Tyler Cluff

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Sensory information from our eyes, skin and muscles helps guide and correct balance. Less appreciated, however, is that delays in the transmission of sensory information between our eyes, limbs and central nervous system can exceed several 10s of milliseconds. Investigating how these time-delayed sensory signals influence balance control is central to(More)
We examined the influence of attentional focus and cognitive load on motor performance in a dynamic stick balancing task during the maintenance of upright posture. Dynamical analyses of postural fluctuations revealed the existence of a drift and correct mechanism, with correlational structure reflecting the demands of the stick balancing task. In contrast,(More)
In this experiment, we examined the extent to which postural control is influenced by visual and cognitive task performance. Fourteen healthy young participants performed a balance task in eyes-open (EO) and delayed visual feedback (DVF) conditions. DVF was presented at delays ranging from 0 to 1200ms in 300ms increments. Cognitive load was implemented by a(More)
Humans possess an impressive ability to generate goal-oriented motor actions to move and interact with the environment. The planning and initiation of these body movements is supported by highly distributed cortical and subcortical circuits. Recent studies, inspired by advanced control theory, highlight similar sophistication when we make online corrections(More)
The probability distributions for changes in transverse plane fingertip speed are Lévy distributed in human pole balancing. Six subjects learned to balance a pole on their index finger over three sessions while sitting and standing. The Lévy or decay exponent decreased as a function of learning, showing reduced decay in the probability for large speed steps(More)
A hallmark of voluntary motor control is the ability to adjust motor patterns for novel mechanical or visuomotor contexts. Recent work has also highlighted the importance of feedback for voluntary control, leading to the hypothesis that feedback responses should adapt when we learn new motor skills. We tested this prediction with a novel paradigm requiring(More)
We studied the dynamics of fingertip displacement series in human pole balancing using recurrence quantification analysis (RQA). The purpose of this research was to determine how the dynamical structure of fingertip fluctuations evolved with learning. Learning was accompanied by increased stability of movement trajectories in spite of a reduced tendency for(More)
A key feature of skilled object control is the ability to correct performance errors. This process is not straightforward for unstable objects (e.g., inverted pendulum or "stick" balancing) because the mechanics of the object are sensitive to small control errors, which can lead to rapid performance changes. In this study, we have characterized joint(More)
Nonlinear dynamical techniques offer a powerful approach for the investigation of physiological time series. Multiscale entropy analyses have shown that pathological and aging systems are less complex than healthy systems and this finding has been attributed to degraded physiological control processes. A similar phenomenon may arise during fatiguing muscle(More)
Theories of motor learning argue that the acquisition of novel motor skills requires a task-specific organization of sensory and motor subsystems. We examined task-specific coupling between motor subsystems as subjects learned a novel stick-balancing task. We focused on learning-induced changes in finger movements and body sway and investigated the effect(More)