initiated in accordance with a neural timekeeper, a divide-down clock that for speech, operates at 27ms intervals and multiples thereof.

Sosnik, R., Hauptmann, B., Karni, A., & Flash, T. (2004). When practice leads to co-articulation: the evolution of geometrically defined movement primitives. Experimental Brain Research, 156, 422-438. https://doi.org/10.1007/s00221-003-1799-4 

About the Lund PPP-meetings
Anyone with the slightest interest in phonetics, phonology and prosody, and what actually unites these three (!) is most welcome to participate. The Lund PPP-meetings are hybrid meetings with invited guests giving a talk, followed by a workshop where we discuss a paper.