The combined effects of motor and social goals on the kinematics of object-directed motor action

Voluntary actions towards manipulable objects are usually performed with a particular motor goal (i.e., a task-specific object-target-effector interaction) and in a particular social context (i.e., who would benefit from these actions), but the mutual influence of these two constraints has not yet been properly studied. For this purpose, we asked participants to grasp an object and place it on either a small or large target in relation to Fitts' law (motor goal). This first action prepared them for a second grasp-to-place action which was performed under temporal constraints, either by the participants themselves or by a confederate (social goal). Kinematic analysis of the first preparatory grasp-to-place action showed that, while deceleration time was impacted by the motor goal, peak velocity was influenced by the social goal. Movement duration and trajectory height were modulated by both goals, the effect of the social goal being attenuated by the effect of the motor goal. Overall, these results suggest that both motor and social constraints influence the characteristics of object-oriented actions, with effects that combine in a hierarchical way.- This work was funded by the French National Research Agency (ANR-11-EQPX-0023) and also supported by European funds through the program FEDER SCV-IrDIVE. MFG was financed by the Region Hauts-de-France and the University of Lille. We are grateful to Anya Attou for her contribution to the data collection, Laurent Ott for his support in the computer programming of the study and Celia Moreira (mathematical researcher at FCUP-CMUP, University of Porto) for her helpful suggestions for statistical analysis

Subcortical contributions to the sense of body ownership

The sense of body ownership (i.e., the feeling that our body or its parts belong to us) plays a key role in bodily self-consciousness and is believed to stem from multisensory integration. The development of experimental paradigms that allow the controlled manipulation of body ownership in laboratory settings, such as the rubber hand illusion, provide an effective tool to investigate the malleability of the sense of body ownership and the boundaries distinguishing self and other. Neuroimaging studies on body ownership converge on the involvement of several cortical regions, including the premotor cortex and posterior parietal cortex. However, relatively less attention has been paid to subcortical structures that may also contribute to body ownership perception, such as the cerebellum and putamen. Here, on the basis of neuroimaging and neuropsychological observations, we provide an overview of relevant subcortical regions and consider their potential role in generating and maintaining a sense of ownership over the body. We also suggest novel avenues for future research targeting the role of subcortical regions in making sense of the body as our own

Learning of Action and Perception in Walking

Motor adaptation is a trial and error process that allows us to adjust our movements in response to changes in our environment and our body. It is thought that this process recalibrates a forward model (potentially housed in the cerebellum), which predicts the sensory consequences of our motor actions. This has been typically thought to be a recalibration of the motor system. However, recent evidence in reaching adaptation studies has shown that there are also changes to sensory perception, specifically kinesthesia, that accompany motor changes. This dissertation examines which sensory perceptual changes occur during walking adaptation, the role of the cerebellum in these changes and how we can modulate them by changing the way individuals learn. First, we studied changes in lower limb speed, position and force perception after subjects learned a new locomotor pattern on a split-belt treadmill. For each psychophysical experiment, we compared groups of healthy individuals who either learned a new pattern (experienced a 3:1 split-belt perturbation) or did not (walked at a tied fast speed). We found that of these three parameters, walking speed perception was the only one that changed significantly after learning a new walking pattern. We then went on to test whether this change to speed perception was a general one by testing generalization to a backwards walking direction. As expected, we found there was no transfer to the backwards direction in either the motor or speed perception domains. This suggests that the perceptual change may be specific to the context of walking and stem from the discrepancy between expected and actual leg motions following split-belt adaptation. In our second study, we used the previous protocol for testing changes in speed perception in individuals with cerebellar ataxia. We compared this to healthy age-matched subjects. Surprisingly, we found that patients had preserved temporal components of motor adaptation, compared to healthy controls. We also found that in addition to spatial motor deficits, which we have previously shown, ataxia patients also showed aftereffect deficits in walking speed perception. These results implicate the involvement of the cerebellum in the recalibration of both motor and walking speed perception during split belt adaptation. In our final study, we studied how we could modulate motor and speed perception aftereffects by changing the way subjects learned on the split-belt treadmill. We carried this out by applying different perturbations (abrupt versus gradual) to separate groups of healthy individuals. Surprisingly, we found that despite the fact that groups learned the same amount in the motor domain, the group that learned from a gradual perturbation showed much larger aftereffects in speed perception. This suggests involvement of another mechanism, perhaps one that deals with the explicit nature of errors, which can differentially affect the recalibration of sensory perception associated with learning a new walking pattern. Taken together, these results suggest that walking speed is a salient perception that changes with split-belt adaptation, that it is affected by damage to the cerebellum and it can be changed depending on the size of errors experienced during learning

The effect of training for field-independence on formal operations : The consequences for general ability and the effectiveness of developing an associated meta-cognitive language in combination with the training procedures

After conducting a number of pilot studies pre- and post-tests were given to three experimental classes of 11 to 13 year old early adolescents, one taken by Collings, and the two others by an inexperienced teacher. With one class the latter used materials designed to develop Field-independence only, with the other the teacher followed a similar pattern to Collings who incorporated a meta-cognitive aspect by encouraging students to analyse their own thinking strategies and to 'bridge' between the Field-independence lessons and the contexts of science. There were two control classes, and the overall period of the intervention was one school year with about 20% of the science teaching time used for the intervention. The tests used were the Group embedded Figures Test (GHFT) for Field-independence, and Volume and Heaviness (SRTII), NFER (1979) for Piagetian operations. In the pre- post-test Comparisons between experimental and Control groups all the differences between the differences were statistically significant. Collings' own class showed an effect-size of 1.53 σ on GBFT over the controls, and 0.92 σ on SRTII. The inexperienced teacher's class with Field-independence training only, showed an effect-size of 1.09 σ on GHFT and 0.36 on SRTII whereas his class with meta cognition added showed an effect-size of 1.13 σ on GEFT, and 0.63 σ on SRTII. There was no statistical difference between the 1.09 and 1.13 σ on GEFT and this inferred that the Field-independence materials were fairly robust to teacher effects. The difference between 0.36 and 0.68 σ on SRTII was significantly different, and this was interpreted as showing that the meta-cognitive aspect assisted transfer of training to Formal Operations

Mental Imagery in Humanoid Robots

Mental imagery presents humans with the opportunity to predict prospective happenings based on own intended actions, to reminisce occurrences from the past and reproduce the perceptual experience. This cognitive capability is mandatory for human survival in this folding and changing world. By means of internal representation, mental imagery offers other cognitive functions (e.g., decision making, planning) the possibility to assess information on objects or events that are not being perceived. Furthermore, there is evidence to suggest that humans are able to employ this ability in the early stages of infancy. Although materialisation of humanoid robot employment in the future appears to be promising, comprehensive research on mental imagery in these robots is lacking. Working within a human environment required more than a set of pre-programmed actions. This thesis aims to investigate the use of mental imagery in humanoid robots, which could be used to serve the demands of their cognitive skills as in humans. Based on empirical data and neuro-imaging studies on mental imagery, the thesis proposes a novel neurorobotic framework which proposes to facilitate humanoid robots to exploit mental imagery. Through conduction of a series of experiments on mental rotation and tool use, the results from this study confirm this potential. Chapters 5 and 6 detail experiments on mental rotation that investigate a bio-constrained neural network framework accounting for mental rotation processes. They are based on neural mechanisms involving not only visual imagery, but also affordance encoding, motor simulation, and the anticipation of the visual consequences of actions. The proposed model is in agreement with the theoretical and empirical research on mental rotation. The models were validated with both a simulated and physical humanoid robot (iCub), engaged in solving a typical mental rotation task. The results show that the model is able to solve a typical mental rotation task and in agreement with data from psychology experiments, they also show response times linearly dependent on the angular disparity between the objects. Furthermore, the experiments in chapter 6 propose a novel neurorobotic model that has a macro-architecture constrained by knowledge on brain, which encompasses a rather general mental rotation mechanism and incorporates a biologically plausible decision making mechanism. The new model is tested within the humanoid robot iCub in tasks requiring to mentally rotate 2D geometrical images appearing on a computer screen. The results show that the robot has an enhanced capacity to generalize mental rotation of new objects and shows the possible effects of overt movements of the wrist on mental rotation. These results indicate that the model represents a further step in the identification of the embodied neural mechanisms that might underlie mental rotation in humans and might also give hints to enhance robots' planning capabilities. In Chapter 7, the primary purpose for conducting the experiment on tool use development through computational modelling refers to the demonstration that developmental characteristics of tool use identified in human infants can be attributed to intrinsic motivations. Through the processes of sensorimotor learning and rewarding mechanisms, intrinsic motivations play a key role as a driving force that drives infants to exhibit exploratory behaviours, i.e., play. Sensorimotor learning permits an emergence of other cognitive functions, i.e., affordances, mental imagery and problem-solving. Two hypotheses on tool use development are also conducted thoroughly. Secondly, the experiment tests two candidate mechanisms that might underlie an ability to use a tool in infants: overt movements and mental imagery. By means of reinforcement learning and sensorimotor learning, knowledge of how to use a tool might emerge through random movements or trial-and-error which might reveal a solution (sequence of actions) of solving a given tool use task accidentally. On the other hand, mental imagery was used to replace the outcome of overt movements in the processes of self-determined rewards. Instead of determining a reward from physical interactions, mental imagery allows the robots to evaluate a consequence of actions, in mind, before performing movements to solve a given tool use task. Therefore, collectively, the case of mental imagery in humanoid robots was systematically addressed by means of a number of neurorobotic models and, furthermore, two categories of spatial problem solving tasks: mental rotation and tool use. Mental rotation evidently involves the employment of mental imagery and this thesis confirms the potential for its exploitation by humanoid robots. Additionally, the studies on tool use demonstrate that the key components assumed and included in the experiments on mental rotation, namely affordances and mental imagery, can be acquired by robots through the processes of sensorimotor learning.Ministry of Science and Technology, the Thai Governmen

Computer-supported movement guidance: investigating visual/visuotactile guidance and informing the design of vibrotactile body-worn interfaces

This dissertation explores the use of interactive systems to support movement guidance, with applications in various fields such as sports, dance, physiotherapy, and immersive sketching. The research focuses on visual, haptic, and visuohaptic approaches and aims to overcome the limitations of traditional guidance methods, such as dependence on an expert and high costs for the novice. The main contributions of the thesis are (1) an evaluation of the suitability of various types of displays and visualizations of the human body for posture guidance, (2) an investigation into the influence of different viewpoints/perspectives, the addition of haptic feedback, and various movement properties on movement guidance in virtual environments, (3) an investigation into the effectiveness of visuotactile guidance for hand movements in a virtual environment, (4) two in-depth studies of haptic perception on the body to inform the design of wearable and handheld interfaces that leverage tactile output technologies, and (5) an investigation into new interaction techniques for tactile guidance of arm movements. The results of this research advance the state of the art in the field, provide design and implementation insights, and pave the way for new investigations in computer-supported movement guidance