Human Odometry with a Two-Legged Hopping Gait: A Test of the Gait Symmetry Theory

Abstract

Biological odometry refers to the capacity for perceptually measuring distances traveled during locomotion. In the case of haptic odometry, information about distance traversed is generated from the movements of the legs, with coordinated leg motions (i.e., gait patterns) producing patterns of tissue deformation detectable by the haptic perceptual system. The gait symmetry theory of haptic odometry classifies gaits based upon the symmetry of muscle activation patterns. This classification identifies candidate higher-order variables of haptic odometry and provides a promising basis for understanding the associated patterns of tissue deformation detected by the haptic perceptual system. The theory successfully predicts biases (i.e., underestimations/overestimations) resulting from the manipulation of the gait patterns used in the outbound and return phases of homing tasks. We test gait symmetry theory by considering a previously unexamined key prediction. Two-legged hopping and walking have the same symmetry group classification, therefore, a homing task completed using any combination of two-legged hopping and walking as the outbound/return gaits should produce no systematic biases. Contrary to this prediction we observed systematic biases. We discuss the possibilities for modifying gait symmetry theory to account for our findings, and we present a new alternative theory based upon spatial reference frames.     

Equivalence of human odometry by walk and run is indifferent to self-selected speed

Humans and other animals can measure distances nonvisually by legged locomotion. Experiments typically employ an outbound measure (M) and an inbound report (R) phase. Previous research has found distance reproduction to be maximally accurate, when gait symmetry and speed of M and R are of like kind: Successful human odometry manifests at the level of the M-R system. In the present work, M was an experimenter-set distance produced by a blindfolded participant using a primary gait (walk, run). R was always by walk. Fast and slow versions of walk and run were adopted by participants, such that when M was fast R was slow, and vice versa. Distance was underestimated when M was slower than R and overestimated when M was faster than R. However, the pattern of participant-adopted velocities indicated that it was the instructions, not the speed as such, that yielded the pattern of results. The results are interpretable through a dynamical perspective and indicate speed is an imperfection parameter acting on the attractors of the M-R system.     

Symmetry axiom of Haken–Kelso–Bunz coordination dynamics revisited in the context of cognitive activity

We present an axiomatic derivation of a model proposed by Haken, Kelso, and Bunz (1985) that describes dynamical aspects of the rhythmic coordination between two limbs. Elaboration of this model has included a symmetry parameter that captures the coordination consequences of an inherent or imposed frequency difference between the limbs. We modified one of the axioms involved in the model derivation, a symmetry axiom, in order to incorporate a new symmetry parameter. This new parameter defines a shift between (a) the laboratory coordinate system, in which the behavior is observed, and (b) a second, postulated coordinate system. It is this second coordinate system, in which the relevant state dynamics is assumed to take place and in which the state dynamics evolves under the impact of an attractor. The state dynamics as described in the attractor coordinate system is then mapped by means of the new symmetry parameter to the laboratory coordinate system. We discuss analytically the bifurcation diagram of the model and determine main effects and interaction effects of manipulations related to the symmetry parameters and related to the mode of coordination (in-phase and anti-phase). The theoretical results are brought to bear on the challenging experimental observation that concurrent cognitive activity (counting, encoding, retrieving, sentence analysis) changes the location of the bimanual coordination attractor but not its strength. The theoretical results suggest that cognitive activity may have the effect it has because it shifts the attractor coordinate system relative to the laboratory coordinate system.     

Changes in Movement Variables Associated With Transient Overshoot of the Final Position

Transient overshoot (TO), which is assessed as the distance between the movement amplitude and the final position, was measured in a series of rapid, discrete elbow flexion movements performed under different distance and loading conditions by 7 participants. A positive relationship was found between kinematic variables (peak velocity, peak acceleration and deceleration, and the symmetry ratio) and the magnitude of TO, particularly in short movements performed against a light load. The relationships between TO and electromyographic (EMG) variables were low and mainly insignificant. Thus, TO contributes to the variability of rapid, discrete movements and therefore should be taken into account as an additional parameter in studies of the scaling of movement variables with movement mechanical conditions. TO could also represent a consequence of mechanical properties of the single-joint system rather than an independently programmed primary submovement.     

Changes in movement variables associated with transient overshoot of the final position

Transient overshoot (TO), which is assessed as the distance between the movement amplitude and the final position, was measured in a series of rapid, discrete elbow flexion movements performed under different distance and loading conditions by 7 participants. A positive relationship was found between kinematic variables (peak velocity, peak acceleration and deceleration, and the symmetry ratio) and the magnitude of TO, particularly in short movements performed against a light load. The relationships between TO and electromyographic (EMG) variables were low and mainly insignificant. Thus, TO contributes to the variability of rapid, discrete movements and therefore should be taken into account as an additional parameter in studies of the scaling of movement variables with movement mechanical conditions. TO could also represent a consequence of mechanical properties of the single-joint system rather than an independently programmed primary submovement.     

Primary and Secondary Caregiver Reports of Quality of Life in Pediatric Asthma: Are they Comparable?

This study aimed to compare primary and secondary caregiver QOL within families of children with asthma and determine the potential importance of including secondary caregiver QOL in clinical and research settings. Participants included 118 families of children with asthma that had primary and secondary caregivers. Families completed measures in a single research session. Caregivers reported on QOL, psychological functioning, and family burden; children completed a measure of QOL. Child lung function was determined from objective spirometry. Adherence to prescribed controller medication was measured for 6 weeks following the research visit. Primary caregiver QOL was significantly lower than secondary caregiver QOL (Mean overall QOL of 5.85 versus 6.17, p < .05). Better medication adherence was associated with higher primary caregiver QOL (ρ = .22, p = .02); secondary caregiver QOL, not primary caregiver QOL, was positively associated with child QOL (ρ = .20, p = .03). Families with discrepant QOL scores between caregivers (difference in scores of at least .50) were characterized by more family burden and primary caregiver psychological symptoms. Differences in QOL scores between caregivers may be a reflection of primary caregivers’ greater investment in daily asthma management. In families reporting low burden and few psychological difficulties in the primary caregiver, QOL assessments from either caregiver may may be informative and representative of how parents are adapting to child asthma. In families experiencing high levels of burden or more primary caregiver psychological difficulties, QOL reports from secondary caregivers may not be as clinically meaningful.     

"Taking" an Aerobics Class in the U.S. and "Entering" an Aerobics Class in Japan: Primary and Secondary Control in a Fitness Context

The study tested Weisz, Rothbaum, and Blackburn's (1984) hypothesis that "primary" control is emphasized in the United States and "secondary" control is emphasized in Japan. Aerobics participants in Japan and the United States completed surveys about their reasons for choosing classes, their attributions for mistakes in class, their behavioral responses to a difficult class, and what others in the class typically do. Some responses indicated that both groups use some secondary control. But Americans were more likely to report that they choose classes based on convenience and that they change moves in the class that are too difficult, a pattern that suggests primary control. Japanese were more likely to report that they choose classes based on their ability level, work harder when moves are too difficult, and attribute mistakes to a lack of fit between their own ability and the level of the class, a pattern that suggests more secondary control.     

Neural response to prosocial scenes relates to subsequent giving behavior in adolescents: A pilot study

Adolescence is characterized by extensive neural development and sensitivity to social context, both of which contribute to engaging in prosocial behaviors. Although it is established that prosocial behaviors are linked to positive outcomes in adulthood, little is known about the neural correlates of adolescents’ prosociality. Identifying whether the brain is differentially responsive to varying types of social input may be important for fostering prosocial behavior. We report pilot results using new stimuli and an ecologically valid donation paradigm indicating (1) brain regions typically recruited during socioemotional processing evinced differential activation when adolescents evaluated prosocial compared with social or noninteractive scenes (N = 20, ages 13–17 years, M_Age = 15.30 years), and (2) individual differences in temporoparietal junction recruitment when viewing others’ prosocial behaviors were related to adolescents’ own charitable giving. These novel findings have significant implications for understanding how the adolescent brain processes prosocial acts and for informing ways to support adolescents to engage in prosocial behaviors in their daily lives.     

Dynamics of postural control during bilateral stance – Effect of support area,visual input and age

The present study investigated the effect of support area, visual input and aging of the dynamics of postural control during bilateral stance. Fifteen young (22.1 ± 1.7 years) and fifteen older (68.3 ± 2.7 years) individuals completed four different 90 s bilateral stance trials: 1) shoulder wide feet distance with eyes open, 2) shoulder wide feet distance with eyes closed, 3) narrow feet distance with eyes open, and 4) narrow feet distance with eyes closed on a force plate form. The anterior (AP) and mediolateral (ML) center of pressure (COP) trajectories were calculated from the middle 60 s of the ground reaction forces and moments. Sample entropy (SaEn), correlation dimension (CoD), the largest Lyapunov exponent (LyE) and entropic half-life (ENT½) were calculated for the COP in both directions. In young individuals, a narrower support area resulted in a restricted movement solution space with lower SaEn, lower LyE and longer ENT½ in the executed motor control strategy, whereas it increased the CoD in the older individuals. During the eyes closed trials, SaEn, CoD and LyE increased and decreased ENT½ for both groups in the AP direction and increased SaEn and LyE in the ML direction for the older individuals alone. This indicates that aging is associated with direction- and task-dependent changes in the dynamics of the executed COP movements during postural stance tasks.     

Practice and Component Submovements: The Roles of Programming and Feedback in Rapid Aimed Limb Movements

An experiment is reported in which subjects (N = 30) practiced rapid aimed limb movements (wrist rotations), with either full visual feedback, no visual feedback, or delayed visual feedback. Previous research has indicated that, with practice, subjects increase the distance and duration of ballistic primary submovements and decrease the distance and duration of corrective secondary submovements. The design of the present experiment permitted the determination of whether these practice-related changes are results of improved programming of the primary submovement or of more efficient processing involved in the production of secondary submovements. The results suggest that improved programming occurs with practice. Furthermore, it appears that visual feedback is not solely responsible for the production of secondary submovements.     

Sit Down and Play: A Preventive Primary Care-Based Program to Enhance Parenting Practices

The primary care office offers an ideal setting to encourage parenting behaviors that promote early childhood development. We conducted a pilot study to establish feasibility and acceptability of Sit Down and Play (SDP), a brief primary care-based program to facilitate positive parenting behaviors through take-home play activities. A prospective 1-month study was conducted in an urban primary care clinic. SDP was administered to 30 caregivers of 6–12 month-old children while they waited for their well-child appointment. Caregivers completed baseline and 4-week follow-up surveys. Open-ended interview questions regarding acceptability and usefulness of SDP were administered and analyzed using content analysis. Parenting practices related to child development were measured with standardized measures and changes analyzed using paired t-test and linear mixed effects models. Most caregivers were mothers (90?%) and non-white (97?%); the majority of children received Medicaid (87?%). There were significant increases in parental reports of practices related to child development (p?<?0.001), including families who reported low incomes (i.e. <$25,000) and received a high-school education or less (p?=?0.001). Four main themes emerged from the open-ended interview data: (1) importance of play, (2) noticing a change in their child, (3) reinforcing existing positive parenting behaviors, and (4) satisfaction with the program. This preliminary study suggests that SDP is a feasible and potentially beneficial program that can be delivered during pediatric well-child visits. Further studies are needed to determine the effectiveness of SDP on parenting behaviors and developmental outcomes.     

The multiple baseline design across exemplars

Three variations of the multiple baseline design (MBD) have been identified in the behavioral literature: MBD across behaviors, subjects and situations. This analysis proposes an important variant of the MBD across behaviors, namely the MBD across exemplars. In this variant, two or more components (exemplars) of the behavior class form the baselines of the design. Thus, intervention is applied separately and sequentially to each target exemplar. The implicit rule of the MBD across exemplars can be seen in several published papers in the behavioral literature. The value of recognizing this variant of the MBD across behaviors is its usefulness as an alternative experimental intervention in clinical settings where the possibility of a convincing research design might not otherwise be seen.     

Systematic review of interruption and redirection procedures for autistic individuals

Interruption and redirection (IR) procedures involve systematically disrupting an undesirable behavior and prompting an individual to engage in an alternative behavior. These procedures have been frequently assessed for reducing repetitive behaviors for autistic individuals. The primary purpose of this review was to assess IR interventions to determine whether outcomes vary according to intervention characteristics, dependent variable types, design quality, or publication status. A secondary purpose was to assess the extent to which generalization and maintenance outcomes were measured and whether characteristics of these conditions were related to outcomes. IR interventions were moderately successful for reducing repetitive behaviors but less effective for improving corollary variables such as appropriate vocalizations and functional engagement. Generalization and maintenance outcomes, when measured, were poor. Results indicate the need for alternative or augmentative procedures that focus on engagement in meaningful interactions and activities.     

Measuring Callous Unemotional Behaviors in Early Childhood: Factor Structure and the Prediction of Stable Aggression in Middle Childhood

This study sought to replicate the results of our earlier study, which were published in this Journal (Willoughby et. al 2011), that used mother-reported items from the Achenbach System of Empirically Based Assessment to develop a screening measure of callous unemotional (CU) behaviors for use with preschool-aged children. We further sought to extend those results by exploring the predictive validity of the CU measure with aggression trajectories in early-/mid- childhood. The current study involved secondary data analysis of the NICHD Study of Early Childhood and Youth Development (NICHD-SECCYD) dataset. Factor analyses included N?=?1,176 children who participated in the age 3 year assessment of the NICHD-SECCYD. Predictive models included N?=?1,081 children for whom four of the six possible teacher ratings of aggressive behavior were available from annual assessments spanning 1st–6th grades. Consistent with prior work, a three-factor confirmatory factor model, which differentiated CU from oppositional defiant (ODD) and attention deficit/hyperactive-impulsive (ADHD) behaviors, provided the best fit to the data. Among children with disorganized attachment status, the combination of high levels of mother-rated ODD behaviors and CU behaviors, was predictive of stable elevated levels of teacher-rated aggression from 1st–6th grade (predicted probability?=?0.38, compared with a base rate of 0.07). These results demonstrate that CU behaviors can be reliably measured by parent report in young children and are dissociable from more commonly assessed dimensions of disruptive behavior. Three-year-old children who exhibit elevated levels of ODD and CU behaviors, and who have disorganized attachments, are at increased risk for exhibiting elevated levels of aggression across middle childhood. Results are discussed from the perspective of early assessment and intervention.     

APPLICATION OF A SOCIAL SKILLS TRAINING PROGRAM IN THE MODIFICATION OF INTERPERSONAL DEFICITS AMONG RETARDED ADULTS: A CLINICAL REPLICATION

Six mentally retarded adults, equally divided into two treatment groups, were provided with individualized social skills training programs. Treatment, evaluated via a multiple-baseline design strategy, was sequentially and cumulatively applied across target behaviors over a four-week intervention period. Behavioral observation probes and social validation measures served as the primary dependent variables. Results indicated that (a) treatment was effective for virtually all behaviors across all subjects, (b) improvements occurred for both training and generalization scenes, and (c) behavioral performance was maintained one month following the termination of treatment.     

多阶段混合增长模型的方法及研究现状

多阶段混合增长模型(PGMM)可对发展过程中的阶段性及群体异质性特征进行分析,在能力发展、行为发展及干预、临床心理等研究领域应用广泛。PGMM可在结构方程模型和随机系数模型框架下定义,通常使用基于EM算法的极大似然估计和基于马尔科夫链蒙特卡洛模拟的贝叶斯推断两种方法进行参数估计。样本量、测量时间点数、潜在类别距离等因素对模型及参数估计有显著影响。未来应加强PGMM与其它增长模型的比较研究;在相同或不同的模型框架下研究数据特征、类别属性等对参数估计方法的影响。     

Adult Bullying and Primary and Secondary Psychopathic Traits: Insights from a Community Sample

This study aimed to: (a) comprehend the relationship between primary and secondary psychopathy variants and bullying behaviors in adults; (b) to test for mediation effects of the experiences of victimization in strengthening the bonds between bullying and psychopathy; and (c) to explore how far gender and psychopathic variants predict bullying. Results showed that psychopathy (both primary and secondary) and gender (male) significantly predicted bullying perpetrator behaviors. These same predictors were also significant in explaining total involvement with bullying; primary psychopathy displayed, however, better explanatory power. Being a victim of bullying also mediated the relationship between psychopathic variants and bullying perpetrating. The magnitude of the correlations between bullying and both psychopathic variants detected in this study were bigger than the average reported in studies with children and adolescents, which could inform about greater severity of these behaviors in adult life. Specifically, findings from regression analyses suggest that components of cold-blooded psychopathy could be driving the engagement of this sample with aggressive behaviors. Implications of these findings, along with limitations and directions for further research are discussed.     

小学儿童尊重行为与人格、班级环境的关系

以356名北京市两所小学三、四、五年级的小学儿童为被试,采用自编的小学儿童尊重行为问卷、国内修订的学生人格五因素问卷和班级环境问卷,考察小学儿童尊重行为的特点,并探讨人格和班级环境对尊重行为的影响.结果发现:(1)小学儿童的总体尊重行为和其中的理解欣赏具有显著的性别差异和城郊差异;(2)尊重行为与人格各维度具有显著的相关,与班级环境中除了竞争气氛之外的其他四个维度都有显著相关;(3)人格的宜人性、谨慎性、情绪性和开放性以及班级环境中的同学关系能够显著预测尊重行为,人格和班级环境的不同维度对于尊重行为不同维度具有不同的预测力;(4)小学儿童的班级环境可以归为三种类型:积极型、一般型和问题型,不同类型的班级环境在尊重行为上具有显著差异.     

Evaluation of Lower Limb Neuromuscular System Observability and Estimability of Muscle Activity

Abstract

In this work, we describe a method for estimating the muscle activity without drawing any assumptions regarding optimality principles in human motor control strategies; further, the method does not require any neural circuitry modeling which limits the neurophysiological terms and estimability of the method. We introduce the concept of system observability, which can reconstruct states from outputs and their derivatives based on system dynamics. Based on neuromuscular system observability, we estimate the muscle activity from joint torques and kinematics of multiple locomotive gaits, while considering the unknown neural inputs as system disturbances. Moreover, to quantify the robustness of the method, the degree of observability and parameter sensitivity are evaluated. Finally, the neurophysiological implications and generality of the method are addressed.