Modeling the Maturation of Grip Selection Planning and Action Representation: Insights from Typical and Atypical Motor Development.

Ian Fuelscher,Jacqueline Williams,Peter G Enticott,Kate Wilmut,Christian Hyde

doi:10.3389/fpsyg.2016.00108

Ian Fuelscher, Jacqueline Williams + Show 3 more

Open Access

https://doi.org/10.3389/fpsyg.2016.00108

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Abstract

We investigated the purported association between developmental changes in grip selection planning and improvements in an individual’s capacity to represent action at an internal level [i.e., motor imagery (MI)]. Participants were groups of healthy children aged 6–7 years and 8–12 years respectively, while a group of adolescents (13–17 years) and adults (18–34 years) allowed for consideration of childhood development in the broader context of motor maturation. A group of children aged 8–12 years with probable DCD (pDCD) was included as a reference group for atypical motor development. Participants’ proficiency to generate and/or engage internal action representations was inferred from performance on the hand rotation task, a well-validated measure of MI. A grip selection task designed to elicit the end-state comfort (ESC) effect provided a window into the integrity of grip selection planning. Consistent with earlier accounts, the efficiency of grip selection planning followed a non-linear developmental progression in neurotypical individuals. As expected, analysis confirmed that these developmental improvements were predicted by an increased capacity to generate and/or engage internal action representations. The profile of this association remained stable throughout the (typical) developmental spectrum. These findings are consistent with computational accounts of action planning that argue that internal action representations are associated with the expression and development of grip selection planning across typical development. However, no such association was found for our sample of children with pDCD, suggesting that individuals with atypical motor skill may adopt an alternative, sub-optimal strategy to plan their grip selection compared to their same-age control peers.

Highlights

In general terms, motor planning reflects the process of selecting a movement plan from an infinite number of solutions in order to achieve a desired end-state (Rosenbaum et al, 1992)
Our data support computational accounts of motor planning, which suggest that internal action representations are associated with both the expression and development of mature grip selection planning. No such association was found for our atypically developing children. We argue that this finding provides preliminary evidence that children with probable’ DCD (pDCD) may be less reliant on internal action representations than their age-matched control counterparts when planning their grasping movements
Since computational modeling suggests that optimal grip selection planning is dependent on one’s ability to effectively generate and/or engage internal action representations (Rosenbaum et al, 1995, 2001, 2014; Johnson, 2000; Glover, 2004), we argue that this non-monotonic maturation may be subserved, at least partly, by a greater capacity to generate and/or engage internal action representations

Summary

Introduction

Motor planning reflects the process of selecting a movement plan from an infinite number of solutions in order to achieve a desired end-state (Rosenbaum et al, 1992). Neuro-computational modeling suggests that the intended movement, including its terminal location, may be implicitly simulated via internal (neural) representations of the forthcoming action prior to movement execution. To simulate the intended action, the central nervous system is thought to use an efferent copy of the impending motor command (i.e., internal action representations) to predict the sensory consequences of an action given the current and the desired endstate of the limb (Wolpert and Kawato, 1998; Johnson, 2000; Wolpert and Ghahramani, 2000; Glover, 2004). This view is supported by recent imaging data which suggests that this process may call upon similar systems that are active during movement preparation, including parietalcerebellar structures and premotor cortices (see Hétu et al, 2013 for a review)

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