Dual tasks involve performance in multiple systems simultaneously and provide the opportunity to evaluate adaptations, re-adaptations, and multiday performance savings in rodents and humans. Savings refers to faster relearning, or gains in performance that come from repetition on a task. Both savings and adaptations are imperative to mission success with exposure to SFS and varying task demands. Therefore, the main objectives of this proposal are two-fold: 1) to evaluate the impact of SFS, alone and combined, on neural activity during dual tasks, periods of inactivity, and sleep, and 2) to assess the feasibility of using neural activity to predict subsequent adaptations and multiday performance savings.

To accomplish these research objectives, neural recording techniques will be used to establish system-wide SFS effects on independent and cooperative (team cohesion) dual task performance and to characterize the neural mechanisms underlying adaptations and savings, as well as the feasibility of predicting future performance. Our state-of-the-art established wireless neural recording techniques will be conducted while rats perform versions of the behavioral assessments that vary in complexity and during offline periods of inactivity (i.e., neural replay) to examine cognitive, sensorimotor, and vestibular function. Sleep disruptions are commonly reported among astronauts, which have deleterious effects on performance, including reaction time. Therefore, we will also investigate the initial effects of SR exposure on neural activity during sleep, as well as the effect of SD on sleep characteristics (spindles, stage duration). In addition, we will assess the feasibility of predicting neural network function, adaptation, and savings, from sleep characteristics (including sleep stage durations and sleep spindles that are critical to memory).

Despite the fact that both independent and cooperative (team cohesion) performance depends on varying demands (single versus dual) in many of the tasks that astronauts must perform in space, the impact that SR and SD have on such performance is unknown. Thus, our proposed studies will determine the relative sensitivity of independent and cooperative (team cohesion) performance on single and dual tasks to these SFS, compared to mono-dimensional tasks that have been the mainstay of rodent-based research to-date. This work also has the potential to identify underlying neurobiological mechanisms of adaptations in a rodent SFS model and to provide a basis to identify resilient and susceptible factors. This work may lead to an understanding of how to promote adaptations and performance savings across time in individuals that are especially susceptible to the effects of SFS.

Given the widespread effects of SFS, understanding how adaptations, readaptations, and savings occur within multiple systems (sensorimotor, cognitive, social cooperative) in rats identified to be resilient or susceptible will be imperative to develop effective therapeutic strategies. This will be the first study to evaluate both independent and cooperative, team cohesion, performance in tasks of sensorimotor and cognitive function in a rodent model. Performing both autonomously and cooperatively with a team is critical for long duration missions in deep space along with determining how to maximize team dynamics.

In addition, the proposed work will fill a large gap in the acute effects of SFS immediately after space radiation exposure by examining behavior and neural activity acutely after post-irradiation exposure out to protracted timepoints. The implications of this work will extend beyond the space biology animal studies program to sleep disruptions that commonly occur on Earth, neural network dysfunction, and adaptation, readaptations, and savings in patients on Earth. Specifically, many of the same impairments observed after space radiation exposure and sleep disruptions are also observed in rodent models of stroke; it is likely that a similar mechanistic basis exists for these deficits as well as the compensation in performance that occurs over time. Further, since this will be the first study to evaluate dual motor-cognitive tasks during independent and cooperative team work in a rodent model, it will provide validation for the use of these assessments in other rodent models outside of SFS. Therefore, this work will have applications for rodent models of stroke and clinical populations. Lastly, evaluating neural network function in rodent models of ground based SFS will provide a basis of comparison for functional magnetic resonance imaging studies with astronauts.

The progress of this work was delayed for several reasons. The Principal Investigator accepted a new appointment at the University of Nevada, Las Vegas as an Assistant Professor which required the transfer of this grant from Eastern Virginia Medical School to the University of Nevada, Las Vegas. Thus, the creation and release of grant funds in the fall 2023 account for this grant was delayed; this delayed the overall work on radiation experiments at Brookhaven National Laboratory to spring 2024 due to limited exposure timeframes.

Dual tasks involve performance in multiple systems simultaneously and provide the opportunity to evaluate adaptations, re-adaptations, and multiday performance savings in rodents and humans. Savings refers to faster relearning, or gains in performance that come from repetition on a task. Both savings and adaptations are imperative to mission success with exposure to SFS and varying task demands. Therefore, the main objectives of this proposal are two-fold: 1) to evaluate the impact of SFS, alone and combined, on neural activity during dual tasks, periods of inactivity, and sleep, and 2) to assess the feasibility of using neural activity to predict subsequent adaptations and multiday performance savings.

To accomplish these research objectives, neural recording techniques will be used to establish system-wide SFS effects on independent and cooperative (team cohesion) dual task performance and to characterize the neural mechanisms underlying adaptations and savings, as well as the feasibility of predicting future performance. Our state-of-the-art established wireless neural recording techniques will be conducted while rats perform versions of the behavioral assessments that vary in complexity and during offline periods of inactivity (i.e., neural replay) to examine cognitive, sensorimotor, and vestibular function. Sleep disruptions are commonly reported among astronauts, which have deleterious effects on performance, including reaction time. Therefore, we will also investigate the initial effects of SR exposure on neural activity during sleep, as well as the effect of SD on sleep characteristics (spindles, stage duration). In addition, we will assess the feasibility of predicting neural network function, adaptation, and savings, from sleep characteristics (including sleep stage durations and sleep spindles that are critical to memory).

Despite the fact that both independent and cooperative (team cohesion) performance depends on varying demands (single versus dual) in many of the tasks that astronauts must perform in space, the impact that SR and SD have on such performance is unknown. Thus, our proposed studies will determine the relative sensitivity of independent and cooperative (team cohesion) performance on single and dual tasks to these SFS, compared to mono-dimensional tasks that have been the mainstay of rodent-based research to-date. This work also has the potential to identify underlying neurobiological mechanisms of adaptations in a rodent SFS model and to provide a basis to identify resilient and susceptible factors. This work may lead to an understanding of how to promote adaptations and performance savings across time in individuals that are especially susceptible to the effects of SFS.