Jane E. Clark - US grants

The overall goal of this research is to understand the relationship between
perception and action in the development of infant postural control.
Although the development of posture and locomotion has been well
documented, only recently has an understanding of the processes that
underlie these changes been sought. This project examines
perception-action coupling as one of the processes that may contribute to
the observed changes. The research is designed to examine the relationship
between perception and posture in three ways. First, we propose to study
infants' postural development longitudinally from the onset of sitting to
three months after the onset of independent walking. Second, we focus on
the role somatosensation plays in postural control. And third, we measure
the coupling relationship between somatosensory input and the infant's
postural responses. Infants will be tested sitting and standing in one of
3 conditions: touching a fixed bar with the hand, no touch (hands free),
or touching a gently moving bar. Relationships between the excursions of
the head, center of mass, and center of pressure as well as forces applied
at the hand will be analyzed. Data are expected to provide critical
information about the study of normal infant postural development as well
as to lay a foundation for understanding those infants with abnormal or
delayed postural development.

DESCRIPTION (provided by applicant): The long-term objective of this research program is to understand the underlying mechanisms of Developmental Coordination Disorder (DCD) and to provide a scientific basis for the evaluation, and interventions of children with this disorder. In elementary school, children with DCD are estimated to comprise up to 6 percent of the population (APA, 1994). These children are at risk for poor academic achievement, socio-emotional difficulties, and long-term health problems due to their lack of participation in physical activities. Previous work on children with DCD has focused primarily on perceptual or task deficits. This proposal examines the hypothesis that children with DCD have problems with the relationship between perception and action and more specifically with the ability to adapt this relationship to new environments and tasks (referred to as adaptive sensorimotor control). In this project, we combine behavioral and computational approaches to investigate this relationship in 7-year-old children with and without DCD in stable and changing sensorimotor environments. Four experimental paradigms are used (a visuomotor drawing task, two postural tasks, one with a driving visual stimulus and another with a driving somatosensory stimulus, and an auditory bilateral tapping task). Thus, we examine the children across multiple motor tasks (drawing, posture, tapping), varying modalities (visual, touch, auditory), and varying time-scales (real-time, short-term adaptation or learning and developmental-time). Such experimental variations are included to address the issue of heterogeneity in this population and more specifically the claim that there are subtypes of DCD that may be task and/or modality dependent for identification. The specific aims of this proposal are to behaviorally and computationally: 1) Characterize the sensorimotor relationships across four tasks. We hypothesize that children with DCO will have less well-defined sensorimotor deficits in all tasks as indexed by measures of spatial and temporal accuracy and variability. Individually, children with DCD will show differential sensorimotor deficits across tasks indicative of the heterogeneity (and possible subtypes) of this population. 2) Investigate the learning of novel internal models under gradual and step-like changes in sensorimotor relationships across four tasks. We hypothesize that children with DCD will be less able to adapt to changes as indexed by time-course, spatial and temporal accuracy and variability measures. Individually, children with DCD will demonstrate differential effects with the abrupt and gradual changes reflecting different underlying mechanisms. 3) Investigate sensorimotor switching across four tasks. We hypothesize that children with DCD will demonstrate an averaging between sensorimotor relationships and/or take longer to stabilize their sensorimotor performance after experiencing a second novel sensorimotor relationship. And 4) Characterize the developmental changes in sensorimotor relationships and adaptations across four tasks after two years. We hypothesize that children with DCD will continue to show broad and non-adaptive sensorimotor tuning as indexed by measures in experiments related to specific aims #1 -3. Taken together, the information from these specific aims will lay the groundwork for future intervention studies as well as further investigation into the underlying mechanisms of this movement disorder.

[unreadable] DESCRIPTION (provided by applicant): Human movement has been a large window into the functioning of the nervous system. Behavioral scientists have had major accomplishments, such as documenting movement milestones in human development and establishing a relationship between brain and behavior in typical and atypical populations. These measurements are performed today with a cornucopia of sophisticated techniques, ranging from infrared and video to wireless sensor networks. However, despite the tremendous progress on measuring human movement, we still don't fully understand, for example, motor decline in elderly people or Parkinson's disease during daily living activities at home and the workplace; or how atypical social interaction in autism or developmental coordination disorder are manifested in body gestures. Why can't we yet deal with problems of such nature? It is clear that the problems mentioned above have characteristics that are beyond the state of the art or any single discipline. Thus, we propose a novel, interdisciplinary, and multi-level motion understanding tool to extract multi-scaled, nested representations of transitive and intransitive actions and communicative actions at different levels of abstraction at the "individual" and "workgroup" levels. Our specific aim is to develop a Human Action Language (HAL) tool, a tool for describing and understanding human actions. The underlying premise is that the space of human actions is characterized by a language; this new language has its own phonemes (primitives), its own morphemes (words/actions) and its own syntax, semantics and pragmatics. Although previous research has concentrated on finding primitives in very often isolated types of human action, the innovation here is the use of large amounts of human motion data in ecologically valid settings and in conjunction with modern data mining and grammatical induction techniques. To validate the HAL tool, we will apply it to assess atypical movement in Developmental Coordination Disorder (DCD) and Parkinson's disease (PD). Specifically, we propose to extract the DCD grammar and the PD grammar and compare them with the grammars from the control populations, investigating relationships between the corresponding grammars at the individual and workgroup levels. Our interdisciplinary team consists of a computational scientist, a behavioral scientist (motor development) , and a computational neuroscientist (motor control and learning). The proposed tool will extend the scope of behavioral sciences (grounding of language, imitation, and gesture-based social communication) and facilitate interdisciplinary research bringing together movement disorders specialists, behavioral scientists, physical or occupational therapists and computer scientists. Several NIH Institutes would benefit from the availability of such a tool, including NIA/NINDS, NIMH and NICHD. The ultimate goal is to better understand human action production and understanding, and to develop optimal diagnostic and intervention tools for populations with atypical movement patterns. The proposed tool will extend the scope of behavioral sciences (grounding of language, imitation, and gesture- based social communication) and facilitate interdisciplinary research bringing together movement disorders specialists, behavioral scientists, physical or occupational therapists and computer scientists. Several NIH Institutes would benefit from the availability of such a tool, including NIA/NINDS - for understanding motor decline in the elderly and neurological populations in single and group-based daily living activities, NIMH - for understanding stereotypical behaviors in populations affected with mental disorders, and NICHD - for understanding developmental aspects of cognitive motor behavior in children at school or home. The ultimate goal is to better understand human action production and understanding, and developing optimal diagnostic and intervention tools for populations with atypical movement patterns. [unreadable] [unreadable] [unreadable]