“Biological Geometry Perception”: Visual Discrimination of Eccentricity Is Related to Individual Motor Preferences

In the continuum between a stroke and a circle including all possible ellipses, some eccentricities seem more “biologically preferred” than others by the motor system, probably because they imply less demanding coordination patterns. Based on the idea that biological motion perception relies on knowledge of the laws that govern the motor system, we investigated whether motorically preferential and non-preferential eccentricities are visually discriminated differently. In contrast with previous studies that were interested in the effect of kinematic/time features of movements on their visual perception, we focused on geometric/spatial features, and therefore used a static visual display.In a dual-task paradigm, participants visually discriminated 13 static ellipses of various eccentricities while performing a finger-thumb opposition sequence with either the dominant or the non-dominant hand. Our assumption was that because the movements used to trace ellipses are strongly lateralized, a motor task performed with the dominant hand should affect the simultaneous visual discrimination more strongly. We found that visual discrimination was not affected when the motor task was performed by the non-dominant hand. Conversely, it was impaired when the motor task was performed with the dominant hand, but only for the ellipses that we defined as preferred by the motor system, based on an assessment of individual preferences during an independent graphomotor task.Visual discrimination of ellipses depends on the state of the motor neural networks controlling the dominant hand, but only when their eccentricity is “biologically preferred”. Importantly, this effect emerges on the basis of a static display, suggesting that what we call “biological geometry”, i.e., geometric features resulting from preferential movements is relevant information for the visual processing of bidimensional shapes

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Is Developmental Coordination Disorder a Dysconnection Syndrome?

Purpose of Review Classical view of disconnection refers to damage in white matter connections leading to behavioral deficits on sensorimotor and cognitive tasks in brain-injured patients. A more recent conception refers to dysconnection, that means abnormal connectivity between brain regions, as found in psychiatric, neurodegenerative, and neurodevelopmental disorders. The present paper aims to explore the hypothesis that Developmental Coordination Disorder (DCD) presents a set of neural, behavioral, and cognitive signs that suggest a dysconnection syndrome. Recent Findings Current literature on DCD using behavioral and neuroimaging measures suggests several dysconnections (1) between hemispheres, (2) within hemispheres, (3) within the cortico-subcortical loops, and (4) in the cortico-spinal tract. Summary Brain dysconnections could explain the diversity of behavioral and cognitive deficits in DCD such as deficits in motor control during inter-limb rhythmic coordination and unimanual movements, deficits in motor imagery, planning and execution, and learning difficulties. Future studies using behavioral and neuroimaging measures should endeavor to map the relationship between putative dysconnections and behavioral and cognitive deficits in DCD. It will also be necessary to identify DCD-specific dysconnections compared with other neurodevelopmental disorders

Behavioural and cerebral asymmetries of mirror movements are specific to rhythmic task and related to higher attentional and executive control

International audienc

Regular rhythmic and audio-visual stimulations enhance procedural learning of a perceptual-motor sequence in healthy adults: A pilot study

International audienceProcedural learning is essential for the effortless execution of many everyday life activities. However, little is known about the conditions influencing the acquisition of procedural skills. The literature suggests that sensory environment may influence the acquisition of perceptual-motor sequences, as tested by a Serial Reaction Time Task. In the current study, we investigated the effects of auditory stimulations on procedural learning of a visuo-motor sequence. Given that the literature shows that regular rhythmic auditory rhythm and multisensory stimulations improve motor speed, we expected to improve procedural learning (reaction times and errors) with repeated practice with auditory stimulations presented either simultaneously with visual stimulations or with a regular tempo, compared to control conditions (e.g., with irregular tempo). Our results suggest that both congruent audiovisual stimulations and regular rhythmic auditory stimulations promote procedural perceptual-motor learning. On the contrary, auditory stimulations with irregular or very quick tempo alter learning. We discuss how regular rhythmic multisensory stimulations may improve procedural learning with respect of a multisensory rhythmic integration process

Approche dynamique de la mémoire motrice humaine

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Proactive transfer of learning depends on the evolution of prior learned task in memory

The aim of the present study was to investigate the processes underlying the proactive interference effect using bimanual coordination. Our rationale was that interference would only occur when the prior learned A coordination pattern enters in competition with the required subsequent B pattern. We hypothesized that competition would arise only if the A pattern persists in memory before introducing the B pattern. In the experimental group, both A and B patterns were practiced and recalled, whereas in the control group only the B pattern was practiced and recalled. In Experiment 1, which involved initially bistable participants, the persistence of the A pattern led to interference, while, surprisingly, the A pattern forgetting entailed facilitation. In Experiment 2, which involved initially tristable participants, no such transfer effect was found. The apparently contradictory results can be interpreted coherently in the light of dynamical principles of learning

The role of motor memory in action selection and procedural learning: insights from children with typical and atypical development

International audienceMotor memory is the process by which humans can adopt both persistent and flexible motor behaviors. Persistence and flexibility can be assessed through the examination of the cooperation/competition between new and old motor routines in the motor memory repertoire. Two paradigms seem to be particularly relevant to examine this competition/cooperation. First, a manual search task for hidden objects, namely the C-not-B task, which allows examining how a motor routine may influence the selection of action in toddlers. The second paradigm is procedural learning, and more precisely the consolidation stage, which allows assessing how a previously learnt motor routine becomes resistant to subsequent programming or learning of a new competitive motor routine. The present article defends the idea that results of both paradigms give precious information to understand the evolution of motor routines in healthy children. Moreover, these findings echo some clinical observations in developmental neuropsychology, particularly in children with Developmental Coordination Disorder. Such studies suggest that the level of equilibrium between persistence and flexibility of motor routines is an index of the maturity of the motor system

The Role of Stability in the Dynamics of Learning, Memorizing, and Forgetting New Coordination Patterns

International audienceAccording to a dynamic theory of learning, how a new memory is formed depends on the stability of the nearest preexisting memories. To predict retention after practice, the authors analyzed how 15 participants memorized 2 bimanual coordination patterns (45° or 135° relative phase). The authors assessed (a) how participants memorized the required patterns with learning and (b) how the associated memory layout evolved. Results showed that a practiced 45° pattern near a very stable memory (0°) persisted, whereas a 135° pattern near a less stable memory (180°) was forgotten. Those findings corroborate the proposition that retention of coordination patterns depends on the stability of the extant motor memories. The authors discuss that proposal in terms of the coevolution of accuracy and stability with learning to predict persistence of required or false memories

What neurological diseases tell us about procedural perceptual-motor learning?: A systematic review of the literature

International audienceIntroduction : Procedural perceptual-motor learning of sequences (PPMLS) provides perceptual-motor skills in many activities of daily living. Based on behavioral and neuroimaging results, theoretical models of PPMLS postulate that the cortico-striatal loop, the cortico-cerebellar loop and the hippocampus are specifically involved in the early stage of PPMLS while the cortico-striatal loop would be specifically involved in the late stage of PPMLS. Hence, current models predict that the early stage of PPMLS should be impaired in Parkinson's disease (PD: lesion of the cortico-striatal loop), in cerebellar disease (CD: lesion of the cortico-cerebellar loop) and in Alzheimer's disease (AD: lesion of the hippocampus), whereas the late stage of PPMLS should be specifically impaired in PD. Objective : The aim of the study is (1) to draw a complete picture of experimental results on PPMLS in PD, CD and AD (2) to understand heterogeneity of results as regard to participant and task characteristics. Method : This review is based on the guideline proposed by the PRISMA statement. Results : Our review reveals (1) that the experimental results clarify the theoretical models and (2) that the impairment of PPMLS depends on both the personal characteristics of the participants and the characteristics of the task to-be-learnt rather than on the disease itself. Conclusion : Our results highlight that these characteristics should be more carefully considered to understand the heterogeneity of results across studies on PPMLS and the effects of rehabilitation programs