Thèses : « SENSORIMOTORIA »

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CRISAFULLI, OSCAR. « Aspetti fisiologici e fisiopatologici dell’integrazione sensorimotoria ». Doctoral thesis, Università degli studi di Genova, 2021. http://hdl.handle.net/11567/1038237.

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My PhD program was mainly focused on the physiological and pathophysiological characteristics of sensorimotor integration. As part of this activity, I studied particular aspects of this topic in different populations of subjects: healthy young adults, visually impaired subjects, subjects suffering from Parkinson's disease and subjects suffering from cervical dystonia. Sensorimotor integration is a complex process that involves numerous central and peripheral nervous structures and is the basis of fundamental functions including the perception of the body in space and maintaining balance both in static and dynamic conditions. In the various studies published during the PhD program, I was able to investigate the stabilizing effects on the equilibrium of the haptic afference provided indirectly in the healthy young adult subject. Subsequently, we studied the effect of the stabilization given by the indirect haptic afference in blind and partially sighted subjects, then comparing the results with those obtained by providing the subjects with a direct haptic afference. Still on healthy young adult subjects, we investigated the effects of unilateral proprioceptive stimulation of the axial muscles on the podokinetic reflex, elicited by stepping in place on a rotating platform. In subjects suffering from Parkinson's disease, we evaluated the efficiency of the postural stabilization mechanisms necessary to counteract the perturbations induced by the motor resonance effect. In subjects suffering from cervical dystonia, we studied the characteristics of proprioceptive accuracy in the dystonic body segment and in a body segment not affected by the disease. In addition, a further study on a population of subjects suffering from cervical dystonia is currently under review, this time concerning the balance and kinematic characteristics of gait. The purpose of this thesis is to summarize the scientific activity of my PhD program.

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RIZZI, EZIA. « A JOURNEY THROUGH TIME. SPACE-TIME REPRESENTATION IN ADULTS AND CHILDREN ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2019. http://hdl.handle.net/10281/243942.

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È noto che la mente umana spesso crea una rappresentazione del tempo attraverso dimensioni più concrete, come lo spazio. Abitualmente, parliamo del passato riferendoci allo spazio dietro di noi e al futuro allo spazio di fronte a noi. Questa tesi di dottorato esplora l'origine e lo sviluppo dell'associazione tra tempo e spazio nell'infanzia e nell'età adulta. La prima sezione fornisce una panoramica del background teorico e discute gli studi precedenti che si sono focalizzati su questo argomento. Descriviamo gli elementi mancanti e individuiamo che il tipo di informazioni elaborate (cioè gli eventi che si riferiscono alla memoria personale e non personale) possano influenzare la costruzione della linea del tempo mentale e i relativi fotogrammi spaziali di riferimento coinvolti. Il secondo capitolo sperimentale indaga direttamente se eventi personali e non personali sono mappati in modo diverso nello spazio in età adulta, coinvolgendo madrelingua italiana. I risultati descritti mostrano che mentre gli eventi personali sono mappati preferenzialmente lungo lo spazio sagittale, gli eventi non personali sono più probabilmente mappati sullo spazio orizzontale. Questi risultati sono stati replicati in un campione di madrelingua adulti inglesi utilizzando una procedura simile e indicano che il tipo di contenuto elaborato in memoria influisce sul modo in cui l'individuo rappresenta il tempo nello spazio. Il terzo capitolo è incentrato sull'ontogenesi della linea temporale mentale. Un primo studio ha esplorato la rappresentazione di eventi personali e non personali lungo lo spazio sagittale in bambini madrelingua inglese della scuola elementare, estendendo così la principale domanda teorica alla base di questa tesi a livello dello sviluppo. In un secondo studio, i bambini della scuola elementare italiana sono stati coinvolti in due compiti che esploravano le origini linguistiche e sensomotorie della linea mentale del tempo sagittale. I risultati indicano che la rappresentazione del tempo lungo lo spazio sagittale si basa fortemente su processi sensorimotori già in giovane età. Insieme, questo corpus di prove fornisce nuove intuizioni sui meccanismi cognitivi e sensomotori che guiderebbero gli umani a rappresentare il tempo lungo le coordinate spaziali.
It is well known that the human mind often creates a representation of time through more concrete dimensions, such as space. Habitually, we talk about past referring to the space behind us and about future referring to the space in front of us. This doctoral thesis explores the origin and development of the association between time and space in childhood and adulthood. The first section provides an overview of the theoretical background and discuss previous studies that have been focused on this topic. We outline the missing pieces of evidence and pinpoint that the type of information processed at hand (i.e., events referring to personal and non-personal memory) may impact on how the mental time line is constructed and on the relative spatial frames of reference involved. The second, empirical chapter investigates directly whether personal and non-personal events are differently mapped on space in adulthood, by involving native Italian speakers. The results described show that whereas personal events are preferentially mapped along the sagittal space, non-personal events are more likely mapped on the horizontal space. These findings were replicated in a sample of English adult speakers using a similar procedure and indicate that the type of content processed in memory affects how the individual represents time in space. The third chapter is focused on the ontogeny of the mental time line. A first study explored the representation of personal and non-personal events along the sagittal space in native English primary school children, thus extending the main theoretical question underlying this thesis at the developmental level. In a second study, Italian primary school children were involved in two tasks probing the linguistic and sensorimotor origins of the sagittal mental time line. Results indicate that the representation of time along the sagittal space strongly relies on sensorimotor processes already from a young age. Together, this body of evidence provides new insights on the cognitive and sensorimotor mechanisms that would drive humans to represent time along spatial coordinates.

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Bütepage, Judith. « Social Sensorimotor Contingencies ». Thesis, KTH, Datorseende och robotik, CVAP, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-185463.

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As the field of robotics advances, more robots are employed in our everyday environment. Thus, the implementation of robots that can actively engage in physical collaboration and naturally interact with humans is of high importance. In order to achieve this goal, it is necessary to study human interaction and social cognition and how these aspects can be implemented in robotic agents. The theory of social sensorimotor contingencies hypothesises that many aspects of human-human interaction depend on low-level signalling and mutual prediction. In this thesis, I give an extensive account of these underlying mechanisms and how research in human-robot interaction has incorporated this knowledge. I integrate this work in human-human and human-robot interaction into a coherent framework of social sensorimotor contingencies. Furthermore, I devise a generative model based on low-level latent features that allows inferences about other agent's behaviour. With this simulation experiment I demonstrate that embodied cognition can explain behaviour that is usually interpreted with help of high-level belief and mental state inferences. In conclusion, the implementation of these low-level processes in robots creates a more natural and intuitive interaction without the need of high-level representations.

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Downey, Adrian. « Radical sensorimotor enactivism ». Thesis, University of Sussex, 2017. http://sro.sussex.ac.uk/id/eprint/67116/.

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In this thesis I develop a novel approach to conscious perception, which I label “radical sensorimotor enactivism” (RSE). In chapter one, I explain how the development of RSE is guided by the tenets of activity and knowledge-how. In chapter two, I outline and explain RSE. Throughout the thesis, I will pit RSE against cognitivist accounts of conscious perception and argue that RSE is to be preferred. In chapters three and four, I highlight two problems facing cognitivist accounts of conscious perception which RSE avoids. I argue that cognitivist accounts of conscious perception face the ‘hard problem of perceptual consciousness', whilst RSE can provide a phenomenologically plausible deflation of this problem. I next explain why cognitivist accounts are incapable of providing a satisfactory explanation of split-brain syndrome. Then, I argue that RSE can provide a parsimonious explanation of this syndrome. Theories predicated on activity and knowledge-how are often rejected for being incapable of accounting for the brain's role in conscious perception. In chapter five, I argue that RSE can account for the brain's role by adopting a non-representational version of predictive processing (PP). Moreover, I argue that the resultant account improves upon cognitivist alternatives. Then, in chapter six, I argue that even representational explanations of PP can be subsumed within RSE by accepting fictionalism about their representational posits. Consequently, I conclude that RSE cannot be objected to for failing to account for the brain's role in conscious perception. Finally, in chapter seven, I discuss ‘non-veridical' experiences. Accounts like RSE are often rejected because it is thought they are incapable of explaining the existence of these phenomena. I explain how the existence of such phenomena is wholly compatible with the truth of RSE. Thus, I conclude that RSE should not be rejected solely on the basis that non-veridical experiences exist.

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Säfström, Daniel. « Sensorimotor transformations during grasping movements ». Doctoral thesis, Umeå universitet, Integrativ medicinsk biologi, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-781.

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‘Sensorimotor transformations’ are processes whereby sensory information is used to generate motor commands. One example is the ‘visuomotor map’ that transforms visual information about objects to motor commands that activates various muscles during grasping movements. In the first study we quantified the relative impact (or ‘weighting’) of visual and haptic information on the sensorimotor transformation and investigated the principles that regulates the weighting process. To do this, we let subjects perform a task in which the object seen (visual object) and the object grasped (haptic object) were physically never the same. When the haptic object became larger or smaller than the visual object, subjects in the following trials automatically adapted their maximum grip aperture (MGA) when reaching for the object. The adaptation process was quicker and relied more on haptic information when the haptic objects increased in size than when they decreased in size. As such, sensory weighting is molded to avoid prehension error. In the second study we investigated the degree to which the visuomotor map could be modified. Normally, the relationship between the visual size of the object (VO) and the MGA can be expressed as a linear relationship, where MGA = a + b * VO. Our results demonstrate that subjects inter- and extrapolate in the visuomotor map (that is, they are reluctant to abandon the linear relationship) and that the offset (a) but not the slope (b) can be modified. In the third study, we investigated how a ‘new’ sensorimotor transformation can be established and modified. We therefore replaced the normal input of visual information about object size with auditory information, where the size of the object was log-linearly related to the frequency of a tone. Learning of an audiomotor map consisted of three distinct phases: during the first stage (~10-15 trials) there were no overt signs of learning. During the second stage there was a period of fast learning where the MGA became scaled to the size of the object until the third stage where the slope was constant. The purpose of the fourth study was to investigate the sensory basis for the aperture adaptation process. To do that, the forces acting between the fingertips and the object was measured as the subjects adapted. Our results indicate that information about when the fingers contacts the object, that is, the ‘timing’ of contact, is likely to be used by the CNS to encode an unexpected object size. Since injuries and disease can affect the sensorimotor transformations that controls the hand, knowledge about how these processes are established and modified may be used to develop techniques for sensory substitution and other rehabilitation strategies.

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Allison, Robert Scott. « Sensorimotor processing of vertical disparity ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ27276.pdf.

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Säfström, Daniel. « Sensorimotor transformations during grasping movements / ». Umeå : Department of Integrative Medical Biology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-781.

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Liu, Ting Ting. « Spinal interneurons in sensorimotor integration ». Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/1299/.

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Even though spinal cord research has expanded enormously during the past decades, we still lack a precise understanding of how spinal interneuron networks perfectly integrate sensory feedback with motor control, and how these neuron circuits give rise to specific functions. The present study thus has three basic aims: (1) to investigate propriospinal interneurons connecting rostral and caudal lumbar spinal cord in the rat; (2) to investigate input properties of identified spinal interneurons interposed in different pathways; (3) to investigate cholinergic terminals in the ventral horn of adult rat and cat. To realize the first aim, the B-subunit of cholera toxin (CTb) was injected into the motor nuclei at the L1 or L3 segmental level to retrogradely label propriospinal interneurons in the L5 segment of rat spinal cord. These cells had a clear distribution pattern which showed that they were located mainly in ipsilateral dorsal horn and contralateral lamina VIII. A series triple-labelling experiments revealed that about 1/4 of the CTb-positive cells were immunoreactive for calbindin and/or calretinin. It was also found that a small population of CTb labelled cells were cholinergic and were observed mainly in three locations: lamina X, the medial part of intermediate zone and lamina VIII. In addition, injection of CTb also anterogradely labelled axon terminals, which arose from the commissural interneurons (CINs) within the site of injection, crossed the midline and aroborized in the contralateral lateral motor nuclei of the L5 segment. The neurotransmitter systems in labelled axon terminals of CINs were investigated by using antibodies raised against specific transmitter-related proteins. The results showed that approximately 3/4 terminals were excitatory and among those excitatory terminals about 3/4 forming contacts with motoneurons. To achieve the second aim, 21 interneurons located in the intermediate zone and lamina VIII from 7 adult cats were characterised electrophysiologically and labelled intracellularly with Neurobiotin. Seventeen of these cells were activated monosynaptically from primary muscle afferents but the remaining four cells received monosynaptic inputs from the medial longitudinal fasciculus (MLF). Quantitative analysis revealed that cells in the first group received many contacts from excitatory terminals that were immunoreactive for the vesicular glutamate transporter 1 (VGLUT1) but those cells from the second group received few contacts of this type and were predominantly contacted by terminals immunoreactive for vesicular glutamate transporter 2 (VGLUT2). This result was as predicted because VGLUT1 is found principally in the terminals of myelinated primary afferent axons whereas VGLUT2 is located in the terminals of interneurons in the spinal cord. Interneurons in the first group were then characterised as excitatory and inhibitory on the basis of the transmitter content contained within their axon terminals. Although there was a greater density of VGLUT1 contacts on excitatory rather than inhibitory cells, the difference was not statistically significant. GABAergic terminals formed close appositions with VGLUT1 contacts on both excitatory and inhibitory cells. These appositions were likely to be axoaxonic synapses which mediate presynaptic inhibition. In addition, the densities of VGLUT1 and VGLUT2 contacts on 30 dorsal horn CINs and 60 lamina VIII CINs that were retrogradely labelled with CTb from 3 adult rats were compared. The results showed that VGLUT2 terminals formed the majority of excitatory inputs to both dorsal horn and lamina VIII CINs but dorsal horn CINs received a significantly greater density of VGLUT1/2 inputs than lamina VIII CINs. In order to achieve the third aim, i.e. whether glutamate is a cotransmitter at motoneuron axon collateral terminals in the ventral horn, a series of anatomical experiments were performed on axon collaterals obtained from motoneurons from an adult cat and retrogradely labelled by CTb in adult rats. There was no evidence to support the presence of vesicular glutamate transporters in motoneuron axon terminals of either species. In addition, there was no obvious relationship between motoneuron terminals and R2 subunit of the AMPA receptor (GluR2). However, a population of cholinergic terminals in lamina VII, which did not originate from motoneurons, was found to be immunoreactive for VGLUT2 and formed appositions with GluR2 subunits. These terminals were smaller than motoneuron terminals and, unlike them, formed no relationship with Renshaw cells. The evidence suggests that glutamate does not act as a cotransmitter with acetylcholine at central synapses of motoneurons in the adult cat and rat. However, glutamate is present in a population of cholinergic terminals which probably originate from interneurons where its action is via an AMPA receptor. In conclusion, the present studies add to the understanding of the organization of neuronal networks involved in sensorimotor integration. Propriospinal interneurons located within the lumbar segments have extensive intra-segmental projections to motor nuclei. First order interneurons interposed in reflex pathways and descending pathways receive a significantly different pattern of inputs. A similar proportion of monosynaptic excitatory input from primary afferents has been found in both excitatory and inhibitory interneurons and these two types of cells are subject to presynaptic inhibitory control of this input.

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Li, Jingxian. « Reinforcement learning using sensorimotor traces ». Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45590.

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The skilled motions of humans and animals are the result of learning good solutions to difficult sensorimotor control problems. This thesis explores new models for using reinforcement learning to acquire motion skills, with potential applications to computer animation and robotics. Reinforcement learning offers a principled methodology for tackling control problems. However, it is difficult to apply in high-dimensional settings, such as the ones that we wish to explore, where the body can have many degrees of freedom, the environment can have significant complexity, and there can be further redundancies that exist in the sensory representations that are available to perceive the state of the body and the environment. In this context, challenges to overcome include: a state space that cannot be fully explored; the need to model how the state of the body and the perceived state of the environment evolve together over time; and solutions that can work with only a small number of sensorimotor experiences. Our contribution is a reinforcement learning method that implicitly represents the current state of the body and the environment using sensorimotor traces. A distance metric is defined between the ongoing sensorimotor trace and previously experienced sensorimotor traces and this is used to model the current state as a weighted mixture of past experiences. Sensorimotor traces play multiple roles in our method: they provide an embodied representation of the state (and therefore also the value function and the optimal actions), and they provide an embodied model of the system dynamics. In our implementation, we focus specifically on learning steering behaviors for a vehicle driving along straight roads, winding roads, and through intersections. The vehicle is equipped with a set of distance sensors. We apply value-iteration using off-policy experiences in order to produce control policies capable of steering the vehicle in a wide range of circumstances. An experimental analysis is provided of the effect of various design choices. In the future we expect that similar ideas can be applied to other high-dimensional systems, such as bipedal systems that are capable of walking over variable terrain, also driven by control policies based on sensorimotor traces.

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Vetter, Philipp. « Context estimation in sensorimotor control ». Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368950.

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Houde, John Francis. « Sensorimotor adaptation in speech production ». Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10273.

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Marjanović, Matthew J. (Matthew Josef). « Learning maps between sensorimotor systems ». Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11417.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.
Includes bibliographical references (p. 55-56).
by Matthew J. Marjanovíc.
M.S.

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Turnham, Edward James Anthony. « Meta-learning in sensorimotor control ». Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610592.

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Takagi, Atsushi. « Mechanism of interpersonal sensorimotor interaction ». Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/45547.

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This thesis uncovers the mechanism of interaction between human partners in continuous contact. During such sensorimotor interaction, I propose that people interpret their partner's desired movement through the forces they feel. The evidence of this interpersonal goal integration mechanism comes from three behavioural experiments and computational modelling of their results. Novel dual-robotic interfaces were used in the experiments for two reasons: first, to eliminate the partner's gaze as it was found to influence the behaviour of interacting pairs of subjects. Second, to systematically and quantitatively measure the effects of sensorimotor interaction on task performance and adaptations in muscular activity, i.e. motor force and joint impedance. The first experiment revealed that sensorimotor interaction during a tracking task, where partners track a randomly moving target with their cursor, enabled both the worse and better partners in the pair to improve at tracking. This mutually beneficial effect of interaction, regardless of the partner's skill, cannot be explained by existing theories in psychology and neuroscience, but the discovered interpersonal goal integration mechanism does capture this behaviour; when this interaction mechanism was implemented in a robot partner, people interacting with this robot behaved similarly to those during interpersonal interaction. Adaptations in the muscular activity were observed in the second experiment, where pairs were rigidly or weakly coupled during a tracking task. The better partners increased their motor force and joint impedance, whereas the worse partners decreased both. The interaction mechanism also predicted these changes in the motor force. Finally, an experiment where four partners interacting together during a tracking task showed that the best partner's performance was not hindered by many worse partners, which was also predicted by the interpersonal goal integration mechanism. The interpersonal goal integration mechanism is the first robotic algorithm to exhibit human-like behaviour during sensorimotor interaction. It has applications where continuous contact with a human partner is critical, such as the transport of large objects or in the co-operative control of lower-limb exoskeletons. It offers a new approach for robotic rehabilitation through continuous, physical interaction which exploits the benefits of simultaneous action observation and physical training. Finally, the interaction mechanism may be used as an investigative and therapeutic tool for autism spectrum disorder (ASD). Individuals affected by ASD commonly lack the ability to extrapolate someone's goal by observing their actions alone. Similarly, they may lack the ability to estimate a partner's desired movement from observing haptics forces alone, thus the interpersonal goal integration mechanism may shed light on the specific differences between people with ASD and healthy individuals.

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Vincent, Jacob Adam. « Sensorimotor Deficits Following Oxaliplatin Chemotherapy ». Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1496136263522854.

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Rönnqvist, Kim. « Multimodal characterisation of sensorimotor oscillations ». Thesis, Aston University, 2013. http://publications.aston.ac.uk/19564/.

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The studies in this project have investigated the ongoing neuronal network oscillatory activity found in the sensorimotor cortex using two modalities: magnetoencephalography (MEG) and in vitro slice recordings. The results have established that ongoing sensorimotor oscillations span the mu and beta frequency region both in vitro and in MEG recordings, with distinct frequency profiles for each recorded laminae in vitro, while MI and SI show less difference in humans. In addition, these studies show that connections between MI and SI modulate the ongoing neuronal network activity in these areas. The stimulation studies indicate that specific frequencies of stimulation affect the ongoing activity in the sensorimotor cortex. The continuous theta burst stimulation (cTBS) study demonstrates that cTBS predominantly enhances the power of the local ongoing activity. The stimulation studies in this project show limited comparison between modalities, which is informative of the role of connectivity in these effects. However, independently these studies provide novel information on the mechanisms on sensorimotor oscillatory interaction. The pharmacological studies reveal that GABAergic modulation with zolpidem changes the neuronal oscillatory network activity in both healthy and pathological MI. Zolpidem enhances the power of ongoing oscillatory activity in both sensorimotor laminae and in healthy subjects. In contrast, zolpidem attenuates the “abnormal” beta oscillatory activity in the affected hemisphere in Parkinsonian patients, while restoring the hemispheric beta power ratio and frequency variability and thereby improving motor symptomatology. Finally we show that independent signals from MI laminae can be integrated in silico to resemble the aggregate MEG MI oscillatory signals. This highlights the usefulness of combining these two methods when elucidating neuronal network oscillations in the sensorimotor cortex and any interventions.

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Cannon, Peter Robert. « Does sensorimotor fluency influence affect ? » Thesis, Bangor University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505950.

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Jasper, Isabelle. « Circadian rhythms in sensorimotor control ». Tönning Lübeck Marburg Der Andere Verl, 2009. http://d-nb.info/997031034/04.

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Dick, Frederic. « Language in a sensorimotor brain / ». Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3091337.

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Paracampo, Riccardo <1986&gt. « Sensorimotor Network in Social Cognition ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/7878/1/ParacampoRiccardo_SensorimotorNetworkSocialCognition.pdf.

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Our motor and somatosensory cortices originally evolved to control our movement through the environment. In the past decade, one of the most exciting developments in cognitive neuroscience is the discovery that the same sensorimotor brain regions that are used to control our body are involved in the perception of others’ actions, sensations and emotions. Human beings are equipped with a mechanism mapping perceptual representations of actions, sensations, and emotions onto sensorimotor representations, thus, perception of others might be inherently grounded in the same brain regions involved in first-hand subjective experiences. While the notion that observing, or imagining actions, emotions, and sensations in others triggers vicarious activations in the sensorimotor network is widely accepted, evidence about the specific role of these activations in social cognition is meagre and still largely based on correlational data. The experiments included in the present thesis aim at exploring the functional role of the sensorimotor network in understanding others’ internal emotional and cognitive states. We used neuromodulation tools to interfere with brain activity in regions involved in moving and sensing the body while participants were asked to understand others’ emotions or intentions. In experiment 1 to 7 we focused on the ability to accurately understand amusement from observed smiles, while in experiment 8 to 10 we explored the ability to rate the pain felt by another individual when her/his experience is described only through text. Our results show that interference with activity within somatosensory and motor cortices impairs participants’ ability to understand others’ emotions. Combining complex naturalistic tasks to neuromodulation tools, the present thesis sheds novel light on the behavioural relevance of vicarious activations in the sensorimotor network, by establishing a strong and direct causal link between sensorimotor brain networks and others’ understanding that was only suggested in the past.

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Biswas, Amitava. « Perioral sensorimotor integration in Parkinson's disease ». [Bloomington, Ind.] : Indiana University, 2005. http://wwwlib.umi.com/dissertations/fullcit/3183913.

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Aguilar, Lleyda David. « Sensorimotor decision-making with moving objects ». Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/461673.

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Moving is essential for us to survive, and in countless occasions we move in response to visual information. However, this process is characterized as uncertain, given the variability present both at the sensory and motor stages. A crucial question, then, is how to deal with this uncertainty in order for our actions to lead to the best possible outcomes. Statistical decision theory (SDT) is a normative framework that establishes how people should make decisions in the presence of uncertainty. This theory identifies the optimal action as that which maximizes the expected reward (outcome) of the situation. Movement planning can be reformulated in terms of SDT, so that the focus is placed on the decisional component. Some experimental work making use of this theoretical approach has concluded that humans are optimal movement planners, while other has identified situations where suboptimality arises. However, sensorimotor decision-making within SDT has commonly eluded scenarios of interaction with moving objects. At the same time, the work devoted to moving objects has not focused on the decisional aspect. The present thesis aims at bridging both fields, with each of our three studies trying to answer different questions. Given the spatiotemporal nature of situations with moving objects, we can plan our actions by relying on both temporal and spatial cues provided by the object. In Study I we investigated whether exploiting more one type of these visual cues led to a better performance, as defined by the reward given after each action. In our task we presented a target, which could vary in speed and motion time, approaching a line. Participants responded to stop the target and were rewarded according to its proximity to the line. Responding after the target crossed the line was penalized. We discovered that those participants planning their responses based on time-based motion cues had a better performance than those monitoring the target’s changing spatial position. This was due to the former approach circumventing a limitation imposed by the resolution of the visual system. We also found that viewing the object for longer favored time-based responses, as mediated by longer integration time. Finally, we used existing SDT models to obtain a reference of optimality, but we defend that these models are limited to interpret our data. Study II built on our previous findings to explore whether the use of temporal cues could be learnt. We took our previous paradigm and adapted it so that reward was manipulated after each task in order to foster exploiting temporal information. There was no evidence for learning taking place, since participants using temporal cues did so from the start of the experiment. Whether other methods reward can shape the use of certain cues, and why some people naturally tend to make more use of temporal information, still remain elusive. Study III deepened our knowledge on which variability people consider when planning their responses. We hypothesized that the reason why people are suboptimal (as defined by SDT) in many situations is because they represent only their measurement variability, roughly equivalent to the execution noise, while excluding the variability created by sudden changes in their planning. We took previous data and used a Kalman filter to extract each participant’s measurement variability. We then used it to compute SDT-derived optimal responses, and discovered that they explained well our data, giving support to our hypothesis. We also found evidence for participants using the information provided by reward both to avoid being penalized and to choose the point at which to stabilize their responses. Taken together, our experimental work presents interaction with moving objects as a complex set of situations where different information guides our response planning. Firstly, visual cues of different origin. Secondly, our variability, coming from many sources, some of which may not be considered. Finally, the outcomes related to each action.
Moure’s és essencial per a la nostra supervivència, i en incomptables ocasions ens movem en resposta a informació visual. Tanmateix, aquest procés és incert, donada la variabilitat present tant a l'estadi sensorial com en el motor. Una pregunta crucial, doncs, és com gestionar aquesta incertesa perquè les nostres accions portin a les millors conseqüències possibles. La teoria de la decisió estadística (Statistical decision theory, SDT) és un marc teòric normatiu que estableix com la gent hauria de fer decisions en presència d'incertesa. Aquesta teoria identifica l'acció òptima amb aquella que maximitza la recompensa (entesa com a conseqüència) esperada de la situació. La planificació del moviment pot ser reformulada en termes de SDT, de tal manera que s’emfatitza el component decisional. Diferents treballs experimentals que han fet servir aquesta aproximació teòrica han conclòs que els humans som planificadors de moviment òptims, mentre que altres han identificat situacions on la suboptimalitat sorgeix. No obstant això, la presa de decisions sensoriomotora des de SDT normalment ha ignorat escenaris que requereixen d'interacció com objectes en moviment. Alhora, els treballs dedicats als objectes en moviment no s'han centrat en l'aspecte de decisió. La present tesi es proposa acostar els dos camps, amb cada un dels nostres tres estudis intentant respondre diferents preguntes. L’Estudi I descobrí que, per planificar les nostres decisions, fer servir informació temporal portà a un millor rendiment que fer servir informació espacial, i això fou facilitat per veure l'objecte durant més temps. També vam criticar la limitació de certs models d’SDT per interpretar els nostres dades. L'Estudi II intentà promoure l'ús d'informació temporal, tot i que no s’aconseguí fomentar l’aprenentatge. Finalment, l’'Estudi III trobà que la raó per la qual la gent és subòptima en moltes situacions es deu al fet que representa només la seva variabilitat de mesura, més o menys equivalent al soroll d'execució, mentre que s'exclou la variabilitat creada per sobtats canvis en la planificació de la resposta. També trobàrem que els participants van usar la informació donada per la recompensa tant per evitar ser penalitzats com per escollir el punt on estabilitzar les seves respostes.

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Akpinar, Selcuk. « Sensorimotor Performance Asymmetries And Hand Preference ». Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613278/index.pdf.

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This dissertation presents three experiments to investigate the general distribution of hand preference across a reachable working space, as well as the effect of sensory information about the reaching hand, and if this distribution is affected by long term practice. In addition, the underlying mechanisms of hand preference behavior were investigated with the obtained kinematic data. Experiment 1 explored the distribution of hand preferences across the workspace among non-athlete right-handed participants, as well as the role that visual feedback might play in this distribution. Experiment 2 tested the hypothesis, if occlusion of visual feedback influences hand preference, accordingly interlimb differences. The third final experiment examined the effect of long term practice on hand preference among right-handed elite fencers. The first study showed that the choice of arms is related to the energetic cost and dynamic efficiency of the movements. The results of the second experiment displayed that the choice of hands changes under no visual feedback condition, demonstrating that the choice is active and not habitual, depending on sensorimotor performance asymmetries. The final experiment demonstrated that elite athletes have different patterns of limb selection than non- athletes. Athletes, specifically fencers, show improved coordination in their non-dominant arms, which apparently increases the selection of this arm for reaching. Overall, it was concluded that hand preference depends on sensorimotor performance asymmetries and influenced by the long term practice.

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Sinason, Marek Bron David. « The cognitive context of sensorimotor synchronisation ». Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4213/.

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The cognitive context of sensorimotor synchronisation (SMS) starts with the assumption that performance of relatively simple behaviour emerges through the background noise of a psychological context. Despite progress, and growth in understanding of the component sources of variability in cognition, perception and action, the role of more executive cognitive processes have not yet been well integrated to successful models of sensorimotor synchronisation. This thesis presents a series of studies investigating more precisely the role of executive control functions on the variability of repetitive production of movements. The findings of the 5 experiments presented are discussed in relation to existent theories and ongoing debates in the field of sensorimotor synchronisation. The contribution of this research highlights the importance of executive processes often overlooked when assessing the nature of variability in rhythmic movement production and opens some clear pathways for future research, adjustments to current models used, and novel paradigms.

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Ghahramani, Zoubin. « Computation and psychophysics of sensorimotor integration ». Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11123.

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Silverman, David. « The sensorimotor theory of perceptual experience ». Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/5544.

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The sensorimotor theory is an influential, non-mainstream account of perception and perceptual consciousness intended to improve in various ways on orthodox theories. It is often taken to be a variety of enactivism, and in common with enactivist cognitive science more generally, it de-emphasises the theoretical role played by internal representation and other purely neural processes, giving theoretical pride of place instead to interactive engagements between the brain, non-neural body and outside environment. In addition to offering a distinctive account of the processing that underlies perceptual consciousness, the sensorimotor theory aims to offer a new and improved account the logical and phenomenological character of perceptual experience, and the relation between physical and phenomenal states. Since its inception in a 2001 paper by O'Regan and Noë, the theory has prompted a good deal of increasingly prominent theoretical and practical work in cognitive science, as well as a large body of secondary literature in philosophy of cognitive science and philosophy of perception. In spite of its influential character, many of the theory's most basic tenets are incompletely or ambiguously defined, and it has attracted a number of prominent objections. This thesis aims to clarify the conceptual foundations of the sensorimotor theory, including the key theoretical concepts of sensorimotor contingency, sensorimotor mastery, and presence-as-access, and defends a particular understanding of the respective theoretical roles of internal representation and behavioural capacities. In so doing, the thesis aims to highlight the sensorimotor theory's virtues and defend it from some leading criticisms, with particular attention to a response by Clark which claims that perception and perceptual experience plausibly depend on the activation of representations which are not intimately involved in bodily engagements between the agent and environment. A final part of the thesis offers a sensorimotor account of the experience of temporally extended events, and shows how with reference to this we can better understand object experience.

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Wieczerzak, Krystyna Blanka. « Sensorimotor Analysis of Oxaliplatin Treated Rats ». Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1432856752.

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Boyer, Eric. « Continuous auditory feedback for sensorimotor learning ». Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066165/document.

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Notre système sensorimoteur a développé une relation particulière entre nos actions et le retour sonore qui en découle. Les systèmes de captation gestuelle et les technologies audio permettent de manipuler ce retour sonore par la sonification interactive du mouvement. Nous explorons dans divers cadres expérimentaux la contribution de la sonification à l'apprentissage moteur dans les systèmes interactifs. Tout d'abord, nous montrons que le système auditif intègre des indices acoustiques issus du mouvement pour le contrôle moteur. Des représentations de l'espace émergent de ces indices et sont transformées en commandes motrices. Le cas d'un objet virtuel sonore nous apprend que ces représentations audiomotrices influencent les stratégies d'exploration et permettent des cas de substitution sensorielle par le son. Ensuite, nous mesurons qu'un retour sonore continu permet d'améliorer significativement la performance à une tâche de poursuite. La sonification de l'erreur et des paramètres de la tâche aident à la performance mais montrent des effets différents sur l'apprentissage. Nous observons également que la sonification du mouvement de l'utilisateur augmente l'énergie contenue dans le geste et prévient la dépendance au retour sonore. Enfin, nous présentons le concept de tâche sonore dans lequel la cible est présentée et s'exprime sous forme de paramètres sonores à reproduire. Les résultats montrent qu'une adaptation motrice peut être provoquée par des indices acoustiques seuls. Ce travail permet de dégager des principes importants du design de l'interaction geste-son, et présente des applications originales comme des scénarios interactifs pour la rééducation
Our sensorimotor system has developed a specific relationship between our actions and their sonic outcomes, which it interprets as auditory feedback. The development of motion sensing and audio technologies allows emphasizing this relationship through interactive sonification of movement. We propose several experimental frameworks (visual, non-visual, tangible, virtual) to assess the contribution of sonification to sensorimotor control and learning in interactive systems. First, we show that the auditory system integrates dynamic auditory cues for online motor control, either from head or hand movements. Auditory representations of space and of the scene can be built from audio features and transformed into motor commands. The framework of a virtual sonic object illustrates that auditory-motor representations can shape exploratory movement features and allow for sensory substitution. Second, we measure that continuous auditory feedback in a tracking task helps significantly the performance. Both error and task sonification can help performance but have different effects on learning. We also observe that sonification of user’s movement can increase the energy of produced motion and prevent feedback dependency. Finally, we present the concept of sound-oriented task, where the target is expressed as acoustic features to match. We show that motor adaptation can be driven by interactive audio cues only. In this work, we highlight important guidelines for sonification design in auditory-motor coupling research, as well as applications through original setups we developed, like perceptual and physical training, and playful gesture-sound interactive scenarios for rehabilitation

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Greuel, Alison Jeanne. « Sensorimotor influences on speech perception in infancy ». Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50782.

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The multisensory nature of speech, and in particular, the modulatory influence of one’s own articulators during speech processing, is well established in adults. However, the origins of the sensorimotor influence on auditory speech perception are largely unknown, and require the examination of a population in which a link between speech perception and speech production is not well-defined; by studying preverbal infant speech perception, such early links can be characterized. Across three experimental chapters, I provide evidence that articulatory information selectively affects the perception of speech sounds in preverbal infants, using both neuroimaging and behavioral measures. In Chapter 2, I use a looking time procedure to show that in 6-month-old infants, articulatory information can impede the perception of a consonant contrast when the related articulator is selectively impaired. In Chapter 3, I use the high-amplitude suck (HAS) procedure to show that neonates are able to discriminate and exhibit memory for the vowels /u/ and /i/; however, the information from the infants’ articulators (a rounded lip shape) seems to only marginally affect behavior during the learning of these vowel sounds. In Chapter 4, I co-register HAS with a neuroimaging technique – Near Infrared Spectroscopy (NIRS) – and identify underlying neural networks in newborn infants that are sensitive to the sensorimotor-auditory match, in that the vowel which matches the lip shape (/u/) is processed differently than the vowel that is not related to the lip shape (/i/). Together, the experiments reported in this dissertation suggest that even before infants gain control over their articulators and speak their first words, their sensorimotor systems are interacting with their perceptual systems as they process auditory speech information.
Arts, Faculty of
Psychology, Department of
Graduate

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Bradley, Susanne. « Applications of machine learning in sensorimotor control ». Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54570.

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There have been many recent advances in the simulation of biologically realistic systems, but controlling these systems remains a challenge. In this thesis, we focus on methods for learning to control these systems without prior knowledge of the dynamics of the system or its environment. We present two algorithms. The first, designed for quasistatic systems, combines Gaussian process regression and stochastic gradient descent. By testing on a model of the human mid-face, we show that this combined method gives better control accuracy than either regression or gradient descent alone, and improves the efficiency of the optimization routine. The second addresses the trajectory-tracking problem for dynamical systems. Our method automatically learns the relationship between muscle activations and resulting movements. We also incorporate passive dynamics compensation and propose a novel gain-scheduling algorithm. Experiments performed on a model of the human index finger demonstrate that each component we add to the control formulation improves performance of fingertip precision tasks.
Science, Faculty of
Computer Science, Department of
Graduate

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Harrison, Thomas Clarke. « Light-based mapping of mouse sensorimotor cortex ». Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44131.

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The motor cortex controls voluntary, skilled movements. It possesses a basic somatotopic organization, but its fine structure remains controversial. Although the reorganization of motor cortex after brain injury is believed to be a critical part of behavioral recovery, our understanding of this process has been constrained by technical limitations. Conventional methods for mapping the motor cortex rely on the insertion of intracortical stimulating electrodes into the brain. We developed a new method for light-based motor mapping that is faster, less invasive, and better suited to repeated mapping in both acute and longitudinal studies. Using this technique, we identified a functional subdivision of the mouse forelimb motor representation according to the direction of movement. Pharmacological and anatomical experiments revealed that the expression of complex movements requires the intact function of the intracortical circuitry, whereas the basic topography of movement in motor cortex may arise primarily from the arrangement of output projections. We also refined methods for intrinsic optical signal sensory imaging, which can be combined with light-based motor mapping to obtain a more complete map of sensorimotor cortex. Performing light-based mapping of sensorimotor cortex for weeks before and after targeted photothrombotic stroke allowed us to monitor cortical reorganization on an unprecedented timescale. We found that if forelimb somatosensory cortex was destroyed by targeted stroke, the forelimb motor cortex was able to incorporate a reorganized sensory map. As a consequence of this increased integration of sensory and motor function after stroke, however, the structure of the motor map was altered, evidenced by a decrease in spatial autocorrelation. Strokes in motor cortex caused increased motor output in peri-infarct cortex, but had no effect on the location or sensitivity of the forelimb somatosensory representation. Light-based motor mapping has provided new insights into both the functional organization of motor cortex and its capacity for spontaneous reorganization after stroke.

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Ingram, Helen Anne. « Sensorimotor integration and control in human movement ». Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302009.

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Hamilton, Antonia Felicity de Courcy. « The role of noise in sensorimotor control ». Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404931.

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Sadeghi, Mohsen. « Representation and interaction of sensorimotor learning processes ». Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/278611.

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Human sensorimotor control is remarkably adept at utilising contextual information to learn and recall systematic sensorimotor transformations. Here, we investigate the motor representations that underlie such learning, and examine how motor memories acquired based on different contextual information interact. Using a novel three-dimensional robotic manipulandum, the 3BOT, we examined the spatial transfer of learning across various movement directions in a 3D environment, while human subjects performed reaching movements under velocity-dependent force field. The obtained pattern of generalisation suggested that the representation of dynamic learning was most likely defined in a target-based, rather than an extrinsic, coordinate system. We further examined how motor memories interact when subjects adapt to force fields applied in orthogonal dimensions. We found that, unlike opposing fields, learning two spatially orthogonal force fields led to the formation of separate motor memories, which neither interfered with nor facilitated each other. Moreover, we demonstrated a novel, more general aspect of the spontaneous recovery phenomenon using a two-dimensional force field task: when subjects learned two orthogonal force fields consecutively, in the following phase of clamped error feedback, the expression of adaptation spontaneously rotated from the direction of the second force field, towards the direction of the first force field. Finally, we examined the interaction of sensorimotor memories formed based on separate contextual information. Subjects performed reciprocating reaching and object manipulation tasks under two alternating contexts (movement directions), while we manipulated the dynamics of the task in each context separately. The results suggested that separate motor memories were formed for the dynamics of the task in different contexts, and that these motor memories interacted by sharing error signals to enhance learning. Importantly, the extent of interaction was not fixed between the context-dependent motor memories, but adaptively changed according to the task dynamics to potentially improve overall performance. Together, our experimental and theoretical results add to the understanding of mechanisms that underlie sensorimotor learning, and the way these mechanisms interact under various tasks and different dynamics.

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Kikkert, Sanne. « Sensorimotor cortex plasticity in upper-limb amputees ». Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:12104303-2f5b-4d18-bf18-d8e651a042aa.

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The current thesis was aimed at investigating how the primary sensorimotor cortex, and in particular the missing hand cortex, is affected by upper-limb amputation. This thesis further explores how activity in this region relates to phantom limb pain (PLP). As such, a series of neuroimaging experiments was designed, aimed at answering 3 main questions: 1) What happens to the neural fingerprint of a hand following its amputation? 2) What are the behavioural and neural underpinnings of PLP? 3) Can novel targets for PLP treatment be identified? By making use of ultra-high field 7 tesla fMRI and the phenomenology of phantom limb sensations, this thesis demonstrates that the topographical representation of a missing hand's individual digits is preserved in primary somatosensory cortex, even decades after arm amputation. This finding of stable topography questions the extent to which continued sensory input is necessary to maintain organisation in sensory cortex. Slowed phantom hand motor control was identified as a behavioural correlate of chronic PLP. Stronger maintained activity in the primary sensorimotor missing hand cortex was reaffirmed as a neural correlate of chronic PLP and was further associated with deteriorated phantom hand motor control. This thesis presents results challenging the maladaptive plasticity model and instead emphasising a likely relationship between persistent peripheral inputs pertaining to the missing hand representation and chronic PLP. Anodal tDCS over the primary sensorimotor missing cortex during a phantom hand movement task effectively relieved PLP with effects lasting at least one week post stimulation. In accordance with above, amputees with more PLP relief showed less activity in the primary sensorimotor cortex after brain stimulation. Importantly, tDCS-concurrent neuroimaging identified the insula and secondary somatosensory cortex as neural correlates of PLP relief and subsequent sensorimotor cortex downregulation. Together, this thesis reveals new roles of primary sensorimotor cortex following arm amputation and provides a first comprehensive overview of the neural mechanisms underlying missing hand sensations, offering novel opportunities for PLP treatment.

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Benureau, Fabien. « Self Exploration of Sensorimotor Spaces in Robots ». Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0072/document.

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La robotique développementale a entrepris, au courant des quinze dernières années,d’étudier les processus développementaux, similaires à ceux des systèmes biologiques,chez les robots. Le but est de créer des robots qui ont une enfance—qui rampent avant d’essayer de courir, qui jouent avant de travailler—et qui basent leurs décisions sur l’expérience de toute une vie, incarnés dans le monde réel.Dans ce contexte, cette thèse étudie l’exploration sensorimotrice—la découverte pour un robot de son propre corps et de son environnement proche—pendant les premiers stage du développement, lorsque qu’aucune expérience préalable du monde n’est disponible. Plus spécifiquement, cette thèse se penche sur comment générer une diversité d’effets dans un environnement inconnu. Cette approche se distingue par son absence de fonction de récompense ou de fitness définie par un expert, la rendant particulièrement apte à être intégrée sur des robots auto-suffisants.Dans une première partie, l’approche est motivée et le problème de l’exploration est formalisé, avec la définition de mesures quantitatives pour évaluer le comportement des algorithmes et d’un cadre architectural pour la création de ces derniers. Via l’examen détaillé de l’exemple d’un bras robot à multiple degrés de liberté, la thèse explore quelques unes des problématiques fondamentales que l’exploration sensorimotrice pose, comme la haute dimensionnalité et la redondance sensorimotrice. Cela est fait en particulier via la comparaison entre deux stratégies d’exploration: le babillage moteur et le babillage dirigé par les objectifs. Plusieurs algorithmes sont proposés tour à tour et leur comportement est évalué empiriquement, étudiant les interactions qui naissent avec les contraintes développementales, les démonstrations externes et les synergies motrices. De plus, parce que même des algorithmes efficaces peuvent se révéler terriblement inefficaces lorsque leurs capacités d’apprentissage ne sont pas adaptés aux caractéristiques de leur environnement, une architecture est proposée qui peut dynamiquement choisir la stratégie d’exploration la plus adaptée parmi un ensemble de stratégies. Mais même avec de bons algorithmes, l’exploration sensorimotrice reste une entreprise coûteuse—un problème important, étant donné que les robots font face à des contraintes fortes sur la quantité de données qu’ils peuvent extraire de leur environnement;chaque observation prenant un temps non-négligeable à récupérer. [...] À travers cette thèse, les contributions les plus importantes sont les descriptions algorithmiques et les résultats expérimentaux. De manière à permettre la reproduction et la réexamination sans contrainte de tous les résultats, l’ensemble du code est mis à disposition. L’exploration sensorimotrice est un mécanisme fondamental du développement des systèmes biologiques. La séparer délibérément des mécanismes d’apprentissage et l’étudier pour elle-même dans cette thèse permet d’éclairer des problèmes importants que les robots se développant seuls seront amenés à affronter
Developmental robotics has begun in the last fifteen years to study robots that havea childhood—crawling before trying to run, playing before being useful—and that are basing their decisions upon a lifelong and embodied experience of the real-world. In this context, this thesis studies sensorimotor exploration—the discovery of a robot’s own body and proximal environment—during the early developmental stages, when no prior experience of the world is available. Specifically, we investigate how to generate a diversity of effects in an unknown environment. This approach distinguishes itself by its lack of user-defined reward or fitness function, making it especially suited for integration in self-sufficient platforms. In a first part, we motivate our approach, formalize the exploration problem, define quantitative measures to assess performance, and propose an architectural framework to devise algorithms. through the extensive examination of a multi-joint arm example, we explore some of the fundamental challenges that sensorimotor exploration faces, such as high-dimensionality and sensorimotor redundancy, in particular through a comparison between motor and goal babbling exploration strategies. We propose several algorithms and empirically study their behaviour, investigating the interactions with developmental constraints, external demonstrations and biologicallyinspired motor synergies. Furthermore, because even efficient algorithms can provide disastrous performance when their learning abilities do not align with the environment’s characteristics, we propose an architecture that can dynamically discriminate among a set of exploration strategies. Even with good algorithms, sensorimotor exploration is still an expensive proposition— a problem since robots inherently face constraints on the amount of data they are able to gather; each observation takes a non-negligible time to collect. [...] Throughout this thesis, our core contributions are algorithms description and empirical results. In order to allow unrestricted examination and reproduction of all our results, the entire code is made available. Sensorimotor exploration is a fundamental developmental mechanism of biological systems. By decoupling it from learning and studying it in its own right in this thesis, we engage in an approach that casts light on important problems facing robots developing on their own

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Knafo, Steven. « Sensorimotor integration in the moving spinal cord ». Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066559/document.

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Certaines observations suggèrent que les afférences méchano-sensorielles peuvent moduler l’activité des générateurs centraux du rythme locomoteur (ou Central Pattern Generators, CPGs). Cependant, il est impossible d’explorer les circuits neuronaux sous-jacents chez l’animal en mouvement à l’aide d’enregistrements électrophysiologiques lors d’expériences de locomotion dite « fictive ». Dans cette étude, nous avons enregistré de façon sélective et non-invasive les neurones moteurs et sensoriels dans la moelle épinière pendant la locomotion active en ciblant génétiquement le senseur bioluminescent GFP-Aequorin chez la larve de poisson zèbre. En utilisant l’imagerie calcique à l’échelle des neurones individuels, nous confirmons que les signaux de bioluminescence reflètent bien le recrutement différentiel des groupes de motoneurones spinaux durant la locomotion active. La diminution importante de ces signaux chez des animaux paralysés ou des mutants immobiles démontre que le retour méchano-sensoriel augmente le recrutement des motoneurones spinaux pendant la locomotion active. En accord avec cette observation, nous montrons que les neurones méchano-sensoriels spinaux sont en effet recrutés chez les animaux en mouvement, et que leur inhibition affecte les réflexes d’échappement chez des larves nageant librement. L’ensemble de ces résultats met en lumière la contribution du retour méchano-sensoriel sur la production locomotrice et les différences qui en résultent entre les locomotions active et fictive
There is converging evidence that mechanosensory feedback modulates the activity of spinal central pattern generators underlying vertebrate locomotion. However, probing the underlying circuits in behaving animals is not possible in “fictive” locomotion electrophysiological recordings. Here, we achieve selective and non-invasive monitoring of spinal motor and sensory neurons during active locomotion by genetically targeting the bioluminescent sensor GFP-Aequorin in larval zebrafish. Using GCaMP imaging of individual neurons, we confirm that bioluminescence signals reflect the differential recruitment of motor pools during motion. Their significant reduction in paralyzed animals and immotile mutants demonstrates that mechanosensory feedback enhances the recruitment of spinal motor neurons during active locomotion. Accordingly, we show that spinal mechanosensory neurons are recruited in moving animals and that their silencing impairs escapes in freely behaving larvae. Altogether, these results shed light on the contribution of mechanosensory feedback to motor output and the resulting differences between active and fictive locomotion

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Petitet, Pierre. « Sensorimotor adaptation : mechanisms, modulation and rehabilitation potential ». Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:5935d96d-625a-4778-b42d-bb56c96d96cc.

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Adaptation is a fundamental property of the nervous system that underlies the maintenance of successful actions through flexible reconfiguration of sensorimotor processing. The primary aims of this thesis are 1) to investigate the computational and neural underpinnings of sensorimotor memory formation during prism adaptation (PA) in humans, and 2) how they interact with anodal transcranial direct current stimulation (a-tDCS) of the primary motor cortex (M1), in order to 3) improve efficacy of prism therapy for post-stroke spatial neglect. In chapter 4, we modify an influential state-space model of adaptation in order to characterize the contribution of short and long memory timescales to motor behaviour as sensorimotor after-effects (AEs) develop during PA. This enables us, in the multimodal 7 Tesla MRI experiment reported in chapter 5, to demonstrate that the level of M1 excitation:inhibition causally sets the relative contribution of long versus short memory timescales during PA, thus determining behavioural persistence of the AE at retention in young healthy adults. This finding offers a bridge between different levels of investigation by providing a biologically plausible neuro-computational model of how sensorimotor memories are formed and enhanced by a-tDCS. In chapter 6, we use the ageing motor system as a model of reduced GABAergic inhibition and show that the age-related decrease in M1 GABA explains why older adults demonstrate more persistent prism AEs. Taken together, these data indicate that the reduction in M1 GABAergic inhibition via excitatory a-tDCS during PA has the potential to enhance persistence of adaptation memory in both young and older adults. Informed by these results, we subsequently ask whether standard (multi-session) PA therapy combined with left M1 a-tDCS translates to greater and/or longer-lasting clinical improvements in post-stroke spatial neglect patients. In chapter 7, we compare the multimodal neuroimaging data of six neglect patients to normative data of age-matched controls. We show that in all patients, the lesion interrupted long-range frontoparietal connections, and we provide direct evidence for a pathological left dominance of activity within the lateral occipital cortex during deployment of bilateral visuospatial attention. In chapter 8, we present the behavioural performance of these patients throughout the two phases of the clinical study (i.e. before and after either PA + real M1 a-tDCS or PA + sham M1 atDCS). There was no clear effect of a-tDCS on the therapeutic effect of PA in these patients. The results of the studies presented in this thesis provide a novel insight into the neurocomputational mechanisms of sensorimotor memory formation and its modulation by a-tDCS in the healthy brain. Further investigation of how these mechanisms relate to therapeutic improvements following PA in certain neglect patients is needed.

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BERNARDI, NICOLO' FRANCESCO. « Mental practice : rehearsal strategies and sensorimotor outcomes ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2013. http://hdl.handle.net/10281/41783.

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Mental practice (MP) is the cognitive rehearsal of a task in the absence of overt physical movements. It has been shown that MP allows performance improvements in various tasks, but little is known about the effectiveness of different strategies of MP and about the exact sensorimotor mechanisms that underlie this improvement. Several strategies of MP are here investigated in relation to the practice outcome. In particular, in the context of music performance, it is shown that pitch imagery is strongly associated with better performance, regardless of the specific nature of the musical task. Conversely, structural/formal analysis appears to be important for music memorization, and motor imagery for fine motor control. In terms of sensorimotor outcomes of the practice, it is shown that MP results in improvements of movement velocity, movement anticipation and coarticulation. Additional experiments from force-field learning paradigm show that MP can also result in changes of somatosensory perception. Results are discussed in the context of the simulation theories of motor control.

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Mooshagian, Eric Frederick. « Behavioral and physiological examination of spatial attention in visuomotor integration ». Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1619409101&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.

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Peterson, Lauri Jo. « Resource guide for guidance counselors and teachers of students with sensory integration disorder and behavior attention problems ». Online version, 2003. http://www.uwstout.edu/lib/thesis/2003/2003petersonl.pdf.

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Menz, Mareike. « From dynamic sensorimotor interaction to conceptual action representation ». Lübeck Zentrale Hochschulbibliothek Lübeck, 2010. http://d-nb.info/1001709381/34.

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Howell, Steve R. Becker Suzanna. « Sensorimotor representations of meaning in early language acquisition / ». *McMaster only, 2004.

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44

Chong, Man-Tze Mabel. « Development of sensorimotor integration and modulation in zebrafish ». Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18784.

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Neural control of behaviour during development is a complicated orchestration of gene expression, neuronal differentiation, axonal projection, modification of intrinsic membrane properties and connectivity of neural circuits. The studies in this thesis combined genetic, molecular, and physiological assays to investigate neuromodulation, reticulospinal contribution, and neurogenic programming of the limited behavioural repertoire of developing zebrafish. Maturation of early swimming, the change from infrequent episodes of swim bursts to a sustained “beat-and-glide” pattern, was mediated by serotonergic modulation of the spinal network. Serotonergic immunoreactivity was first detected in neurons located in the ventral spinal cord at 2 days post-fertilization (dpf). A second population of serotonergic neurons was detected in the hindbrain but these remained isolated from the spinal cord in the stages studied (2-4 dpf). Serotonergic modulation of the fictive swim pattern only occurred in 4 dpf larvae, the time when “beat-and-glide” swimming emerges, but not in younger larvae. Application of serotonin did not affect properties of activity (beat-and-glide) periods, but instead reduced the periods of inactivity between activity periods. Hindbrain reticulospinal (RS) neurons displayed four types of activity patterns during simultaneous spinal motoneuron recordings of fictive swimming activity in zebrafish larvae. RS neurons generated these activity patterns even in the absence of ascending spinal input during development. The spinal CPG network, however, failed to produce rhythmic oscillations in the presence of N-methly-d-aspartate when it developed without descending RS input, indicating that the latter are necessary for development of CPG activity. In addition to swimming, zebrafish larvae also produce startle responses in reaction to potential danger, a behaviour that is missing in hi472 mutant larvae. hi472 mutation disrupt
Le contrôle neuronal du comportement durant le développement dépend de l'intégration complexe de l'expression génétique, de la différentiation neuronale, de la projection axonale, de la modification des propriétés membranaires intrinsèques et de la connectivité des circuits neuronaux. Les études décrites dans cette thèse regroupent des approches génétiques, moléculaires et physiologiques afin d'examiner la neuromodulation, la contribution du système réticulospinal et la programmation neurogène afin d'étudier le répertoire limité des comportements du poisson zébré en voie de développement. Vers la quatrième journée du développement les larves changent leur comportement de natation, ils passent d'épisodes rares et de courte durée de natation en un patron maintenu de type nage-et-glisse, ou le poisson exécute quelques fortes contractions de la queue suive d'une période de glisse. Nous avons démontré cette maturation de la natation précoce, est due à la modulation sérotoninergique du réseau spinal. L'immunoréactivité sérotoninergique est détectée initialement chez une population de neurones situés dans la moelle épinière ventrale à 2 jours post-fertilisation (jpf). Une deuxième population de neurones sérotoninergiques a été détectée dans le tronc cérébral mais celle-ci ne projette pas d'axones vers la moelle épinière aux stades étudiés (2-4 jpf). La modulation sérotoninergique du patron de natation fictive se manifeste seulement chez des alevins de 4 jpf, au moment ou la natation nage-et-glisse se déploie, mais pas chez des alevins plus jeunes. Nous avons aussi démontré que l'application de sérotonine n'a aucun effet sur les propriétés des épisodes de nage active mais par contre, résulte en une réduction de la durée périodes d'inactivité entre les épisodes de nage-et glisse. Les neurones réticulospinaux (RS) du tronc cérébral manifestent quatre types de patron d'acti

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Dinas, Sharonjit. « The body in therapy : experiences of Sensorimotor Psychotherapy ». Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/12794/.

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Background: Sensorimotor Psychotherapy is an approach for working with people who have experienced trauma (e.g. post-traumatic stress disorder [PTSD]) that is based on contemporary philosophies of embodiment and the expanse of neurobiological evidence for the effect of psychological trauma on the physical body. Thus, Sensorimotor Psychotherapy places central importance on working with the body in therapy. Method: This study explored the experiences of 10 therapists and 2 clients who have had Sensorimotor Psychotherapy, and in particular, what it was like to use the body in therapy. Semi-structured interviews were used in order to gain detailed information regarding how the using the body in therapy is experienced. Results: An inductive thematic analysis of interview transcripts identified four main themes: 1) accessing the truth through the body, 2) dilemmas of mind and body, 3) the elusiveness of words, and 4) change occurs through and within the body. 'Accessing the truth through the body' had three further subthemes: 'access', 'truth', and 'depth'. In this theme, participants described Sensorimotor Psychotherapy as being able to access the core of a problem through its use of working with the body ('access'), and that in doing so it reaches the truth of a problem or previous traumatic experience ('truth'). In order to reach and access the truth, participants described the work as having great 'depth'. 'Dilemmas of mind and body' had two further subthemes: 'the interfering mind' and ' the telling body'. In this theme, participants described the mind and body in very different ways, suggesting a dualism of mind and body. Participants described how 'the interfering mind' can distract from dealing with the real and genuine issue (accessed through the body), and that 'the telling body' was a source of genuine and important knowledge regarding a traumatic experience. The 'elusiveness of words' referred to how the participants found it difficult to describe their experiences in words, alluding to the elusiveness of words to describe the process of Sensorimotor Psychotherapy. Participants considered and discussed progress and change in Sensorimotor Psychotherapy as occurring through and within the body ('change occurs through and within the body'). Discussion: In conclusion, the participants in this study felt that by working primarily with the body, Sensorimotor Psychotherapy is able to deeply access the direct core of traumatic experience, and that parts of this process are difficult to describe in words. Furthermore, a dualism of mind and body was implicated by the participants, and change was considered to occur through and within the body. Other therapies for PTSD could consider including more focus on the body, and also consider acknowledging perceived dilemmas between the mind and body. The limitations of this study include possible sampling bias, and the verbal interview technique being unable to explore the nuanced bodily experience of the therapy. Future research should expand the sample to include those who had neutral or negative experiences of Sensorimotor Psychotherapy, and explore methods that can capture the bodily experience of the therapy considering the difficulty of the 'elusiveness of words'.

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Artz, Neil. « Sensorimotor function and dysfunction in the cervical spine ». Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544417.

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SeiÃŸ, Ellen. « Neurophysiological investigations of sensorimotor function in movement disorders ». Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422330.

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Witham, Claire. « Oscillations and corticomuscular coherence in the sensorimotor system ». Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440587.

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Thorniley, James. « Information transfer and causality in the sensorimotor loop ». Thesis, University of Sussex, 2015. http://sro.sussex.ac.uk/id/eprint/57186/.

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This thesis investigates information-theoretic tools for detecting and describing causal influences in embodied agents. It presents an analysis of philosophical and statistical approaches to causation, and in particular focuses on causal Bayes nets and transfer entropy. It argues for a novel perspective that explicitly incorporates the epistemological role of information as a tool for inference. This approach clarifies and resolves some of the known problems associated with such methods. Here it is argued, through a series of experiments, mathematical results and some philosophical accounts, that universally applicable measures of causal influence strength are unlikely to exist. Instead, the focus should be on the role that information-theoretic tools can play in inferential tests for causal relationships in embodied agents particularly, and dynamical systems in general. This thesis details how these two approaches differ. Following directly from these arguments, the thesis proposes a concept of “hidden” information transfer to describe situations where causal influences passing through a chain of variables may be more easily detected at the end-points than at intermediate nodes. This is described using theoretical examples, and also appears in the information dynamics of computer-simulated and real robots developed herein. Practical examples include some minimal models of agent-environment systems, but also a novel complete system for generating locomotion gait patterns using a biologically-inspired decentralized architecture on a walking robotic hexapod.

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Berthold, Oswald. « Robotic self-exploration and acquisition of sensorimotor skills ». Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21480.

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Die Interaktion zwischen Maschinen und ihrer Umgebung sollte zuverlässig, sicher und ökologisch adequat sein. Um das in komplexen Szenarien langfristig zu gewährleisten, wird eine Theorie adaptiven Verhaltens benötigt. In der Entwicklungsrobotik und verkörperten künstlichen Intelligenz wird Verhalten als emergentes Phänomen auf der fortlaufenden dynamischen Interaktion zwischen Agent, Körper und Umgebung betrachtet. Die Arbeit untersucht Roboter, die in der Lage sind, schnell und selbständig einfache Bewegungen auf Grundlage sensomotorischer Information zu erlernen. Das langfristige Ziel dabei ist die Wiederverwendung gelernter Fertigkeiten in späteren Lernprozessen um damit ein komplexes Interaktionsrepertoire mit der Welt entstehen zu lassen, das durch Entwicklungsprozesse vollständig und fortwährend adaptiv in der sensomotorischen Erfahrung verankert ist. Unter Verwendung von Methoden des maschinellen Lernens, der Neurowissenschaft, Statistik und Physik wird die Frage in die Komponenten Repräsentation, Exploration, und Lernen zerlegt. Es wird ein Gefüge für die systematische Variation und Evaluation von Modellen errichtet. Das vorgeschlagene Rahmenwerk behandelt die prozedurale Erzeugung von Hypothesen als Flussgraphen über einer festen Menge von Funktionsbausteinen, was die Modellsuche durch nahtlose Anbindung über simulierte und physikalische Systeme hinweg ermöglicht. Ein Schwerpunkt der Arbeit liegt auf dem kausalen Fussabdruck des Agenten in der sensomotorischen Zeit. Dahingehend wird ein probabilistisches graphisches Modell vorgeschlagen um Infor- mationsflussnetzwerke in sensomotorischen Daten zu repräsentieren. Das Modell wird durch einen auf informationtheoretischen Grössen basierenden Lernalgorithmus ergänzt. Es wird ein allgemeines Modell für Entwicklungslernen auf Basis von Echtzeit-Vorhersagelernen präsentiert und anhand dreier Variationen näher besprochen.
The interaction of machines with their environment should be reliable, safe, and ecologically adequate. To ensure this over long-term complex scenarios, a theory of adaptive behavior is needed. In developmental robotics, and embodied artificial intelligence behavior is regarded as a phenomenon that emerges from an ongoing dynamic interaction between entities called agent, body, and environment. The thesis investigates robots that are able to learn rapidly and on their own, how to do primitive motions, using sensorimotor information. The long-term goal is to reuse acquired skills when learning other motions in the future, and thereby grow a complex repertoire of possible interactions with the world, that is fully grounded in, and continually adapted to sensorimotor experience through developmental processes. Using methods from machine learning, neuroscience, statistics, and physics, the question is decomposed into the relationship of representation, exploration, and learning. A framework is provided for systematic variation and evaluation of models. The proposed framework considers procedural generation of hypotheses as scientific workflows using a fixed set of functional building blocks, and allows to search for models by seamless evaluation in simulation and real world experiments. Additional contributions of the thesis are related to the agent's causal footprint in sensorimotor time. A probabilistic graphical model is provided, along with an information-theoretic learning algorithm, to discover networks of information flow in sensorimotor data. A generic developmental model, based on real time prediction learning, is presented and discussed on the basis of three different algorithmic variations.

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