International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / A fiber optic event timing system was developed for the High Speed Test Track at Holloman Air Force Base, Alamogordo, NM. The system uses fiber optic sensors to detect the passage of rocket sleds by different stations along the track. The sensors are connected by fiber optic cables to an electronics package that records the event time to a resolution of 100 nanoseconds. By use of a GPS receiver as the timebase, the event time is stored to an absolute accuracy of 300 nanoseconds. Custom VMEbus boards were developed for the event timing function, and these boards are controlled by a programmable high speed sequencer, which allows for complicated control functions. Each board has 4 electro-optic channels, and multiple boards can be used in a VMEbus card cage controlled by a single board computer. The system has been tested in a series of missions at the Test Track.

The main aim of this thesis is to understand the extent to which intraspecific variation in developmental event timing might provide the raw material from which heterochronies may originate. To this end I studied the timing of a suite of both morphological and physiological events in the embryonic development of Radix balthica, a species of aquatic snail known to exhibit event timing variation during the embryonic period (Tills et al. 2010; Rundle et al. 2011) and that sits within an evolutionary clade, in which extensive heterochrony has been documented (Smirthwaite et al. 2007). I found that variation in embryonic developmental event timing within R. balthica is pervasive (Chapters 2 - 5) and distributed primarily at low (inter-individual and egg mass), rather than high (population) biological levels (Chapter 3). This variation also appears to have a genetic basis (Chapter 2) and to be heritable (Chapters 4 and 5). Examination of the development of function in the cardiovascular (CV) system in Chapter 5 also revealed extensive variation, including differences between egg masses in the timing of aspects of this development, and differences between populations in the rates of change in heart rate during different phases of ontogeny. Variation in CV development also had effects on life history, which suggest that altered embryonic development might have implications for Darwinian fitness (Chapter 5). This thesis demonstrates that intraspecific variation in developmental event timing represents a fundamental link between ontogeny and phylogeny and that study of altered timing at the inter-individual level provides the opportunity to address questions concerning its evolvability and implications.

Recent investigations suggest that rhythmic movements rely on two distinct timing systems: event and emergent timing. Event timing is based on an explicit internal representation of the temporal interval marked by clear perceptual detectible events whereas emergent timing is derived from the dynamics of smooth and continuous movements. However, crucial aspects of the distinction between these mechanisms remain unclear. This thesis investigates the role of expectancy and skill in the internal representation of time in event timing and emergent timing. Chapter 1 introduces the theoretical framework that supports the differentiation between event and emergent timing mechanisms and presents the hypotheses that were tested. Chapter 2 describes a series of five experiments that investigated the role of expectancy through examining the effect of a single unexpected perturbation of feedback content (e.g. pitch, timbre, intensity) on timing of finger tapping. Chapter 3 expands this question by investigating the effect of unexpected auditory perturbations on two types of timed movements: event and emergent timing. The role of expertise and training on motor timing is the subject of discussion of Chapters 4 to 6 where a total of 4 experiments tested the effect of expertise and music training on accuracy of finger tapping and circle drawing tasks. More specifically, Chapter 4 compares accuracy levels of experts in movement-based activities (music and sports) with non experts, whereas Chapters 5 and 6 focus on the effect of music training on event and emergent timing in students of 10 to 14 years of age. Finally, Chapter 7 reviews and discusses the main findings of this body of work with respect to current theories of timing and movement. Foremost, these data challenge current models of human movements controlled by event and emergent timing mechanisms demonstrating that expectancy and training are crucial in determining the timing strategy and the type of expectancy mechanisms adopted to perform distinct rhythmic movements / Estudos recentes sugerem que movimentos rítmicos dependem de dois sistemas distintos para controle do tempo, chamados tempo emergente e discreto. Sugere-se que tempo discreto baseia-se em uma representação interna do tempo intervalar que é marcada por eventos perceptuais evidentes, enquanto tempo emergente origina-se da própria dinâmica dos movimentos contínuous. No entanto, aspectos cruciais da diferença entre esses mecanismos ainda necessitam ser examinados. Esta tese investiga o papel de expectativas e treino no controle temporal de movimentos rítmicos contínuous e discretos. Capítulo 1 introduz as bases teóricas que subsidiam as hipóteses testadas no presente trabalho. Capítulo 2 descreve uma série de cinco experimentos que investigam a importância da retroalimentação auditiva e dos mecanismos de expectativa, e assim examina o efeito de uma perturbação inesperada e transitória no conteúdo do feedback (e.x. altura, timbre, intensidade) na precisão temporal de movimentos rítmicos discretos (i.e. finger tapping). Capítulo 3 expande essa investigação e analisa o efeito de perturbações inesperadas da retroalimentação auditivo em tarefas de movimentos contínuos, como desenhar círculos repetidamente. O papel do treinamento para o controle temporal é foco de discussão nos Capítulos 4 a 6, onde se descrevem um total de quatro experimentos que testam o efeito de expertise e treino na precisão de movimentos em tarefas de finger tapping e desenho de círculos. Mais especificamente, Capítulo 4 compara a performance de músicos e atletas com participantes sem nenhum treinamento nestas áreas a fim de examinar o papel do treinamento no controle motor, enquanto os Capítulo 5 e 6 focam no efeito do treino em música no controle temporal de movimentos rítmicos discretos e contínuous em estudantes de 10 a 14 anos de idade. Capítulo 7 revisa e conclui as discussões propostas com base nos principais resultados descritos neste trabalho. Em suma, os resultados apresentam novas e relevantes informações a respeito da importância de expectativas e do treinamento no controle temporal de movimentos rítmicos, cujas implicações podem contribuir significativamente para áreas relacionadas à pedagogia e reabilitação motora. Além disso, esta tese apresenta novas informações que ampliam modelos atuais sobre os mecanismos envolvidos no controle temporal de movimentos rítmicos demonstrando a importância do papel de expectativas, retroalimentação auditiva e do treinamento para determinar os diferentes mecanismos de expectativa adotados pelo sistema nervoso na execução de movimentos rítmicos

Recent investigations suggest that rhythmic movements rely on two distinct timing systems: event and emergent timing. Event timing is based on an explicit internal representation of the temporal interval marked by clear perceptual detectible events whereas emergent timing is derived from the dynamics of smooth and continuous movements. However, crucial aspects of the distinction between these mechanisms remain unclear. This thesis investigates the role of expectancy and skill in the internal representation of time in event timing and emergent timing. Chapter 1 introduces the theoretical framework that supports the differentiation between event and emergent timing mechanisms and presents the hypotheses that were tested. Chapter 2 describes a series of five experiments that investigated the role of expectancy through examining the effect of a single unexpected perturbation of feedback content (e.g. pitch, timbre, intensity) on timing of finger tapping. Chapter 3 expands this question by investigating the effect of unexpected auditory perturbations on two types of timed movements: event and emergent timing. The role of expertise and training on motor timing is the subject of discussion of Chapters 4 to 6 where a total of 4 experiments tested the effect of expertise and music training on accuracy of finger tapping and circle drawing tasks. More specifically, Chapter 4 compares accuracy levels of experts in movement-based activities (music and sports) with non experts, whereas Chapters 5 and 6 focus on the effect of music training on event and emergent timing in students of 10 to 14 years of age. Finally, Chapter 7 reviews and discusses the main findings of this body of work with respect to current theories of timing and movement. Foremost, these data challenge current models of human movements controlled by event and emergent timing mechanisms demonstrating that expectancy and training are crucial in determining the timing strategy and the type of expectancy mechanisms adopted to perform distinct rhythmic movements / Estudos recentes sugerem que movimentos rítmicos dependem de dois sistemas distintos para controle do tempo, chamados tempo emergente e discreto. Sugere-se que tempo discreto baseia-se em uma representação interna do tempo intervalar que é marcada por eventos perceptuais evidentes, enquanto tempo emergente origina-se da própria dinâmica dos movimentos contínuous. No entanto, aspectos cruciais da diferença entre esses mecanismos ainda necessitam ser examinados. Esta tese investiga o papel de expectativas e treino no controle temporal de movimentos rítmicos contínuous e discretos. Capítulo 1 introduz as bases teóricas que subsidiam as hipóteses testadas no presente trabalho. Capítulo 2 descreve uma série de cinco experimentos que investigam a importância da retroalimentação auditiva e dos mecanismos de expectativa, e assim examina o efeito de uma perturbação inesperada e transitória no conteúdo do feedback (e.x. altura, timbre, intensidade) na precisão temporal de movimentos rítmicos discretos (i.e. finger tapping). Capítulo 3 expande essa investigação e analisa o efeito de perturbações inesperadas da retroalimentação auditivo em tarefas de movimentos contínuos, como desenhar círculos repetidamente. O papel do treinamento para o controle temporal é foco de discussão nos Capítulos 4 a 6, onde se descrevem um total de quatro experimentos que testam o efeito de expertise e treino na precisão de movimentos em tarefas de finger tapping e desenho de círculos. Mais especificamente, Capítulo 4 compara a performance de músicos e atletas com participantes sem nenhum treinamento nestas áreas a fim de examinar o papel do treinamento no controle motor, enquanto os Capítulo 5 e 6 focam no efeito do treino em música no controle temporal de movimentos rítmicos discretos e contínuous em estudantes de 10 a 14 anos de idade. Capítulo 7 revisa e conclui as discussões propostas com base nos principais resultados descritos neste trabalho. Em suma, os resultados apresentam novas e relevantes informações a respeito da importância de expectativas e do treinamento no controle temporal de movimentos rítmicos, cujas implicações podem contribuir significativamente para áreas relacionadas à pedagogia e reabilitação motora. Além disso, esta tese apresenta novas informações que ampliam modelos atuais sobre os mecanismos envolvidos no controle temporal de movimentos rítmicos demonstrando a importância do papel de expectativas, retroalimentação auditiva e do treinamento para determinar os diferentes mecanismos de expectativa adotados pelo sistema nervoso na execução de movimentos rítmicos