Spatial and Timing Regulation of Upper-Limb Movements in Rhythmic Tasks

Motor control;rhythmic movement;not listed

Nickl, RobertSarma, Sridevi V ;

Johns Hopkins University

关键词: Motor control;    rhythmic movement;    not listed;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/59978/nicklThesis_toSubmit_PDFA.pdf?sequence=3&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Rhythmic movement is vital to humans and a foundation of such activities as locomotion, handwriting, and repetitive tool use.The spatiotemporal regularity characterizing such movements reflects a level of automaticity and coordination that is believed to emerge from mutually inhibitory or other pattern generating neural networks in the central nervous system.Although many studies have provided descriptions of this regularity and have illuminated the types of sensory information that influence rhythmic behavior, an understanding of how thebrain uses sensory feedback to regulate rhythmic behavior on a cycle-by-cycle basis has been elusive.This thesis utilizes the model task of paddle juggling, or vertical ball bouncing, to address how three types of feedback---visual, auditory, and haptic---contribute to spatial and temporal regulation of rhythmic upper-limb movements.We use a multi-level approach in accordance with the well-known dictum of Marr and Poggio.The crux of this thesis describes a method and suite of experiments to understand how the brain uses visual, audio, and haptic feedback to regulate spatial or timing regularity, and formulate acycle-by-cycle description of this control: to wit, the nature and algorithms of sensory-feedback guided regulation.Part I motivates our interest in this problem, by discussing the biological ``hardware;;;; that the nervous system putatively employs in these movements, and reviewing insights from previous studies of paddle juggling that suggest how the ``hardware;;;; may manifest itself in these behaviors.The central experimental approach of this thesis is to train participants to perform the paddle juggling task with spatiotemporal regularity (in other words, to achieve limit-cycle behavior), and then interrogate how the brain applies regulates closed-loop performance by perturbing task feedback.In Part II, we review the development of a novel hard-real-time virtual-reality juggling simulator that enabled precise spatial and temporal feedback perturbations.We then outline the central experimental approach, in which we perturb spatial feedback of the ball at apex phase (vision), and timing feedback of collision- (audio and haptic) and apex-phase events to understand spatial and timing regulation.Part III describes two experiments that yield the main research findings of this thesis.In Experiment 1, we use a sinusoidal-perturbation-based system identification approach to determine that spatial and timing feedback are used in two dissociable and complementary control processes: spatial error correction and temporal synchronization.In Experiment 2, a combination of sinusoidal and step perturbations is used to establish that these complementary processes obey different dynamics.Namely, spatial correction is a proportional-integral process based on a one-step memory of feedback, while temporal synchronization is a proportional process that is dependent only on the most recent feedback.We close in Part IV with a discussion of how insights and approaches from this thesis can lead to improved rehabilitation approaches and understanding of the physiological basis of rhythmic movement regulation.