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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Medidas de EEG evocadas por tarefas de simulação de ação relativas aos treinamentos de indivíduos com habilidades percepto-motoras distintas (bailarinas x voleibolistas)

Daronch, Cláudia January 2012 (has links)
Executantes habilidosos desenvolvem uma capacidade de perceber e processar uma vasta quantidade de informações com velocidade e precisão, bem como o de realizar ajustes eficientes quando necessário (Schmidt e Wrisberg 2001). Corticalmente, para obter esse controle mais refinado, a integração sensoriomotora é fundamental. Essa integração consiste no contínuo processamento, pelo sistema motor, das aferências sensoriais que preparam para o ato motor e melhoram a execução de atividades de controle motor fino (Minc et al., 2010). Atividades físicas que diferem exatamente em relação a como seus praticantes necessitam processar as informações sensoriais para gerar o movimento, devem resultar em integrações sensoriomotoras distintas. Este estudo tem como objetivo analisar a atividade eletroencefálica de indivíduos com habilidades percepto-motoras distintas (indivíduos altamente habilidosos com treinamento em dança/TD e treinamento em vôlei/TV), evocados por tarefas de simulação de ação. A amostra do presente estudo foi intencional e composta por 14 participantes destros, cada grupo foi constituído por 07 mulheres com idade entre 18 anos e 29 anos. Através de EEG, foram extraídos os parâmetros de média de energia (processamento cortical ao longo do tempo), amplitude (número de elementos neuronais envolvidos na tarefa) e frequência (ritmo oscilatório predominante) na banda alfa e gama do sinal cerebral nos pontos C3, C4, Cz (córtex motor primário), F3 (área motora suplementar esquerda), F7 (córtex pré-motor esquerdo), P3, P4 e Pz (córtex parietal), evocados por tarefas envolvendo a observação e imaginação de gestos específicos dos dois treinamentos e gestos considerados como neutros. Os principais resultados encontrados forneceram evidências de que o grupo TD apresentou, nas tarefas de dança, um maior processamento cortical ao longo do tempo nos pontos referentes ao córtex motor primário (Minc et al., 2010), córtex pré-motor (Freund e Hummelsheim, 1984) e área motora suplementar (Serrien et al.,2002) esquerdos; maior número de elementos neuronais envolvidos na tarefa no ponto referente ao córtex motor primário esquerdo; diferenças na principal componente da frequência no ritmo alfa no córtex motor primário esquerdo; e diferenças na principal componente da frequência no ritmo gama no córtex motor primário direito. Nas tarefas referentes ao treinamento em vôlei, o grupo TV apresentou menor processamento ao longo do tempo nos pontos parietal (Wolpert et al., 1998); menor número de elementos neuronais envolvidos na tarefa nos pontos referentes aos córtices motor primário e pré-motor esquerdos e diferença na principal componente da frequência no ritmo gama no córtex motor primário esquerdo. Nas tarefas consideradas como neutras foram encontradas diferenças entre os grupos no córtex motor primário direito no ritmo alfa e no córtex parietal direito no ritmo gama. Os resultados encontrados no presente estudo nos parâmetros que representam o processamento cortical, que refletem o número de elementos neuronais envolvidos na tarefa e que representam o ritmo oscilatório predominante demonstraram claramente que as regiões corticais envolvidas na integração sensoriomotora apresentaram diferenças na forma como os dois grupos processaram a informação sensorial e prepararam o gesto motor. Tomados em conjunto, esses resultados demonstram que cada grupo apresentou um padrão constante de processamento sensoriomotor, independente da tarefa. Essas evidências nos permitem concluir que indivíduos com diferentes habilidades percepto-motoras apresentam integrações sensoriomotoras distintas. / Skilled performers develop an ability to perceive and process a vast amount of information with speed and accuracy, as well as to perform efficient adjustments when necessary (Schmidt and Wrisberg 2001). Cortically to achieve this finer control, sensorimotor integration is the key. This integration consists in continuous processing, by the motor system, the sensory afferents that prepare for the motor act and improve the performance of activities for fine motor control (Minc et al., 2010). Physical activities that differ over exactly how its practitioners need to process sensory information to generate movement should result in distinct sensorimotor integration. This study aims to analyze the electroencephalography activity of individuals with perceptual-motor skills (highly skilled individuals with training in dance/TD and training in volleyball/TV) evoked by action simulation tasks. The study sample was intentional and composed of 14 right-handed participants; each group consisted of 07 women aged between 18 and 29 years. Through EEG were extracted parameters mean energy (cortical processing over time), amplitude (number of neural elements involved in the task) and frequency (oscillating rhythm predominant) in alpha and gamma bands in the brain signal points C3, C4, Cz (primary motor cortex), F3 (left supplementary motor area), F7 (left premotor cortex), P3, P4 and Pz (parietal cortex), evoked by tasks involving observation and imagination of specific gestures of both training and gestures considered neutral. The main results provided evidence that the TD group presented the tasks of dance, a higher cortical processing over time in points for the primary motor cortex (Minc et al., 2010), left premotor cortex (Freund and Hummelsheim, 1984) and left supplementary motor area (Serrien et al. 2002); greater number of neural elements involved in the task at point for the left primary motor cortex; differences in the main frequency component of the alpha rhythm in the left primary motor cortex , and differences in the main component of the frequency gamma in the right primary motor cortex. In tasks relating to training volleyball, VT group showed lower processing over time at parietal points (Wolpert et al. 1998); smaller number of neural elements involved in the task at points related to left primary motor cortex and left premotor and main component difference in the frequency gamma in the left primary motor cortex. In the tasks considered neutral differences were found between groups in the right primary motor cortex in the alpha rhythm and in the right parietal cortex in the gamma rhythm. The results found in this study at the parameters that represent the cortical processing, that reflect the number of neuronal elements involved in the task and which represent the predominant rhythm oscillatory clearly demonstrated that cortical regions involved in sensorimotor integration showed differences in how the two groups processed sensory information and prepared the gesture motor. Taken together, these results demonstrate that each group had a consistent pattern of sensorimotor processing, regardless of the task. This evidence allows us to conclude that individuals with different perceptual-motor skills have distinct sensorimotor integration.
92

Medidas de EEG evocadas por tarefas de simulação de ação relativas aos treinamentos de indivíduos com habilidades percepto-motoras distintas (bailarinas x voleibolistas)

Daronch, Cláudia January 2012 (has links)
Executantes habilidosos desenvolvem uma capacidade de perceber e processar uma vasta quantidade de informações com velocidade e precisão, bem como o de realizar ajustes eficientes quando necessário (Schmidt e Wrisberg 2001). Corticalmente, para obter esse controle mais refinado, a integração sensoriomotora é fundamental. Essa integração consiste no contínuo processamento, pelo sistema motor, das aferências sensoriais que preparam para o ato motor e melhoram a execução de atividades de controle motor fino (Minc et al., 2010). Atividades físicas que diferem exatamente em relação a como seus praticantes necessitam processar as informações sensoriais para gerar o movimento, devem resultar em integrações sensoriomotoras distintas. Este estudo tem como objetivo analisar a atividade eletroencefálica de indivíduos com habilidades percepto-motoras distintas (indivíduos altamente habilidosos com treinamento em dança/TD e treinamento em vôlei/TV), evocados por tarefas de simulação de ação. A amostra do presente estudo foi intencional e composta por 14 participantes destros, cada grupo foi constituído por 07 mulheres com idade entre 18 anos e 29 anos. Através de EEG, foram extraídos os parâmetros de média de energia (processamento cortical ao longo do tempo), amplitude (número de elementos neuronais envolvidos na tarefa) e frequência (ritmo oscilatório predominante) na banda alfa e gama do sinal cerebral nos pontos C3, C4, Cz (córtex motor primário), F3 (área motora suplementar esquerda), F7 (córtex pré-motor esquerdo), P3, P4 e Pz (córtex parietal), evocados por tarefas envolvendo a observação e imaginação de gestos específicos dos dois treinamentos e gestos considerados como neutros. Os principais resultados encontrados forneceram evidências de que o grupo TD apresentou, nas tarefas de dança, um maior processamento cortical ao longo do tempo nos pontos referentes ao córtex motor primário (Minc et al., 2010), córtex pré-motor (Freund e Hummelsheim, 1984) e área motora suplementar (Serrien et al.,2002) esquerdos; maior número de elementos neuronais envolvidos na tarefa no ponto referente ao córtex motor primário esquerdo; diferenças na principal componente da frequência no ritmo alfa no córtex motor primário esquerdo; e diferenças na principal componente da frequência no ritmo gama no córtex motor primário direito. Nas tarefas referentes ao treinamento em vôlei, o grupo TV apresentou menor processamento ao longo do tempo nos pontos parietal (Wolpert et al., 1998); menor número de elementos neuronais envolvidos na tarefa nos pontos referentes aos córtices motor primário e pré-motor esquerdos e diferença na principal componente da frequência no ritmo gama no córtex motor primário esquerdo. Nas tarefas consideradas como neutras foram encontradas diferenças entre os grupos no córtex motor primário direito no ritmo alfa e no córtex parietal direito no ritmo gama. Os resultados encontrados no presente estudo nos parâmetros que representam o processamento cortical, que refletem o número de elementos neuronais envolvidos na tarefa e que representam o ritmo oscilatório predominante demonstraram claramente que as regiões corticais envolvidas na integração sensoriomotora apresentaram diferenças na forma como os dois grupos processaram a informação sensorial e prepararam o gesto motor. Tomados em conjunto, esses resultados demonstram que cada grupo apresentou um padrão constante de processamento sensoriomotor, independente da tarefa. Essas evidências nos permitem concluir que indivíduos com diferentes habilidades percepto-motoras apresentam integrações sensoriomotoras distintas. / Skilled performers develop an ability to perceive and process a vast amount of information with speed and accuracy, as well as to perform efficient adjustments when necessary (Schmidt and Wrisberg 2001). Cortically to achieve this finer control, sensorimotor integration is the key. This integration consists in continuous processing, by the motor system, the sensory afferents that prepare for the motor act and improve the performance of activities for fine motor control (Minc et al., 2010). Physical activities that differ over exactly how its practitioners need to process sensory information to generate movement should result in distinct sensorimotor integration. This study aims to analyze the electroencephalography activity of individuals with perceptual-motor skills (highly skilled individuals with training in dance/TD and training in volleyball/TV) evoked by action simulation tasks. The study sample was intentional and composed of 14 right-handed participants; each group consisted of 07 women aged between 18 and 29 years. Through EEG were extracted parameters mean energy (cortical processing over time), amplitude (number of neural elements involved in the task) and frequency (oscillating rhythm predominant) in alpha and gamma bands in the brain signal points C3, C4, Cz (primary motor cortex), F3 (left supplementary motor area), F7 (left premotor cortex), P3, P4 and Pz (parietal cortex), evoked by tasks involving observation and imagination of specific gestures of both training and gestures considered neutral. The main results provided evidence that the TD group presented the tasks of dance, a higher cortical processing over time in points for the primary motor cortex (Minc et al., 2010), left premotor cortex (Freund and Hummelsheim, 1984) and left supplementary motor area (Serrien et al. 2002); greater number of neural elements involved in the task at point for the left primary motor cortex; differences in the main frequency component of the alpha rhythm in the left primary motor cortex , and differences in the main component of the frequency gamma in the right primary motor cortex. In tasks relating to training volleyball, VT group showed lower processing over time at parietal points (Wolpert et al. 1998); smaller number of neural elements involved in the task at points related to left primary motor cortex and left premotor and main component difference in the frequency gamma in the left primary motor cortex. In the tasks considered neutral differences were found between groups in the right primary motor cortex in the alpha rhythm and in the right parietal cortex in the gamma rhythm. The results found in this study at the parameters that represent the cortical processing, that reflect the number of neuronal elements involved in the task and which represent the predominant rhythm oscillatory clearly demonstrated that cortical regions involved in sensorimotor integration showed differences in how the two groups processed sensory information and prepared the gesture motor. Taken together, these results demonstrate that each group had a consistent pattern of sensorimotor processing, regardless of the task. This evidence allows us to conclude that individuals with different perceptual-motor skills have distinct sensorimotor integration.
93

Medidas de EEG evocadas por tarefas de simulação de ação relativas aos treinamentos de indivíduos com habilidades percepto-motoras distintas (bailarinas x voleibolistas)

Daronch, Cláudia January 2012 (has links)
Executantes habilidosos desenvolvem uma capacidade de perceber e processar uma vasta quantidade de informações com velocidade e precisão, bem como o de realizar ajustes eficientes quando necessário (Schmidt e Wrisberg 2001). Corticalmente, para obter esse controle mais refinado, a integração sensoriomotora é fundamental. Essa integração consiste no contínuo processamento, pelo sistema motor, das aferências sensoriais que preparam para o ato motor e melhoram a execução de atividades de controle motor fino (Minc et al., 2010). Atividades físicas que diferem exatamente em relação a como seus praticantes necessitam processar as informações sensoriais para gerar o movimento, devem resultar em integrações sensoriomotoras distintas. Este estudo tem como objetivo analisar a atividade eletroencefálica de indivíduos com habilidades percepto-motoras distintas (indivíduos altamente habilidosos com treinamento em dança/TD e treinamento em vôlei/TV), evocados por tarefas de simulação de ação. A amostra do presente estudo foi intencional e composta por 14 participantes destros, cada grupo foi constituído por 07 mulheres com idade entre 18 anos e 29 anos. Através de EEG, foram extraídos os parâmetros de média de energia (processamento cortical ao longo do tempo), amplitude (número de elementos neuronais envolvidos na tarefa) e frequência (ritmo oscilatório predominante) na banda alfa e gama do sinal cerebral nos pontos C3, C4, Cz (córtex motor primário), F3 (área motora suplementar esquerda), F7 (córtex pré-motor esquerdo), P3, P4 e Pz (córtex parietal), evocados por tarefas envolvendo a observação e imaginação de gestos específicos dos dois treinamentos e gestos considerados como neutros. Os principais resultados encontrados forneceram evidências de que o grupo TD apresentou, nas tarefas de dança, um maior processamento cortical ao longo do tempo nos pontos referentes ao córtex motor primário (Minc et al., 2010), córtex pré-motor (Freund e Hummelsheim, 1984) e área motora suplementar (Serrien et al.,2002) esquerdos; maior número de elementos neuronais envolvidos na tarefa no ponto referente ao córtex motor primário esquerdo; diferenças na principal componente da frequência no ritmo alfa no córtex motor primário esquerdo; e diferenças na principal componente da frequência no ritmo gama no córtex motor primário direito. Nas tarefas referentes ao treinamento em vôlei, o grupo TV apresentou menor processamento ao longo do tempo nos pontos parietal (Wolpert et al., 1998); menor número de elementos neuronais envolvidos na tarefa nos pontos referentes aos córtices motor primário e pré-motor esquerdos e diferença na principal componente da frequência no ritmo gama no córtex motor primário esquerdo. Nas tarefas consideradas como neutras foram encontradas diferenças entre os grupos no córtex motor primário direito no ritmo alfa e no córtex parietal direito no ritmo gama. Os resultados encontrados no presente estudo nos parâmetros que representam o processamento cortical, que refletem o número de elementos neuronais envolvidos na tarefa e que representam o ritmo oscilatório predominante demonstraram claramente que as regiões corticais envolvidas na integração sensoriomotora apresentaram diferenças na forma como os dois grupos processaram a informação sensorial e prepararam o gesto motor. Tomados em conjunto, esses resultados demonstram que cada grupo apresentou um padrão constante de processamento sensoriomotor, independente da tarefa. Essas evidências nos permitem concluir que indivíduos com diferentes habilidades percepto-motoras apresentam integrações sensoriomotoras distintas. / Skilled performers develop an ability to perceive and process a vast amount of information with speed and accuracy, as well as to perform efficient adjustments when necessary (Schmidt and Wrisberg 2001). Cortically to achieve this finer control, sensorimotor integration is the key. This integration consists in continuous processing, by the motor system, the sensory afferents that prepare for the motor act and improve the performance of activities for fine motor control (Minc et al., 2010). Physical activities that differ over exactly how its practitioners need to process sensory information to generate movement should result in distinct sensorimotor integration. This study aims to analyze the electroencephalography activity of individuals with perceptual-motor skills (highly skilled individuals with training in dance/TD and training in volleyball/TV) evoked by action simulation tasks. The study sample was intentional and composed of 14 right-handed participants; each group consisted of 07 women aged between 18 and 29 years. Through EEG were extracted parameters mean energy (cortical processing over time), amplitude (number of neural elements involved in the task) and frequency (oscillating rhythm predominant) in alpha and gamma bands in the brain signal points C3, C4, Cz (primary motor cortex), F3 (left supplementary motor area), F7 (left premotor cortex), P3, P4 and Pz (parietal cortex), evoked by tasks involving observation and imagination of specific gestures of both training and gestures considered neutral. The main results provided evidence that the TD group presented the tasks of dance, a higher cortical processing over time in points for the primary motor cortex (Minc et al., 2010), left premotor cortex (Freund and Hummelsheim, 1984) and left supplementary motor area (Serrien et al. 2002); greater number of neural elements involved in the task at point for the left primary motor cortex; differences in the main frequency component of the alpha rhythm in the left primary motor cortex , and differences in the main component of the frequency gamma in the right primary motor cortex. In tasks relating to training volleyball, VT group showed lower processing over time at parietal points (Wolpert et al. 1998); smaller number of neural elements involved in the task at points related to left primary motor cortex and left premotor and main component difference in the frequency gamma in the left primary motor cortex. In the tasks considered neutral differences were found between groups in the right primary motor cortex in the alpha rhythm and in the right parietal cortex in the gamma rhythm. The results found in this study at the parameters that represent the cortical processing, that reflect the number of neuronal elements involved in the task and which represent the predominant rhythm oscillatory clearly demonstrated that cortical regions involved in sensorimotor integration showed differences in how the two groups processed sensory information and prepared the gesture motor. Taken together, these results demonstrate that each group had a consistent pattern of sensorimotor processing, regardless of the task. This evidence allows us to conclude that individuals with different perceptual-motor skills have distinct sensorimotor integration.
94

The Virtual Self : Sensory-Motor Plasticity of Virtual Body-Ownership

Fasthén, Patrick January 2014 (has links)
The distinction between the sense of body-ownership and the sense of agency has attracted considerable empirical and theoretical interest lately. However, the respective contributions of multisensory and sensorimotor integration to these two varieties of body experience are still the subject of ongoing research. In this study, I examine the various methodological problems encountered in the empirical study of body-ownership and agency with the use of novel immersive virtual environment technology to investigate the interplay between sensory and motor information. More specifically, the focus is on testing the relative contributions and possible interactions of visual-tactile and visual-motor contingencies implemented under the same experimental protocol. The effect of this is supported by physiological measurements obtained from skin conductance responses and heart rate. The findings outline a relatively simple method for identifying the necessary and sufficient conditions for the experience of body-ownership and agency, as studied with immersive virtual environment technology.
95

Speech motor development of Afrikaans speaking children aged four to seven years

Grobler, Isabella Johanna 11 January 2007 (has links)
The limited amount of normative information regarding speech motor development in the clinically important age range four to seven years served as motivation for this study. The main aim of the study was to collect normative information regarding sensorimotor speech control skills of pre-school children. The method of the study was designed and the results interpreted within the framework of the four-level model of speech production of Van der Merwe (1997). Basic qualitative and quantitative data were gathered for a variety of aspects of speech motor development in Afrikaans-speaking children aged 4;0 to 6;7 years in the following areas: 1) non-speech oral movements, 2) non-speech diadochokinesis, 3) speech diadochokinesis, 4) cluster production, 5) word syllable structure in spontaneous speech, 6) acoustic data regarding first-vowel duration and variability of first-vowel duration in repeated utterances of the same word, 7) acoustic voice onset time data, 8) acoustic data regarding first-syllable duration in words of increasing length. Results indicated that associated movements and accuracy errors occurred in some non-speech oral movement and non-speech diadochokinesis tasks. Normative, diadochokinetic rate data were gathered. Perceptual analysis indicated difficulty with glottal and three-place diadochokinesis tasks. Subjects produced 84% of initial clusters in isolation correctly and 79% of final clusters. Schwa-vowel insertions occurred in clusters in isolation, but not in spontaneously produced words. Subjects produced 163 different word syllable structures in spontaneous speech, with 18 structures occurring in all subjects’ data. Six-year-olds generally displayed the shortest first-vowel duration. Individual, non-age related trends occurred for variability of first-vowel duration. Mean voice onset times in voiced stop contexts ranged from -97ms to +12ms, with overall instances of mean voicing lead occurring in 27% of the four-year olds’ productions, 4% of the five-year-olds’ productions and 80% of the six-year-olds’ productions. Mean voice onset times in voiceless stop contexts ranged from +11ms to +37ms. Subjects adapted first-syllable duration to word length by decreasing it as the word length increased. Results indicated that a wide range of normal speech motor performance is possible for children this age, and that individuals can display different performance levels for different speech parameters. This emphasizes the complexity of speech motor development and the need to assess a variety of speech motor parameters. It is essential that quantitative (objective) analysis of children’s speech motor performance be supplemented with qualitative (descriptive) analysis. The study contributed knowledge to the understanding of certain aspects of speech motor development and to the speech production process in general. / Dissertation (MComm Path)--University of Pretoria, 2007. / Speech-Language Pathology and Audiology / Unrestricted
96

Sensorimotor integration and pain perception: mechanisms integrating nociceptive processing

Gombaut, Cindy 17 November 2021 (has links)
Chronic pain continues to be a prevalent condition in the U.S. costing the healthcare system billions of dollars annually with little success in treatment modalities. The goal of this study was to review nociceptive processing in the context of sensory and motor disorders where chronic pain often appears as a common symptom. An activation likelihood estimate (ALE) meta-analysis was performed on brain coordinates from articles containing sensory disorders (spinal cord injury and amputation) with or without pain performing a movement execution and movement imagery task and motor disorders (Parkinson’s disease and dystonia) performing a movement execution task. Aberrations found in the cortical activity of sensorimotor regions of both sensory and motor disorders suggests these disorders should be studied and treated as a dysfunction of sensorimotor integration instead of solely sensory or motor. Alterations of sensorimotor integration could be the necessary trigger for reorganization of cortical maps that alters nociceptive processing. Furthermore, abnormal activity found in the brain regions of both sensory and motor disorders involved in the cognitive and attentional modulation of pain suggests a once voluntary response has transitioned to a conditioned response that perpetuates the experience of pain.
97

Organization of Corticostriatal Projections From the Vibrissal Representations in the Primary Motor and Somatosensory Cortical Areas of Rodents

Calupca, Michelle A., Locknar, Sarah A., Zhang, Lili, Harrison, Theresa A., Hoover, Donald B., Parsons, Rodney L. 08 October 2001 (has links)
To characterize corticostriatal projections from rodent sensorimotor cortex, the anterograde tracers biotinylated dextran amine (BDA) and fluororuby (FR) were injected into the whisker representations of the primary motor (MI) and somatosensory (SI) cortices. Reconstructions of labeled terminals and their beaded varicosities in the neostriatum and thalamus were analyzed quantitatively to determine the degree of labeled overlap in both of these subcortical structures. Corticostriatal projections from the vibrissal representation in MI were more extensive than corresponding projections from SI. Both cortical areas sent dense projections to the dorsolateral neostriatum, but the MI vibrissal representation also projected to regions located more rostrally and medially. Despite these differences, both MI and SI projected to overlapping parts of the dorsolateral neostriatum. Tracer injections in both cortical areas also produced dense anterograde and retrograde labeling in the medial sector of the posterior complex of the thalamus (POm). Because POm is somatotopically organized and has reciprocal connections with both SI and MI cortices, the amount of labeled overlap in POm was used to indicate whether the tracers were injected into corresponding whisker representations of MI and SI. We found that the proportion of labeled overlap in the neostriatum was highly correlated with the amount of labeled overlap in POm. These results indicate that the rodent neostriatum receives convergent projections from corresponding regions in MI and SI cortex. Furthermore, the thalamocortical projections of the POm indicate that it may modulate corticostriatal outputs from corresponding representations in MI and SI.
98

THE IMPACT OF ORAL AFFERENTS ON JAW MOVEMENTS IN RABBITS

Chubb, Emma E. January 2020 (has links)
No description available.
99

The Kinematic & Neuromuscular Basis of Drosophila Larval Escape

Cooney, Patricia January 2022 (has links)
Escape behavior is the critical output of rapid sensorimotor processing in the brain that allows animals to sense danger and avoid it. The circuit structures and mechanisms that underlie escape are still under investigation. Drosophila larvae are an advantageous system for studying the neuromuscular circuitry of escape behavior. When threatened with harmful mechanical touch, heat, or light, larvae perform C-shaped bending and lateral rolling, followed by rapid forward crawling. The sensory input and neural circuitry that promotes escape in the larva have been extensively characterized, but we do not understand how bending and rolling motor programs are generated by the larval neuromuscular system. This work identifies the movement patterns, muscle activities, and motor circuit features that drive escape behavior. High-speed imaging approaches reveal that larvae select between four distinct, interchangeable patterns of escape rolling, and that each pattern consists of synchronous rotations of every segment as the larva rotates. Investigating electron microscopic reconstructions of premotor and motor neurons elucidates premotor to motor connectivity patterns that could underlie sequential muscle activity that circumnavigates the larva and propels synchronous rotation along the whole body. Volumetric Swept Confocally-Aligned Planar Excitation (SCAPE) microscopy uncovers that, unlike larval crawling, a well-studied form of larval locomotion that is driven by bilaterally symmetric peristaltic waves of muscle activity, the muscle activity during bending and rolling occurs in a circumferential sequence that is synchronous along the larva’s segments. Muscles neighboring the dorsal and ventral midlines of the larva demonstrate left-right symmetric activity during rolling, and ventral muscles appear to drive the propulsion. Shifts in magnitude of left-right symmetric activity in midline muscles allow the larva to transition from initial escape bending into escape rolling. Preliminary computational predictions of PMN activities confirm the likely necessity of strong ventral muscle coactivity for driving escape. Probing specific PMNs during rolling demonstrates robustness of circuits controlling escape and requires further investigation, alongside the role that sensory feedback could play in this behavior. Altogether, these data reveal a new circuit organization and motor activity pattern that underlie the coordination of muscles during an escape sequence. Future work could reveal circuit components necessary for escape, including the mechanistic basis for action selection, behavioral maintenance, and behavioral flexibility.
100

TRACK—a new algorithm and open‑source tool for the analysis of pursuit‑tracking sensorimotor integration processes

Böttcher, Adriana, Adelhöfer, Nico, Wilken, Saskia, Raab, Markus, Hoffmann, Sven, Beste, Christian 08 November 2024 (has links)
In daily life, sensorimotor integration processes are fundamental for many cognitive operations. The pursuit-tracking paradigm is an ecological and valid paradigm to examine sensorimotor integration processes in a more complex environment than many established tasks that assess simple motor responses. However, the analysis of pursuit-tracking performance is complicated, and parameters quantified to examine performance are sometimes ambiguous regarding their interpretation. We introduce an open-source algorithm (TRACK) to calculate a new tracking error metric, the spatial error, based on the identification of the intended target position for the respective cursor position. The identification is based on assigning cursor and target direction changes to each other as key events, based on the assumptions of similarity and proximity. By applying our algorithm to pursuit-tracking data, beyond replication of known effects such as learning or practice effects, we show a higher precision of the spatial tracking error, i.e., it fits our behavioral data better than the temporal tracking error and thus provides new insights and parameters for the investigation of pursuit-tracking behavior. Our work provides an important step towards fully utilizing the potential of pursuit-tracking tasks for research on sensorimotor integration processes.

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