Enabling the future. Prospective action representations in the human parieto-frontal motor planning system

One of the primary functions of the central nervous system is to make the body move. Whenever we try to find a mating partner, hunt for food or avoid becoming it ourselves, we need to move. No wonder then, that how does a voluntary movement emerge from brain activity has been one of the most extensively studied problems in neuroscience. But, even despite the research effort, the exact mechanisms are still far from understood. In my dissertation I scrutinize a portion of the complex system responsible for transforming thoughts into actions. Specifically, I focus on the interplay between the cognitive and the motor components of action plans and their representations in posterior parietal and premotor cortex. In the first chapter I start by bringing up the psychological theories of how are the mental representations related to motor actions. Next, I briefly review the current state of knowledge about neural correlates of action planning in the primate brain. I concentrate on hand movements as they pose the major challenge in understanding the motor system, being the most complex type of actions the human body is capable of. After having built this general background, I present my own work, where I try to answer three questions about parieto-frontal processing in action planning: 1) Does the brain visually simulate action effects in prior to action execution? 2) Are the reach trajectory plans organized along one, common neural pathway? 3) Are working memory processes modulated by effector preparation? In the final part of the dissertation I summarize my findings and briefly reflect upon the tangled relationship between the ability to represent and realize ideas, and how it might have shaped the evolution of other remarkable features of the human mind

Virtual reality for safe testing and development in collaborative robotics: challenges and perspectives

Collaborative robots (cobots) could help humans in tasks that are mundane, dangerous or where direct human contact carries risk. Yet, the collaboration between humans and robots is severely limited by the aspects of the safety and comfort of human operators. In this paper, we outline the use of extended reality (XR) as a way to test and develop collaboration with robots. We focus on virtual reality (VR) in simulating collaboration scenarios and the use of cobot digital twins. This is specifically useful in situations that are difficult or even impossible to safely test in real life, such as dangerous scenarios. We describe using XR simulations as a means to evaluate collaboration with robots without putting humans at harm. We show how an XR setting enables combining human behavioral data, subjective self-reports, and biosignals signifying human comfort, stress and cognitive load during collaboration. Several works demonstrate XR can be used to train human operators and provide them with augmented reality (AR) interfaces to enhance their performance with robots. We also provide a first attempt at what could become the basis for a human–robot collaboration testing framework, specifically for designing and testing factors affecting human–robot collaboration. The use of XR has the potential to change the way we design and test cobots, and train cobot operators, in a range of applications: from industry, through healthcare, to space operations.info:eu-repo/semantics/publishedVersio

Beware ‘persuasive communication devices’ when writing and reading scientific articles

Authors rely on a range of devices and techniques to attract and maintain the interest of readers, and to convince them of the merits of the author’s point of view. However, when writing a scientific article, authors must use these ‘persuasive communication devices’ carefully. In particular, they must be explicit about the limitations of their work, avoid obfuscation, and resist the temptation to oversell their results. Here we discuss a list of persuasive communication devices and we encourage authors, as well as reviewers and editors, to think carefully about their use

Distinct contributions of human posterior parietal and dorsal premotor cortex to reach trajectory planning

Abstract Goal-directed hand movements are usually directed straight at the target, e.g. when swatting a fly. Their paths can also become quite complex, when drawing or avoiding obstacles. Studies on movement planning have largely neglected the latter movement type and the question of whether it is the same neural machinery that is planning such complex hand trajectories as well as straight, vector-like movements. Using time-resolved fMRI during delayed response tasks we examined planning activity in human superior parietal lobule (SPL) and dorsal premotor cortex (PMd). We show that the recruitment of both areas in trajectory planning differs significantly: PMd represented both straight and complex hand trajectories while SPL only those that led straight to the target. This suggests that while posterior parietal cortex only provides representations for simple, straight reaches, the complex and computationally demanding reach planning necessarily involves dorsal premotor cortex. Our findings yield new insights into the organization of cerebro-cortical strategies of forming reach trajectory plans

Human posterior parietal and dorsal premotor cortex encode the visual properties of an upcoming action.

Behavioral studies show that motor actions are planned by adapting motor programs to produce desired visual consequences. Does this mean that the brain plans these visual consequences independent of the motor actions required to obtain them? Here we addressed this question by investigating planning-related fMRI activity in human posterior parietal (PPC) and dorsal premotor (PMd) cortex. By manipulating visual movement of a virtual end-effector controlled via button presses we could dissociate motor actions from their sensory outcome. A clear representation of the visual consequences was visible in both PPC and PMd activity during early planning stages. Our findings suggest that in both PPC and PMd action plans are initially represented on the basis of the desired sensory outcomes while later activity shifts towards representing motor programs

Remember how to use it: Effector-dependent modulation of spatial working memory activity in posterior parietal cortex

Working memory (WM) is the key process linking perception to action. Several lines of research have, accordingly, highlighted WM's engagement in sensori-motor associations between retrospective stimuli and future behavior. Using human fMRI we investigated whether prior information about the effector used to respond in a WM task would have an impact on the way the same sensory stimulus is maintained in memory despite a behavioral response could not be readily planned. We focused on WM-related activity in posterior parietal cortex during the maintenance of spatial items for a subsequent match-to-sample comparison, which was reported either with a verbal or with a manual response. We expected WM activity to be higher for manual response trials, because of posterior parietal cortex's engagement in both spatial WM and hand movement preparation. Increased fMRI activity for manual response trials in bilateral anterior intraparietal sulcus confirmed our expectations. These results imply that the maintenance of sensory material in WM is optimized for motor context, i.e. for the effector that will be relevant in the upcoming behavioral responses

Tool heads prime saccades

Abstract Tools are wielded by their handles, but a lot of information about their function comes from their heads (the action-ends). Here we investigated whether eye saccadic movements are primed by tool handles, or whether they are primed by tool heads. We measured human saccadic reaction times while subjects were performing an attentional task. We found that saccades were executed quicker when performed to the side congruent with the tool head, even though “toolness” was irrelevant for the task. Our results show that heads are automatically processed by the visual system to orient eye movements, indicating that eyes are attracted by functional parts of manipulable objects and by the characteristic information these parts convey

Optimistic Youth: Young Adults Predicted a Faster Decrease in Risk during COVID-19 Emergency State in Portugal

Perception of risk is known to change throughout the lifespan. Previous studies showed that younger adults are more prone to risk behaviours than older adults. Do these age-related differences influence risk perception during a pandemic crisis? Here, we investigated how age influenced predicted risk during the COVID-19 emergency state in Portugal. We show that time-projected estimations (e.g., appraisals based on ‘now’ vs. ‘in two weeks’ time’, or ‘in four weeks’ time’) of both risk behaviour and importance of transmission prevention decrease over time. Importantly, projected risk decreased more steeply for younger than older adults. Our findings suggest that younger adults have a different perception of epidemic-related risk than older adults. This seems to support the view that public health policy making during epidemics should differentially target younger adults