Upright Posture: A Singular Condition Stabilizing Sensorimotor Coordination.

It has long been hypothesized that the nervous system uses the direction of gravity to align the various sensory systems when interacting with the external world. In line with this hypothesis, systematic drift in hand-path orientation was recently observed during targeted arm motions performed with eyes closed in weightlessness or, on Earth, for longitudinal movements in a supine posture. No such drift was observed in upright posture on Earth.

Understanding adolescent mental health symptom progression in school-based settings: The Substance Use and Risk Factors (SURF) longitudinal survey.

The adolescent mental health crisis has prompted a need for an improved understanding of developmental trajectories of psychopathology to promote understanding of risk and protective factors and bolster prevention and intervention efforts. The present study describes the Substance Use and Risk Factors Survey, a universal screener of mental health, substance use, and school and contextual factors administered in public middle and high schools in Massachusetts (₂₀₂₀ = 3,522, ₂₀₂₁ = 6,484, ₂₀₂₂ = 23,915). Using a seven-question linking code approach, a subset of students were longitudinally linked across administrations ( = 563, 58% female sex, 30.

A Singular Theory of Sensorimotor Coordination: On Targeted Motions in Space.

Gravity has long been purported to serve a unique role in sensorimotor coordination, but the specific mechanisms underlying gravity-based visuomotor realignment remain elusive. In this study, astronauts (nine males, two females) performed targeted hand movements with eyes open or closed, both on the ground and in weightlessness. Measurements revealed systematic drift in hand-path orientation seen only when eyes were closed and only in very specific conditions with respect to gravity.

Modality-Independent Effect of Gravity in Shaping the Internal Representation of 3D Space for Visual and Haptic Object Perception.

Visual and haptic perceptions of 3D shape are plagued by distortions, which are influenced by nonvisual factors, such as gravitational vestibular signals. Whether gravity acts directly on the visual or haptic systems or at a higher, modality-independent level of information processing remains unknown. To test these hypotheses, we examined visual and haptic 3D shape perception by asking male and female human subjects to perform a "squaring" task in upright and supine postures and in microgravity.

American High School Students' Knowledge and Beliefs about Parenting and Early Childhood Development.

Income-based achievement gaps in cognitive skills are already large when children enter Kindergarten. By adopting a preventative approach that considers the efficacy of providing parenting knowledge to individuals before they become parents while they are still in secondary school, we may be able to reduce achievement gaps. In this study, we examined adolescents' knowledge and understanding of parenting and child development by creating and validating the Adolescent Parenting Knowledge and Attitudes Survey and administering it to over 1000 US high school students.

Real-Time Control of a Multi-Degree-of-Freedom Mirror Myoelectric Interface During Functional Task Training.

Motor learning mediated by motor training has in the past been explored for rehabilitation. Myoelectric interfaces together with exoskeletons allow patients to receive real-time feedback about their muscle activity. However, the number of degrees of freedom that can be simultaneously controlled is limited, which hinders the training of functional tasks and the effectiveness of the rehabilitation therapy.

How Tilting the Head Interferes With Eye-Hand Coordination: The Role of Gravity in Visuo-Proprioceptive, Cross-Modal Sensory Transformations.

To correctly position the hand with respect to the spatial location and orientation of an object to be reached/grasped, visual information about the target and proprioceptive information from the hand must be compared. Since visual and proprioceptive sensory modalities are inherently encoded in a retinal and musculo-skeletal reference frame, respectively, this comparison requires cross-modal sensory transformations. Previous studies have shown that lateral tilts of the head interfere with the visuo-proprioceptive transformations.

Persistent deterioration of visuospatial performance in spaceflight.

Although human adaptation to spaceflight has been studied for decades, little is known about its long-term effects on brain and behavior. The present study investigated visuospatial performance and associated electrophysiological responses in astronauts before, during, and after an approximately half-year long mission to the International Space Station. Here we report findings demonstrating that cognitive performance can suffer marked decrements during spaceflight.

The visual encoding of purely proprioceptive intermanual tasks is due to the need of transforming joint signals, not to their interhemispheric transfer.

To perform goal-oriented hand movement, humans combine multiple sensory signals (e.g., vision and proprioception) that can be encoded in various reference frames (body centered and/or exo-centered).

A strategy of faster movements used by elderly humans to lift objects of increasing weight in ecological context.

It is not known whether, during the course of aging, changes occur in the motor strategies used by the CNS for lifting objects of different weights. Here, we analyzed the kinematics of object-lifting in two different healthy groups (young and elderly people) plus one well-known deafferented patient (GL). The task was to reach and lift onto a shelf an opaque cylindrical object with changing weight.

Perception of Affordance during Short-Term Exposure to Weightlessness in Parabolic Flight.

We investigated the role of the visual eye-height (VEH) in the perception of affordance during short-term exposure to weightlessness. Sixteen participants were tested during parabolic flight (0g) and on the ground (1g). Participants looked at a laptop showing a room in which a doorway-like aperture was presented.

Perception of affordances during long-term exposure to weightlessness in the International Space station.

On Earth, visual eye height (VEH)--the distance from the observer's line of gaze to the ground in the visual scene--constitutes an effective cue in perceiving affordance such as the passability through apertures, based on the assumption that one's feet are on the ground. In the present study, we questioned whether an observer continues to use VEH to estimate the width of apertures during long-term exposure to weightlessness, where contact with the floor is not required. Ten astronauts were tested in preflight, inflight in the International Space Station, and postflight sessions.

Physiological modules for generating discrete and rhythmic movements: component analysis of EMG signals.

A central question in Neuroscience is that of how the nervous system generates the spatiotemporal commands needed to realize complex gestures, such as handwriting. A key postulate is that the central nervous system (CNS) builds up complex movements from a set of simpler motor primitives or control modules. In this study we examined the control modules underlying the generation of muscle activations when performing different types of movement: discrete, point-to-point movements in eight different directions and continuous figure-eight movements in both the normal, upright orientation and rotated 90°.

Physiological modules for generating discrete and rhythmic movements: action identification by a dynamic recurrent neural network.

In this study we employed a dynamic recurrent neural network (DRNN) in a novel fashion to reveal characteristics of control modules underlying the generation of muscle activations when drawing figures with the outstretched arm. We asked healthy human subjects to perform four different figure-eight movements in each of two workspaces (frontal plane and sagittal plane). We then trained a DRNN to predict the movement of the wrist from information in the EMG signals from seven different muscles.

Relative quantity judgments between discrete spatial arrays by chimpanzees (Pan troglodytes) and New Zealand robins (Petroica longipes).

Quantity discrimination for items spread across spatial arrays was investigated in chimpanzees (Pan troglodytes) and North Island New Zealand robins (Petroica longipes), with the aim of examining the role of spatial separation on the ability of these 2 species to sum and compare nonvisible quantities which are both temporally and spatially separated, and to assess the likely mechanism supporting such summation performance. Birds and chimpanzees compared 2 sets of discrete quantities of items that differed in number. Six quantity comparisons were presented to both species: 1v2, 1v3, 1v5, 2v3, 2v4, and 2v5.

A modular theory of multisensory integration for motor control.

To control targeted movements, such as reaching to grasp an object or hammering a nail, the brain can use divers sources of sensory information, such as vision and proprioception. Although a variety of studies have shown that sensory signals are optimally combined according to principles of maximum likelihood, increasing evidence indicates that the CNS does not compute a single, optimal estimation of the target's position to be compared with a single optimal estimation of the hand. Rather, it employs a more modular approach in which the overall behavior is built by computing multiple concurrent comparisons carried out simultaneously in a number of different reference frames.

Gravity influences top-down signals in visual processing.

Visual perception is not only based on incoming visual signals but also on information about a multimodal reference frame that incorporates vestibulo-proprioceptive input and motor signals. In addition, top-down modulation of visual processing has previously been demonstrated during cognitive operations including selective attention and working memory tasks. In the absence of a stable gravitational reference, the updating of salient stimuli becomes crucial for successful visuo-spatial behavior by humans in weightlessness.

Task dependency of grip stiffness--a study of human grip force and grip stiffness dependency during two different tasks with same grip forces.

It is widely known that the pinch-grip forces of the human hand are linearly related to the weight of the grasped object. Less is known about the relationship between grip force and grip stiffness. We set out to determine variations to these dependencies in different tasks with and without visual feedback.

Constrained motion control on a hemispherical surface: path planning.

Surface-constrained motion, i.e., motion constraint by a rigid surface, is commonly found in daily activities.

Measuring parent perceptions of school climate.

Parents' attitudes about their children's schools matter. Their views can shape their children's attitudes about school, affect their levels of family-school engagement, and influence their residential and school enrollment decisions. In this article, we describe the development of a survey scale to assess parent perceptions of the climate of their child's school.

Vocal learning of a communicative signal in captive chimpanzees, Pan troglodytes.

We hypothesized that chimpanzees could learn to produce attention-getting (AG) sounds via positive reinforcement. We conducted a vocal assessment in 76 captive chimpanzees for their use of AG sounds to acquire the attention of an otherwise inattentive human. Fourteen individuals that did not produce AG sounds during the vocal assessment were evaluated for their ability to acquire the use of an AG sound through operant conditioning and to employ these sounds in an attention-getting context.

When kinesthesia becomes visual: a theoretical justification for executing motor tasks in visual space.

Several experimental studies in the literature have shown that even when performing purely kinesthetic tasks, such as reaching for a kinesthetically felt target with a hidden hand, the brain reconstructs a visual representation of the movement. In our previous studies, however, we did not observe any role of a visual representation of the movement in a purely kinesthetic task. This apparent contradiction could be related to a fundamental difference between the studied tasks.

Chimpanzees (Pan troglodytes) can wait, when they choose to: a study with the hybrid delay task.

Self-control has been studied in nonhuman animals using a variety of tasks. The inter-temporal choice (ITC) task presents choices between smaller-sooner (SS) and larger-later (LL) options. Using food amounts as rewards, this presents two problems: (a) choices of the LL option could either reflect self-control or instead result from animals' difficulty with pointing to smaller amounts of food; (b) there is no way to verify whether the subjects would not revert their choice for the LL option, if given the opportunity to do so during the ensuing delay.

What counts for 'counting'? Chimpanzees, , respond appropriately to relevant and irrelevant information in a quantity judgment task.

Nonhuman animals quantify all manner of things, and the way in which this is done is fairly well understood. However, little research has been conducted to determine how they know what is or is not relevant in the instances in which they quantify stimuli. We assessed how four chimpanzees chose between two sets of food items when the items were distributed across separate spatial arrays.

Weightlessness alters up/down asymmetries in the perception of self-motion.

In the present study, we investigated the effect of weightlessness on the ability to perceive and remember self-motion when passing through virtual 3D tunnels that curve in different direction (up, down, left, right). We asked cosmonaut subjects to perform the experiment before, during and after long-duration space flight aboard the International Space Station (ISS), and we manipulated vestibular versus haptic cues by having subjects perform the task either in a rigidly fixed posture with respect to the space station or during free-floating, in weightlessness. Subjects were driven passively at constant speed through the virtual 3D tunnels containing a single turn in the middle of a linear segment, either in pitch or in yaw, in increments of 12.