Paul A. DiZio - US grants

The goal of the proposed work is to enhance the feasibility of using virtual environments (VE) for the teaching of science, technology, engineering and mathematics (STEM) at all grade levels in order to maximize the effectiveness of curricula. In principle, the applications of VEs for training in physics, chemistry, astronomy, engineering, biology and mathematics are unlimited. However, in practice, their usefulness has been limited by undesirable side effects of motion sickness, dizziness, and postural instability. Consequently, users spontaneously limit their head and body movements in frequency and amplitude and move more tentatively. Many have to terminate participation. In order for VEs to be a viable tool for educators it is necessary first to identify the primary factors that contribute to motion sickness, postural instability and impaired eye-head coordination in VEs. A coordinated series of experiments is proposed using as a model an educational VE designed to teach molecular and chemical structure. The relationship of field-of-view, tracking delays in scene updating, and visual resolution to these side effects will be determined. Techniques involving various types of haptic cuing of body and environment orientation will be used to suppress side effects and increase the user?s mobility and ability to learn the VE. Head movement contingent blanking of the visual field will be tested as a way of attenuating motion sickness, postural instability, and preventing derangements of gaze control. The goal of the proposed research is to enable students to move naturally and freely while exploring the VE without restricting their activities and without their becoming nauseous, dizzy, or unstable. Achieving this would be transformative by increasing the usefulness of immersive VEs for training in STEM disciplines.

Complexity science involves the study of situations where the behavior of a system is not easily understood by studying its parts in isolation, but depends crucially on understanding how the parts interact (the weather, turbulence, and the economy are among the most familiar examples of complex systems). Complex systems analysis has been increasingly successfully applied by psychologists and neuroscientists to the study of perception, action, and cognition. The NSF-funded research project by psychologists James Lackner and Paul DiZio at Brandeis University is an example of the application of complexity science to human movement and motor control.

Lackner and DiZio take the approach of beginning with a deceptively simple question, study it in a deceptively simple experimental paradigm, and analyze the task and behavior with a deceptively simple model. The question is how far must a person be moved off-balance before they will take a step to avoid a fall. With the Hold & Release (H&R) technique, the experimenter applies a small force to the sternum of the research participants, which they resist in order to maintain balance. When the force is released participants must make postural adjustments to maintain balance and if the force is large enough a step is required. It appears that a (relatively) simple linear model -- the one-leg inverted pendulum model -- can account for participants' postural adjustments in this situation. The model breaks down, however, when the force is large enough to require the participant to take a step in order to maintain balance. This requires the transition to a more complex non-linear model which assumes the two legs operate in a coordinated but asymmetrical fashion. Lackner and DiZio will test this model by performing the H&R task in a rotating room. This simple next step adds additional forces (especially rotational Coriolis forces that serve to pull the movement away from the intended trajectory but that change continuously as a function of the limb's velocity) and additional degrees of freedom for participants' responses that provide a rigorous environment for testing the new model. The model is refined enough to make detailed predictions about participants' stance, about which combinations of forces will push them to the stepping threshold, and even with which foot the step will be made.

If successful, Lackner and DiZio will have succeeded in taking a major step towards unifying the study of posture and locomotion, which until now have been studied as essentially separate processes. It is clear that any improvement in our understanding of motor control can have implications for the assessment and treatment of movement disorders, but this approach is particularly promising because H&R measurements are easy to make and the detailed model is so tightly coupled to the measurement paradigm. The interdisciplinary nature of complex systems research is also demonstrated by this project, in which psychologists Lackner and DiZio will employ a Ph.D. physicist as a post-doctoral researcher. Undergraduate physics majors regularly assist with Lackner and DiZio's research.

DESCRIPTION (provided by applicant): Adults who adapt to a perturbing force on their arm produced by a robotic manipulandum later show aftereffects when reaching with the robot deactivated but move accurately if they let go of the robot. This shows that what they learn about how to make goal-directed reaching movements when grasping a robotic manipulandum generating a movement-contingent force does not carry over to reaching without the robot. This is one example of a growing body of evidence indicating that we learn distinct predictive strategies for moving our own arm and for moving external objects, and we use these strategies in an appropriate self/object context. We have recently shown that this context-specific self/object distinction within the motor system is a developmental achievement that appears at about seven years of age in typically developing children. Our studies also show that there is not an absolute maturational time table for the emergence of context-specific self/object motor adaptation because it can be accelerated if appropriate experience is provided. In addition, we have exciting preliminary results from a study of children with high functioning autism (HFA) in which we are finding that they are as capable as typically developing children of learning to compensate for a perturbing robotic manipulandum (object) but are delayed in learning not to carry this over to the free reaching (self) context. Our overall aims are to confirm this preliminary finding in children with HFA and to test a hypothesis about how to accelerate self/object context-specific dynamic motor learning in typically developing children as well as in children with HFA. The outcomes of this project will provide a better understanding of the development of context-specific dynamic motor adaptation in typically developing children, a clearer understanding of motor deficits in autism, and a therapeutic method for enhancing motor learning in children with HFA - especially learning to interact with dynamic objects. A positive outcome will also open future avenues for investigating typical and disordered development of motor interactions between individuals. PUBLIC HEALTH RELEVANCE: We will investigate children's capacity separately adjust their neuromotor control to account for their own rapidly changing bodies and for forces imposed by novel external objects. Our studies will include typically developing children, children with autism. The outcomes will be a better understanding of motor development in typically developing children, a clearer understanding of motor deficits in autism and a potential therapy for improving the development of dynamic motor interactions. Strong preliminary results indicate positive outcomes which will open a future avenue for investigating typical and disordered development of motor interactions between individuals.

An essential issue in the movement sciences is to understand how people maintain upright posture and balance. In everyday life, people often simultaneously turn and reach to pick up objects or to place objects. Such movements are typically accurate and seem virtually effortless. However, when an arm movement is made during ongoing trunk rotation large inertial forces are generated on the reaching arm. These forces are so large that huge errors in reaching and destabilization of posture would occur if the central nervous system (CNS) did not take them into account. In this program of research, two series of experiments will examine the interaction of the control of self-rotation and of arm-torso dynamics. Series 1 will evaluate the kinematics of reaching and turning, postural sway, arm joint torques, and ground reaction forces at the feet. Series 2 will assess these variables in tasks involving active and passive torso rotation and reaching. The results will indicate whether the CNS control of trunk rotation and arm reaching are a) parallel and independent, b) hierarchical with information about intended trunk rotation contributing to separate control of torso and arm movements, or c) distributed with a single internal model for reaching and turning.

Falling in the elderly is a major health problem. Neurological diseases that affect torso and or limb movement control (e.g., Parkinson's disease) also increase the likelihood of falls. This research should provide a scientific basis for developing rehabilitation strategies that compensate for trunk-generated forces on the limbs and minimize the likelihood of falling.

Motion sickness has always accompanied the introduction of new transportation and display technologies. Although the active drivers of vehicles are usually less susceptible to motion sickness than the passive passengers, the development of self-driving cars (autonomous vehicles) makes all of the occupants passengers. One benefit of autonomous vehicles is that they free passengers to perform many activities typically done at their homes or offices. Unfortunately, when these activities require focused visual attention, such as reading, working, or watching videos, the likelihood of experiencing motion sickness increases. The goals of the current project are to identify the key factors that contribute to motion sickness in autonomous vehicles, to identify factors that characterize who will be most susceptible, and to develop ways to reduce motion sickness and declines in performance.

The project will evaluate three aspects of individuals' responses to stimulation that might provoke motion sickness: 1) the initial sensitivity to a stimulus, 2) the decay of motion sickness severity following discontinuation of stimulation, and 3) the rate of adaptation following repeated stimulation. Of key concern is whether for a given individual, initial sensitivity, decay, and adaptation will be consistent across different types of sickness-inducing stimulation. The approach is based on a mechanistic model of motion sickness derived from neurophysiological and behavioral evidence concerning the relationship between motion sickness onset and disruptions of vestibulo-ocular and vestibulo-motor control. The role of active control of forthcoming stimulation (the fact that the driver rarely becomes motion sick) will be systematically evaluated to determine the extent to which anticipation plays a role in sickness prevention. The investigators will compare initial sensitivity, decay, and adaptability of motion sickness across stimulation involving a) the semicircular canals of the inner ear, which are sensitive to angular acceleration, b) the otolith organs of the inner ear, which are sensitive to linear acceleration, c) both in combination, and d) vision in order to assess their contributions to an individual's overall pattern of motion sickness vulnerability under active and passive conditions. The aim is to develop predictors of an individual's sensitivity to the factors contributing to motion sickness in autonomous vehicles (control vs. no-control, frequency and amplitude dependent characteristics of vehicle motion, and focal visual attention tasks). This capability would allow remedial steps to be taken to reduce sickness likelihood and optimize the benefits of this new technology.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Project Summary The goal of this training program entitled ?Predoctoral Training at the Interface of Brain, Body, and Behavior? (BBB) at Brandeis University is to produce a new generation of scientists equipped to discover the mechanisms of a broad range of healthy and clinically disordered mental and behavioral functions by applying both the core concepts and methods of psychology and the interface of these methods with neuroscience and biomedical research. This new application under NIGMS PAR-17- 341 builds on a T32 program that is expiring after ten years of NIGMS support. Neuroscience at Brandeis is an umbrella for extensive overlap of Psychology and Biology faculty, but co-training of PhD students has thus far been prohibited by differences between the Psychology and Neuroscience graduate programs. The old BBB program supported Psychology PhD students and provided them with supplementary training in neuroscience and biomedicine, and the new BBB proposes to support both Psychology and Neuroscience PhD students and to give them complementary co-training in each other?s disciplines. Psychology appointees will be supported in years 1 and 2 and Neuroscience students in years 2 and 3, but all will engage in BBB activities from year 1 to graduation. The old BBB training grant had 3 NIGMS slots, and the new BBB proposes 4 NIGMS slots evenly divided between the Psychology and Neuroscience, supplemented by one additional slot pledged by Brandeis University. Psychology and Neuroscience have mutually revised their PhD programs such that BBB students can satisfy departmental course electives with BBB-specific classes from the other program. Additional required BBB co-training students includes research mentoring in the same laboratories, research rotations, a common module for training in rigor and reproducibility, coordinated journal clubs, and joint colloquia. These BBB requirements, departmental requirements, and enhancement activities are designed to provide students broad and deep training on specific bio-behavioral problems and quantitative training in research implementation and rigor as well as mentoring in how to develop, communicate, and fund an independent scientific program. The training faculty include 12 members with primary appointments in Psychology and 7 in Biology, all of whom are members of the Volen National Center for Complex Systems which houses the Neuroscience PhD program. One of the Psychology BBB faculty is a non-tenure track specialist who teaches and advises students on statistics and research design, with a special emphasis on methods of rigor and reproducibility. Another major aim of our program is to grow by attracting and fostering a diverse group of students. Over the past 10 years, 21% of students in the Psychology BBB program have been under-represented minorities, and the Neuroscience program has enrolled 13-20% URMs per year, and we aim to continue this trend.