Local and global stabilization of coordination by sensory information

Abstract

In studies of rhythmic coordination, where sensory information is often generated by an auditory stimulus, spatial and temporal variability are known to decrease at points in the movement cycle coincident with the stimulus, a phenomenon known as anchoring (Byblow et al. 1994). Here we hypothesize that the role of anchoring may be to globally stabilize coordination under conditions in which it would otherwise undergo a global coordinative change such as a phase transition. To test this hypothesis, anchoring was studied in a bimanual coordination paradigm in which either inphase or antiphase coordination was produced as auditory pacing stimuli (and hence movement frequency) were scaled over a wide range of frequencies. Two different anchoring conditions were used: a single-metronome condition, in which peak amplitude of right finger flexion coincided with the auditory stimulus; and a double-metronome condition, in which each finger reversal (flexion and extension) occurred simultaneously with the auditory stimuli. Anchored reversal points displayed lower spatial variation than unanchored reversal points, resulting in more symmetric phase plane trajectories in the double- than the single-metronome condition. The global coordination dynamics of the double-metronome condition was also more stable, with transitions from antiphase to inphase occurring less often and at higher movement frequencies than in the single-metronome condition. An extension of the Haken-Kelso-Bunz model of bimanual coordination is presented briefly which includes specific coupling of sensory information to movement through a process we call parametric stabilization. The parametric stabilization model provides a theoretical account of both local effects on the individual movement trajectories (anchoring) and global stabilization of observed coordination patterns, including the delay of phase transitions.

The human dynamic clamp as a paradigm for social interaction

“…The HDC paradigm is open to any sensory modality, and may be adapted to any behavioral task. Moreover, a wide variety of processes such as the recruitment and annihilation of biomechanical degrees of freedom (51), parametric stabilization (38), sensory anchoring (37), and so forth, can be incorporated into the HDC. It seems possible that the same approach can be extended to other situations such as gaze interaction (52), imitation games (53,54), and game theory (55), to name a few.…”

Goal‐based representation in repetitive bimanual movements

“…The influence of event-based goals on rhythmic movements has also been emphasized in recent studies by Kelso and colleagues (Fink et al, 2000;Kelso, Fink, DeLaplain, & Carson, 2001). Measures of relative phase are more stable when a pacing metronome is used to present two beats per cycle compared to when only a single sound is presented each cycle.…”

“…While much of this work has focused on biomechanical factors (e.g., activation of homologous muscles), recent studies have pointed to the importance of higher level variables such as attention (Pellecchia & Turvey, 2001) and goal-based representations (Fink et al, 2000;Mechsner et al, 2001). Defining what is meant by the term "goal" can be difficult.…”

Multilevel coordination stability: Integrated goal representations in simultaneous intra-personal and inter-agent coordination

“…The phenomenon known as 'anchoring' (Beek, 1989;Byblow, Carson, & Goodman, 1994;Fink, Foo, Jirsa, & Kelso, 2000;Roerdink, Ophoff, Peper, & Beek, 2008) provides a specific mechanism that may facilitate coordination stability especially during ABS with auditory feedback. Anchoring occurs when cyclic movements (e.g., juggling) are timed with reference to a discrete point within each cycle.…”

“…Such anchor points, which often coincide with salient movement transitions, can be viewed as "intentional attractors" (Beek, 1989, p. 183) that provide task-specific information that assists in reducing kinematic variability around movement transition points as well as stabilizing entire movement cycles (see Roerdink et al, 2008). The information that is available at anchor points thus varies according to the task, and, moreover, it can be associated both with self-generated events (e.g., ball release in juggling; Beek, 1989) and with externally controlled events (e.g., the tones of an auditory pacing signal; Fink et al, 2000). When auditory feedback is present during ABS, the feedback tones triggered by taps may serve as self-generated anchoring events.…”