[P1] Poster: Day 1

[P1-18] Modelling timing processes in motor imagery

*Ladislas Nalborczyk¹, Camille Grasso² (1. Aix Marseille Univ, CNRS, LPL (France), 2. Cognitive Neuroimaging Unit, CEA DRF/I2BM, INSERM, Université Paris-Sud, Université Paris-Saclay, NeuroSpin Center, Gif/Yvette (France))

Keywords:

motor imagery,scalar property,algorithmic modelling

Behavioural, electrophysiological, and neuroimaging evidence suggests that the motor system is involved in simulating execution during motor imagery. Perhaps not surprisingly then, mental chronometry data revealed that the timing of imagined actions follows the timing of executed actions. However, the timing of imagined actions also conforms to timing laws such as the central tendency effect or the scalar property, according to which the (trial-to-trial) variability of imagined movement times grows linearly with the average movement times. What could account for both the motor and timing properties of imagined actions? We recently developed an algorithmic model of motor imagery, which provides a simplified overarching description of the involvement of the motor system over time during motor imagery and predicts the onset and duration of imagined actions. We previously showed that this model provides an excellent fit to extant data and reliable parameter estimates. Here, we ask whether it can reproduce and account for the timing properties of motor imagery. Using various simulations, we show that the scalar property of motor imagery can be explained by assuming that the onset and duration of imagined actions are gated by a noisy threshold to conscious access. In other words, trial-to-trial variability in when and for how long motor imagery accesses consciousness suffices to account for the scalar property of motor imagery. In addition to providing an excellent fit to data, this model generates several novel predictions, thus opening new research avenues on the neural and cognitive mechanisms underlying the timing of motor imagery.