The kinematics of motor imagery: Comparing the dynamics of real and virtual movements

Rodrı́guez, Manuel; Llanos, Catalina; Sabaté, Magdalena

doi:10.1016/j.neuropsychologia.2008.10.009

Cited by 18 publications

(9 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our results, supporting the existence of continuous motor planning, are also consistent with results of motor imagery studies which demonstrated that motor imagery is a time-consuming process whose durations (Jeannerod and Decéty, 1995; Roth et al, 1996; Rodriguez et al, 2008, 2009; Guillot et al, 2012) and kinematic profiles (Papaxanthis et al, 2012; Karklinsky and Flash, 2015) are closely correlated with those of executed movements. Under the hypothesis that motor imagery is equivalent to motor planning (Jeannerod and Decéty, 1995; Jeannerod, 1995), the fact that motor imagery is not instantaneous and evolves through time provides another argument in favor of our conjecture that movement planning is a continuous process.…”

Section: Discussionsupporting

confidence: 90%

The Effects of Reducing Preparation Time on the Execution of Intentionally Curved Trajectories: Optimization and Geometrical Analysis

Kohen

Karklinsky

Meirovitch

et al. 2017

Front. Hum. Neurosci.

View full text Add to dashboard Cite

When subjects are intentionally preparing a curved trajectory, they are engaged in a time-consuming trajectory planning process that is separate from target selection. To investigate the construction of such a plan, we examined the effect of artificially shortening preparation time on the performance of intentionally curved trajectories using the Timed Response task that enforces initiation of movements prematurely. Fifteen subjects performed obstacle avoidance movements toward one of four targets that were presented 25 or 350 ms before the “go” signal, imposing short and long preparation time conditions with mean values of 170 ms and 493 ms, respectively. While trajectories with short preparation times showed target specificity at their onset, they were significantly more variable and showed larger angular deviations from the lines connecting their initial position and the target, compared to the trajectories with long preparation times. Importantly, the trajectories of the short preparation time movements still reached their end-point targets accurately, with comparable movement durations. We hypothesize that success in the short preparation time condition is a result of an online control mechanism that allows further refinement of the plan during its execution and study this control mechanism with a novel trajectory analysis approach using minimum jerk optimization and geometrical modeling approaches. Results show a later agreement of the short preparation time trajectories with the optimal minimum jerk trajectory, accompanied by a later initiation of a parabolic segment. Both observations are consistent with the existence of an online trajectory planning process.Our results suggest that when preparation time is not sufficiently long, subjects execute a more variable and less optimally prepared initial trajectory and exploit online control mechanisms to refine their actions on the fly.

show abstract

Section: Discussionsupporting

confidence: 90%

The Effects of Reducing Preparation Time on the Execution of Intentionally Curved Trajectories: Optimization and Geometrical Analysis

Kohen

Karklinsky

Meirovitch

et al. 2017

Front. Hum. Neurosci.

View full text Add to dashboard Cite

show abstract

“…In previous experiments, changes in movement duration were attributed either to a variable attention load in discrete movements [23] or to a greater elaboration requirement when the movement direction is changing in continuous movements [24]. In other words, these investigations might suggest that a change of direction may induce an increase in attention resources and, thus, longer durations.…”

Section: Resultsmentioning

confidence: 95%

“…Note, however, that the amount of path curvature is not the only parameter that could influence movement duration. Changes in mental and/or actual movement durations could be attributed either to a variable attention load in discrete movements [23] or to a greater elaboration requirement when movement direction changes in continuous movements [24]. Experiment 2 was designed to test whether curvature per se or attention requirements in changing movement direction modulate the speed of mental movements.…”

Section: Introductionmentioning

confidence: 99%

The Relation between Geometry and Time in Mental Actions

et al. 2012

View full text Add to dashboard Cite

Mental imagery is a cognitive tool that helps humans take decisions by simulating past and future events. The hypothesis has been advanced that there is a functional equivalence between actual and mental movements. Yet, we do not know whether there are any limitations to its validity even in terms of some fundamental features of actual movements, such as the relationship between space and time. Although it is impossible to directly measure the spatiotemporal features of mental actions, an indirect investigation can be conducted by taking advantage of the constraints existing in planar drawing movements and described by the two-thirds power law (2/3PL). This kinematic law describes one of the most impressive regularities observed in biological movements: movement speed decreases when curvature increases. Here, we compared the duration of identical actual and mental arm movements by changing the constraints imposed by the 2/3PL. In the first two experiments, the length of the trajectory remained constant, while its curvature (Experiment 1) or its number of inflexions (Experiment 2) was manipulated. The results showed that curvature, but not the number of inflexions, proportionally and similarly affected actual and mental movement duration, as expected from the 2/3PL. Two other control experiments confirmed that the results of Experiment 1 were not attributable to eye movements (Experiment 3) or to the perceived length of the displayed trajectory (Experiment 4). Altogether, our findings suggest that mental movement simulation is tuned to the kinematic laws characterizing actions and that kinematics of actual and mental movements is completely specified by the representation of their geometry.

show abstract

“…Several investigations have provided strong evidence for various neurocognitive similarities between mental and sensorimotor states. For instance, behavioural studies have shown that the required time to produce a specific movement is tightly correlated with the required time to mentally simulate the same movement [1]–[10]. Furthermore, autonomic activation increases proportionally to the mental effort produced during imagined movements [11]–[13] and appropriate mental training enhances motor performance [14]–[19].…”

Section: Introductionmentioning

confidence: 99%

Mental Representation of Arm Motion Dynamics in Children and Adolescents

et al. 2013

View full text Add to dashboard Cite

Motor imagery, i.e., a mental state during which an individual internally represents an action without any overt motor output, is a potential tool to investigate action representation during development. Here, we took advantage of the inertial anisotropy phenomenon to investigate whether children can generate accurate motor predictions for movements with varying dynamics. Children (9 and 11 years), adolescents (14 years) and young adults (21 years) carried-out actual and mental arm movements in two different directions in the horizontal plane: rightwards (low inertia) and leftwards (high inertia). We recorded and compared actual and mental movement times. We found that actual movement times were greater for leftward than rightward arm movements in all groups. For mental movements, differences between leftward versus rightward movements were observed in the adults and adolescents, but not among the children. Furthermore, significant differences between actual and mental times were found at 9 and 11 years of age in the leftward direction. The ratio R/L (rightward direction/leftward direction), which indicates temporal differences between low inertia and high inertia movements, was inferior to 1 at all ages, except for the mental movements at 9 years of age, indicating than actual and mental movements were shorter for the rightward than leftward direction. Interestingly, while the ratio R/L of actual movements was constant across ages, it gradually decreased with age for mental movements. The ratio A/M (actual movement/mental movement), which indicates temporal differences between actual and mental movements, was near to 1 in the adults' groups, denoting accurate mental timing. In children and adolescents, an underestimation of mental movement times appeared for the leftward movements only. However, this overestimation gradually decreased with age. Our results showed a refinement in the motor imagery ability during development. Action representation reached maturation at adolescence, during which mental actions were tightly related to their actual production.

show abstract

The kinematics of motor imagery: Comparing the dynamics of real and virtual movements

Cited by 18 publications

References 37 publications

The Effects of Reducing Preparation Time on the Execution of Intentionally Curved Trajectories: Optimization and Geometrical Analysis

The Effects of Reducing Preparation Time on the Execution of Intentionally Curved Trajectories: Optimization and Geometrical Analysis

The Relation between Geometry and Time in Mental Actions

Mental Representation of Arm Motion Dynamics in Children and Adolescents

Contact Info

Product

Resources

About