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The influence of temporal predictability on express visuomotor responses
Samuele Contemori1, Gerald E Loeb2, Brian D Corneil3,4,5
1Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Australia.
Journal of Neurophysiology
|December 28, 2020
Summary
Predictable target timing, not motion, facilitates rapid human visuomotor responses (SLRs). An internal timer primes the superior colliculus for these express responses, improving detection rates.
Area of Science:
- Neuroscience
- Motor Control
- Human Physiology
Background:
- Humans exhibit rapid visuomotor responses (SLRs) under 100ms, proposed to involve subcortical pathways via the superior colliculus.
- Previous detection of SLRs has been inconsistent, limiting understanding of their neural mechanisms.
- A recent paradigm reportedly elicits SLRs in all participants, suggesting a potential breakthrough in studying these responses.
Purpose of the Study:
- To reproduce the efficacy of a paradigm for eliciting stimulus-locked responses (SLRs).
- To test whether target timing predictability, rather than motion, drives SLR generation.
- To investigate the neural mechanisms underlying express visuomotor responses.
Main Methods:
- Surface electromyogram (EMG) recorded from shoulder muscles during target interception tasks.
- Experiment 1: Compared SLRs to temporally predictable versus unpredictable targets.
- Experiment 2: Compared SLRs to transiently presented versus sustained moving targets.
Main Results:
- Predictably timed targets elicited significantly more frequent and stronger SLRs than unpredictably timed targets.
- Transiently presented targets produced larger and earlier SLRs compared to sustained moving targets.
- Target motion kinematics were not critical for facilitating SLR expression.
Conclusions:
- The effectiveness of the SLR elicitation paradigm relies on temporal predictability, not target motion.
- SLR generation is likely mediated by an internal timing mechanism, possibly in the cerebral cortex.
- The superior colliculus can be primed via cortical top-down projections to generate express stimulus-driven motor responses.
