Studying action representation in children via motor imagery

The use of motor imagery is a widely used experimental paradigm for the study of cognitive aspects of action planning and control in adults. Furthermore, there are indications that motor imagery provides a window into the process of action representation. These notions complement internal model theory suggesting that such representations allow predictions (estimates) about the mapping of the self to parameters of the external world; processes that enable successful planning and execution of action. The ability to mentally represent action is important to the development of motor control. This paper presents a critical review of motor imagery research conducted with children (typically developing and special populations) with focus on its merits and possible shortcomings in studying action representation. Included in the review are age-related findings, possible brain structures involved, experimental paradigms, and recommendations for future work. The merits of this review are associated with the apparent increasing attraction for using and studying motor imagery to understand the developmental aspects of action processing in children.     

言语-表象型认知风格与外显、内隐记忆的关系

研究探讨言语-表象维度认知风格对外昱、内隐记忆效果的影响。实验采用不同认知风格（言语型和表象型）的被试,以抽象名词和具体名词为测验材料,运用了Jacoby加工分离程序。结果发现：言语-表象维度认知风格对内隐记忆效果的影响与外显记忆不同。（1）表象型被试和言语型被试在识记抽象名词时外显记忆成绩差异显著;（2）言语型-表象型认知风格没有导致内隐记忆的个体差异。     

Effects of imagery training on cognitive performance and use of physiological measures as an assessment tool of mental effort

The effectiveness of motor imagery training on cognitive performance was examined and the physiological mechanisms involved in the contribution of mental practice to motor learning were considered. The subject's mental effort during motor imagery was assessed by using psychophysiological measures and particularly eye blink activity as an 'indirect' measurement of subjects' attention. An electronic flight simulation program (Multiple Attribute Task Battery--MATB) was used to assess performance. Twenty healthy volunteers participated in the study divided in two groups: the control group and the imagery-training group. The subjects of the imagery group were asked for additional imagery training. The subjects of the actual performing group were asked additionally to passively observe the task in order to have equal time of exposure to the task. Performance scores and physiological parameters such as heart rate, respiratory rate, eye blinking activity and muscular activity were recorded during all sessions. The results revealed significantly higher performance level of the imagery-training group than the control group. Heart rate and respiratory rate significantly increased during imagery sessions compared to rest. A slight electromyographic activity was observed during the imagination of movement. Our findings support the notion that mental practice improves motor performance in a task where spatiotemporal or dynamic control of the action is highly required. The effects of mental practice on motor performance could be explained by the existence of a top-down mechanism based on the activation of a central representation of the movements, since the vegetative activation during motor imagery seems to be centrally controlled.     

Reorganization of functional and effective connectivity during real-time fMRI-BCI modulation of prosody processing

Mechanisms of cortical reorganization underlying the enhancement of speech processing have been poorly investigated. In the present study, we addressed changes in functional and effective connectivity induced in subjects who learned to deliberately increase activation in the right inferior frontal gyrus (rIFG), and improved their ability to identify emotional intonations by using a real-time fMRI Brain-Computer Interface. At the beginning of their training process, we observed a massive connectivity of the rIFG to a widespread network of frontal and temporal areas, which decreased and lateralized to the right hemisphere with practice. Volitional control of activation strengthened connectivity of this brain region to the right prefrontal cortex, whereas training increased its connectivity to bilateral precentral gyri. These findings suggest that changes of connectivity in a functionally specific manner play an important role in the enhancement of speech processing. Also, these findings support previous accounts suggesting that motor circuits play a role in the comprehension of speech.     

Developmental dyspraxia and developmental coordination disorder

This article discusses the role developmental dyspraxia plays in developmental coordination disorder (DCD), based upon a review of literature on apraxia, developmental dyspraxia, and DCD. Apraxia and dyspraxia have often been equated with DCD. However, it is argued that apraxia and dyspraxia primarily refer to the problems of motor sequencing and selection, which not all children with DCD exhibit. The author proposes to distinguish developmental dyspraxia from DCD. Other issues discussed include the assessment, etiology, and treatment of developmental dyspraxia and DCD, and the relationship between DCD and learning disabilities. A research agenda is offered regarding future directions to overcome current limitation.     

The influence of geographic region on the seasonality of early motor development

This investigation was conducted to determine whether the strong seasonality effect on infant motor development that has been noted in moderate climates would be replicated with infants born in a geographic region with more extreme conditions. One hundred and forty-five full-term infants (72 males, 73 females) born in Edmonton, alberta were assessed using the Alberta Infant Motor Scale (AIMS) at 7 months of age. No seasonality effects on the AIMS total scores or the prone, supine, sitting, or standing subsection scores were detected. A weak and statistically non-significant correlation was obtained between the average monthly AIMS scores and the average monthly temperatures 7 months after birth. These results suggest that extreme climatic conditions in urban geographic regions may dampen effects of season of birth on infant motor development.     

Predicting preschool motor and cognitive performance in appropriate-for-gestational-age children born at ≤ 32 weeks gestation

Although many follow-up studies have been performed on preterm infants, little attention has been devoted to prediction of motor skills in the preschool or school years. We studied the relationship of performance on the Bayley Scales of Infant Development at a mean corrected age of 21 months to performance on the McCarthy Scales of Children's Abilities at a mean corrected age of 44.7 months for 43 appropriate-for-gestational-age (AGA) children born at ≤ 32 weeks gestation. Motor scores were stable over time with a significant correlation between the Bayley Psychomotor Developmental Index (PDI) and the McCarthy Motor subscale (r = 0.60; p = 0.0001). Scores of cognitive abilities also showed a significant correlation between the Bayley Mental Developmental Index (MDI) and the McCarthy General Cognitive Index (r = 0.42; p = 0.009). Small-for-gestational-age (SGA), very low-birthweight (≤ 1500 grams) children scored lower on the McCarthy General Cognitive Index (p = 0.01) and on the Motor subscale (p = 0.047) than the AGA children. We concluded that motor performance of AGA children born at ≤ 32 weeks gestation is stable from toddlerhood to preschool age. We suggest that SGA children be excluded from studies of motor performance of prematurely born children.     

The uses of mental imagery in athletics: An overview

This article surveys the extant literature on mental imagery as used in athletics for performance enhancement, arousal regulation, affective and cognitive modification, and rehabilitation. For each category of use, applications are discussed, an overview of the empirical and case-study research findings is presented, and the research is critiqued. A concluding section recommends directions for future research on uses of mental imagery in athletics.