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Mental representation of arm motion dynamics in children and adolescents.

Crognier L, Skoura X, Vinter A, Papaxanthis C - PLoS ONE (2013)

Bottom Line: We found that actual movement times were greater for leftward than rightward arm movements in all groups.Furthermore, significant differences between actual and mental times were found at 9 and 11 years of age in the leftward direction.However, this overestimation gradually decreased with age.

View Article: PubMed Central - PubMed

Affiliation: Université de Bourgogne, Unité de Formation et de Recherche en Sciences et Techniques des Activités Physiques et Sportives, Dijon, France.

ABSTRACT
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.

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Average values (+SE) of the index of mental performance (M/P) for the four age-groups.Stars indicate significant differences between right and left directions.
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pone-0073042-g004: Average values (+SE) of the index of mental performance (M/P) for the four age-groups.Stars indicate significant differences between right and left directions.

Mentions: Fig. 4 shows the average values (+SE) of the ratio A/M. In adults, these values were near to 1, denoting accurate mental representations for both right (low inertia) and left (high inertia) directions. In children, an overestimation of actual movements appeared for the leftward movements. However, this overestimation gradually decreased with age. The ANOVA revealed an interaction effect between age and direction (F3,68 = 10.84, n2p = .32, p<0.0001). Post hoc analysis showed significant differences between rightward and leftward movements at 9 (p = 0.001) and 11 years of age (p = 0.01), but not in the 14-year-olds (p = 0.17) and in adults (p = 0.71). Furthermore, the ratio A/M in leftward direction significantly decreased with age (for all comparisons, p<0.05; except for 9 yrs versus 11 yrs and 14 yrs versus adults, for both p>0.3).


Mental representation of arm motion dynamics in children and adolescents.

Crognier L, Skoura X, Vinter A, Papaxanthis C - PLoS ONE (2013)

Average values (+SE) of the index of mental performance (M/P) for the four age-groups.Stars indicate significant differences between right and left directions.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3757012&req=5

pone-0073042-g004: Average values (+SE) of the index of mental performance (M/P) for the four age-groups.Stars indicate significant differences between right and left directions.
Mentions: Fig. 4 shows the average values (+SE) of the ratio A/M. In adults, these values were near to 1, denoting accurate mental representations for both right (low inertia) and left (high inertia) directions. In children, an overestimation of actual movements appeared for the leftward movements. However, this overestimation gradually decreased with age. The ANOVA revealed an interaction effect between age and direction (F3,68 = 10.84, n2p = .32, p<0.0001). Post hoc analysis showed significant differences between rightward and leftward movements at 9 (p = 0.001) and 11 years of age (p = 0.01), but not in the 14-year-olds (p = 0.17) and in adults (p = 0.71). Furthermore, the ratio A/M in leftward direction significantly decreased with age (for all comparisons, p<0.05; except for 9 yrs versus 11 yrs and 14 yrs versus adults, for both p>0.3).

Bottom Line: We found that actual movement times were greater for leftward than rightward arm movements in all groups.Furthermore, significant differences between actual and mental times were found at 9 and 11 years of age in the leftward direction.However, this overestimation gradually decreased with age.

View Article: PubMed Central - PubMed

Affiliation: Université de Bourgogne, Unité de Formation et de Recherche en Sciences et Techniques des Activités Physiques et Sportives, Dijon, France.

ABSTRACT
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 MeSH