Dual-Task and Single-Task Practice Does Not Influence the Attentional Demands of Movement Sequence Representations.

This study examined the attentional demands of movement sequence representations at different temporal points after single- or dual-task practice. The visual-spatial representation encodes the movement based on visual-spatial coordinates such as the target locations. The motor representation encodes the movement in motor coordinates including joint angles and muscle activation patterns.

Across-task binding: The development of a representation in learning a continuous movement sequence.

Across-task binding is defined as the stimulus/response of one task being linked to the response of another task. The purpose of the present experiment was to determine across-task binding in a continuous movement sequence task with an auditory task of high and low pitch tones and the development of a movement sequence representation. According to the two systems theory of sequence learning, we expected that the developed representation in the across-task binding context relies on the multi-dimensional system rather than on the unidimensional system which is restricted to a set of modules where each module processed information along one task/dimension.

Attentional Demand of a Movement Sequence Guided by Visual-Spatial and by Motor Representations.

The objective of the experiment was to assess the change in attentional demands of a movement sequence guided by visual-spatial and motor representations across practice sessions in a dual-task probe paradigm. Participants were randomly assigned to either a 1-day or 2-day practice group. Following acquisition of the motor sequence task, participants first conducted a retention test and then four inter-manual transfer tests under single and dual-task conditions.

The influence of accuracy constraints on bimanual and unimanual sequence learning.

An experiment was designed to determine whether accuracy constraints can influence how unimanual and bimanual motor sequences are produced and learned. The accuracy requirements of the task were manipulated using principles derived from Fitts' Law to create relatively low (ID = 3) and high (ID = 5) accuracy demands. Right-limb dominant participants (N = 28, age = 21.

Movement Sequence Learning: Cognitive Processing Demands to Develop a Response Structure.

An experiment was designed to investigate the impact of a dual-task on the response structure of a 16-element movement sequence. The primary task was to move a lever to targets sequentially presented horizontally on the screen by elbow extension/flexion movements. The secondary task was a simple reaction time task triggered by moving the lever through targets at the middle and the end of the sequence.

Dyad training protocols and the development of a motor sequence representation.

The purpose of the experiment was to determine the extent to which observation and the inter-trial dialogue in a dyad training protocol enhance the development of a movement sequence representation. The task was to reproduce a 1300ms spatial-temporal pattern of elbow extension/flexion movements. An inter-manual transfer design with a retention test and two effector transfer tests was used.

Response biases: the influence of the contralateral limb and head position.

Two experiments were designed to determine response biases resulting from production of force in the contralateral limb and head position. Participants were required to react with one limb while tracking a sinewave template by generating a pattern of force defined by the sinewave with the contralateral limb or watching a cursor move through the sinewave. In Experiment 1, participants had to react with their right or left limb while their head was in a neutral position.

The Cognitive Status of Older Adults: Do Reduced Time Constraints Enhance Sequence Learning?

Research has indicated that older adults perform movement sequences more slowly than young adults. The purpose of the present experiment was to compare movement sequence learning in young and older adults when the time to perform the sequence was extended, and how the elderly's cognitive status (Montreal Cognitive Assessment [MoCA]) interacted with sequence learning. The task was to minimize the difference between a target sequence pattern and the sequence produced by elbow extension-flexion movements.

Bimanual control strategies.

Two tasks (A and B) were designed which required participants to sequentially move through four target positions in a Lissajous display. Task A was designed so that participants could complete the task using either unimanual or bimanual control strategies. Task B was designed so that participants could complete the task using relatively simple or more complex bimanual control strategies.

The simplest acquisition protocol is sometimes the best protocol: performing and learning a 1:2 bimanual coordination task.

An experiment was conducted to determine if the performance and learning of a multi-frequency (1:2) coordination pattern between the limbs are enhanced when a model is provided prior to each acquisition trial. Research has indicated very effective performance of a wide variety of bimanual coordination tasks when Lissajous plots with goal templates are provided, but this research has also found that participants become dependent on this information and perform quite poorly when it is withdrawn. The present experiment was designed to test three forms of modeling (Lissajous with template, Lissajous without template, and limb model), but in each situations, the model was presented prior to practice and not available during the performance of the task.

Intentional Switching Between Bimanual Coordination Patterns.

Previous theoretical and empirical work indicates that intentional changes in a bimanual coordination pattern depends on the stability of the bimanual coordination pattern (Kelso, Schotz, & Schöner, 1988; Scholz & Kelso, 1990). The present experiments retest this notion when online Lissajous displays are provided. Switching to and from in-phase and antiphase and to and from 90° and 270° were tested in Experiment 1.

Do accuracy requirements change bimanual and unimanual control processes similarly?

Unimanual (left and right limbs) and bimanual (in-phase) reciprocal aiming tasks were tested to determine if the control processes used to perform the unimanual aiming tasks were also present in bimanual aiming tasks. Participants were asked to move a cursor as quickly and accurately as possible between the two targets presented in a Lissajous feedback display. The size of the targets created indexes of difficulty (ID) of 3, 4, 5, and 6 and the position of the targets created bimanual and unimanual conditions.

The influence of asymmetric force requirements on a multi-frequency bimanual coordination task.

An experiment was designed to determine the impact of the force requirements on the production of bimanual 1:2 coordination patterns requiring the same (symmetric) or different (asymmetric) forces when Lissajous displays and goal templates are provided. The Lissajous displays have been shown to minimize the influence of attentional and perceptual constraints allowing constraints related to neural crosstalk to be more clearly observed. Participants (N=20) were randomly assigned to a force condition in which the left or right limb was required to produce more force than the contralateral limb.

Hemispheric asymmetries of a motor memory in a recognition test after learning a movement sequence.

Two experiments utilizing a spatial-temporal movement sequence were designed to determine if the memory of the sequence is lateralized in the left or right hemisphere. In Experiment 1, dominant right-handers were randomly assigned to one of two acquisition groups: a left-hand starter and a right-hand starter group. After an acquisition phase, reaction time (RT) was measured in a recognition test by providing the learned sequential pattern in the left or right visual half-field for 150ms.

Life span changes: Performing a continuous 1:2 bimanual coordination task.

The experiment was conducted to determine the influence of mirror movements in bimanual coordination during life span. Children, young adults, and older adults were instructed to perform a continuous 1:2 bimanual coordination task by performing flexion-extension wrist movements over 30s where symmetrical and non-symmetrical coordination patterns alternate throughout the trial. The vision of the wrists was covered and Lissajous-feedback was provided online.

Continuous scanning trials:Transitioning through the attractor landscape.

Bimanual 1:1 coordination patterns other than in-phase (0°) and anti-phase (180°) have proven difficult to perform even with extended practice. The difficulty has traditionally been attributed to phase attraction that draws the coordination between the limbs towards the bimanual patterns of in-phase and anti-phase and variability associated with the activation and associated proprioceptive signals of non-homologous muscles via crossed and uncrossed cortical pathways. However, recent experiments have demonstrated that a wide range of relative phase and multi-frequency coordination patterns can be effectively produced with only a few minutes of practice when Lissajous or online relative phase information is provided.

Symmetrical and asymmetrical influences on force production in 1:2 and 2:1 bimanual force coordination tasks.

Results from a recent experiment (Kennedy et al. in Exp Brain Res 233:181-195, 2015) indicated consistent and identifiable distortion of the left limb forces that could be attributable to the production of right limb forces during a multi-frequency bimanual force task. However, distortions in the forces produced by the right limb that could be attributable to the production of force in the left limb were not observed.

Perception and action influences on discrete and reciprocal bimanual coordination.

For nearly four decades bimanual coordination, "a prototype of complex motor skills" and apparent "window into the design of the brain," has been intensively studied. Past research has focused on describing and modeling the constraints that allow the production of some coordination patterns while limiting effective performance of other bimanual coordination patterns. More recently researchers have identified a coalition of perception-action constraints that hinder the effective production of bimanual skills.

A novel approach to enhancing limb control in older adults.

Two recent experiments have demonstrated that young adult participants were able to make faster and more harmonic movements in a typical reciprocal Fitts task (ID = 6) following a practice session of sine wave tracking (Boyle et al. in Exp Brain Res 223:377-387, 2012; J Mot Behav 46:277-285, 2014). The purpose of the present experiment was to replicate these findings with a young adult population (age 18-25) and determine whether sine wave tracking also enhances goal-directed limb movements in an older adult population (age 65-90).

The impact of concurrent visual feedback on coding of on-line and pre-planned movement sequences.

The purpose of this study was to determine the extent to which participants could effectively switch from on-line (OL) to pre-planned (PP) control (or vice versa) depending on previous practice conditions and whether concurrent visual feedback was available during transfer testing. The task was to reproduce a 2000 ms spatial-temporal pattern of a sequence of elbow flexions and extensions. Participants were randomly assigned to one of two practice conditions termed OL or PP.

Bimanual force control: cooperation and interference?

Three experiments were designed to determine the level of cooperation or interference observed from the forces generated in one limb on the forces exhibited by the contralateral limb when one or both limbs were producing a constant force (Experiment 1), one limb was producing a dynamic force while the other limb was producing a constant force (Experiment 2), and both limbs were producing dynamic force patterns (Experiment 3). The results for both Experiments 1 and 2 showed relatively strong positive time series cross correlations between the left and right limb forces indicating increases or decreases in the forces generated by one limb resulted in corresponding changes in the forces produced by the homologous muscles of the contralateral limb. Experiment 3 required participants to coordinate 1:1 and 1:2 rhythmical bimanual force production tasks when provided Lissajous feedback.

A cognitive framework for explaining serial processing and sequence execution strategies.

Behavioral research has produced many task-specific cognitive models that do not say much about the underlying information-processing architecture. Such an architecture is badly needed to better understand how cognitive neuroscience can benefit from existing cognitive models. This problem is especially pertinent in the domain of sequential behavior where behavioral research suggests a diversity of cognitive processes, processing modes and representations.

Rhythmical bimanual force production: homologous and non-homologous muscles.

The experiment was designed to determine participants' ability to coordinate a bimanual multifrequency pattern of isometric forces using homologous or non-homologous muscles. Lissajous feedback was provided to reduce perceptual and attentional constraints. The primary purpose was to determine whether the activation of homologous and non-homologous muscles resulted in different patterns of distortions in the left limb forces that are related to the forces produced by the right limb.

The sine wave protocol: decrease movement time without increasing errors.

Practice tracking a sine wave template has been shown (J. B. Boyle, D.

Interlimb practice and aging: coding a simple movement sequence.

Unlabelled: BACKGROUND/STUDY CONTEXT: The purpose was to determine if aging interacts with the coding of a simple spatial-temporal movement sequence.

Methods: An interlimb practice paradigm (24 participants; 12 young adults [age: 23-29]; 12 old adults [age: 65-78]) was designed to determine the coordinate system (visual-spatial/motor) that is used to code the movement sequence. Practice was scheduled over 2 days involving either the same visual-spatial or the same motor coordinates.