Daily Artificial Gravity Partially Mitigates Vestibular Processing Changes Associated with Head-down Tilt Bedrest.

Microgravity alters vestibular signaling and reduces body loading, driving sensory reweighting and adaptation. The unloading effects can be modelled using head down tilt bedrest (HDT). Artificial gravity (AG) has been hypothesized to serve as an integrated countermeasure for the physiological declines associated with HDT and spaceflight.

Impacts of spaceflight experience on human brain structure.

Spaceflight induces widespread changes in human brain morphology. It is unclear if these brain changes differ with varying mission duration or spaceflight experience history (i.e.

Daily artificial gravity is associated with greater neural efficiency during sensorimotor adaptation.

Altered vestibular signaling and body unloading in microgravity results in sensory reweighting and adaptation. Microgravity effects are well-replicated in head-down tilt bed rest (HDBR). Artificial gravity (AG) is a potential countermeasure to mitigate the effects of microgravity on human physiology and performance.

Changes in working memory brain activity and task-based connectivity after long-duration spaceflight.

We studied the longitudinal effects of approximately 6 months of spaceflight on brain activity and task-based connectivity during a spatial working memory (SWM) task. We further investigated whether any brain changes correlated with changes in SWM performance from pre- to post-flight. Brain activity was measured using functional magnetic resonance imaging while astronauts (n = 15) performed a SWM task.

Longitudinal MRI-visible perivascular space (PVS) changes with long-duration spaceflight.

Humans are exposed to extreme environmental stressors during spaceflight and return with alterations in brain structure and shifts in intracranial fluids. To date, no studies have evaluated the effects of spaceflight on perivascular spaces (PVSs) within the brain, which are believed to facilitate fluid drainage and brain homeostasis. Here, we examined how the number and morphology of magnetic resonance imaging (MRI)-visible PVSs are affected by spaceflight, including prior spaceflight experience.

Differential Relationships Between Brain Structure and Dual Task Walking in Young and Older Adults.

Almost 25% of all older adults experience difficulty walking. Mobility difficulties for older adults are more pronounced when they perform a simultaneous cognitive task while walking (i.e.

The Effects of 30 Minutes of Artificial Gravity on Cognitive and Sensorimotor Performance in a Spaceflight Analog Environment.

The altered vestibular signaling and somatosensory unloading of microgravity result in sensory reweighting and adaptation to conflicting sensory inputs. Aftereffects of these adaptive changes are evident postflight as impairments in behaviors such as balance and gait. Microgravity also induces fluid shifts toward the head and an upward shift of the brain within the skull; these changes are well-replicated in strict head-down tilt bed rest (HDBR), a spaceflight analog environment.

Case Report: No Evidence of Intracranial Fluid Shifts in an Astronaut Following an Aborted Launch.

Spaceflight induces lasting enlargement of the brain's ventricles as well as intracranial fluid shifts. These intracranial fluid shifts have been attributed to prolonged microgravity exposure, however, the potential effects of hypergravity exposure during launch and landing have yet to be elucidated. Here we describe a case report of a Crewmember who experienced an Aborted Launch ("CAL").

The Effects of Long Duration Spaceflight on Sensorimotor Control and Cognition.

Astronauts returning from spaceflight typically show transient declines in mobility and balance. Other sensorimotor behaviors and cognitive function have not been investigated as much. Here, we tested whether spaceflight affects performance on various sensorimotor and cognitive tasks during and after missions to the International Space Station (ISS).

Ophthalmic changes in a spaceflight analog are associated with brain functional reorganization.

Following long-duration spaceflight, some astronauts exhibit ophthalmic structural changes referred to as Spaceflight Associated Neuro-ocular Syndrome (SANS). Optic disc edema is a common sign of SANS. The origin and effects of SANS are not understood as signs of SANS have not manifested in previous spaceflight analog studies.

Null effects of levodopa on reward- and error-based motor adaptation, savings, and anterograde interference.

Dopamine signaling is thought to mediate reward-based learning. We tested for a role of dopamine in motor adaptation by administering the dopamine precursor levodopa to healthy participants in two experiments involving reaching movements. Levodopa has been shown to impair reward-based learning in cognitive tasks.

Altered cerebral perfusion in response to chronic mild hypercapnia and head-down tilt Bed rest as an analog for Spaceflight.

Purpose: Following prolonged stays on the International Space Station (ISS), some astronauts exhibit visual acuity changes, ophthalmological findings, and mildly elevated intracranial pressures as part of a novel process called spaceflight-associated neuro-ocular syndrome (SANS). To determine the pathophysiology of SANS, NASA conducted a multi-investigator study in which 11 healthy participants underwent head-down tilt bed rest, mimicking microgravity-induced cephalad fluid shifts, combined with elevated ambient CO levels similar to those on the ISS (HDT+CO). As part of that study, we examined the effects of HDT+CO on cerebral perfusion.

Reversal of Visual Feedback Modulates Somatosensory Plasticity.

Reversed visual feedback during unimanual training increases transfer of skills to the opposite untrained hand and modulates plasticity in motor areas of the brain. However, it is unclear if unimanual training with reversed visual feedback also affects somatosensory areas. Here we manipulated visual input during unimanual training using left-right optical reversing spectacles and tested whether unimanual training with reversed vision modulates somatosensory cortical excitability to facilitate motor performance.

Brain connectivity and behavioral changes in a spaceflight analog environment with elevated CO.

Astronauts are exposed to microgravity and elevated CO levels onboard the International Space Station. Little is known about how microgravity and elevated CO combine to affect the brain and sensorimotor performance during and after spaceflight. Here we examined changes in resting-state functional connectivity (FC) and sensorimotor behavior associated with a spaceflight analog environment.

The Impact of 6 and 12 Months in Space on Human Brain Structure and Intracranial Fluid Shifts.

As plans develop for Mars missions, it is important to understand how long-duration spaceflight impacts brain health. Here we report how 12-month ( = 2 astronauts) versus 6-month ( = 10 astronauts) missions impact brain structure and fluid shifts. We collected MRI scans once before flight and four times after flight.

The gradient of the reinforcement landscape influences sensorimotor learning.

Consideration of previous successes and failures is essential to mastering a motor skill. Much of what we know about how humans and animals learn from such reinforcement feedback comes from experiments that involve sampling from a small number of discrete actions. Yet, it is less understood how we learn through reinforcement feedback when sampling from a continuous set of possible actions.

Somatosensory perceptual training enhances motor learning by observing.

Action observation activates brain regions involved in sensory-motor control. Recent research has shown that action observation can also facilitate motor learning; observing a tutor undergoing motor learning results in functional plasticity within the motor system and gains in subsequent motor performance. However, the effects of observing motor learning extend beyond the motor domain.

Changes in corticospinal excitability associated with motor learning by observing.

While many of our motor skills are acquired through physical practice, we can also learn how to make movements by observing others. For example, individuals can learn how to reach in novel dynamical environments ('force fields', FF) by observing the movements of a tutor. Previous neurophysiological and neuroimaging studies in humans suggest a role for the motor system in motor learning by observing.

A multi-faceted approach of a nursing led education in response to MERS-CoV infection.

Background: The emergence of the Middle East respiratory syndrome-coronavirus (MERS-CoV) resulted in multiple healthcare associated outbreaks. In response, we developed a nurse-led program to screen and triage patients with MERS-CoV infection.

Methods: A formal educational program was implemented to ensure a standardized approach to care planning and delivery.

Dissociating error-based and reinforcement-based loss functions during sensorimotor learning.

It has been proposed that the sensorimotor system uses a loss (cost) function to evaluate potential movements in the presence of random noise. Here we test this idea in the context of both error-based and reinforcement-based learning. In a reaching task, we laterally shifted a cursor relative to true hand position using a skewed probability distribution.

Functional connectivity between somatosensory and motor brain areas predicts individual differences in motor learning by observing.

Action observation can facilitate the acquisition of novel motor skills; however, there is considerable individual variability in the extent to which observation promotes motor learning. Here we tested the hypothesis that individual differences in brain function or structure can predict subsequent observation-related gains in motor learning. Subjects underwent an anatomical MRI scan and resting-state fMRI scans to assess preobservation gray matter volume and preobservation resting-state functional connectivity (FC), respectively.

Does the sensorimotor system minimize prediction error or select the most likely prediction during object lifting?

Unlabelled: The human sensorimotor system is routinely capable of making accurate predictions about an object's weight, which allows for energetically efficient lifts and prevents objects from being dropped. Often, however, poor predictions arise when the weight of an object can vary and sensory cues about object weight are sparse (e.g.

Functional Plasticity in Somatosensory Cortex Supports Motor Learning by Observing.

An influential idea in neuroscience is that the sensory-motor system is activated when observing the actions of others [1, 2]. This idea has recently been extended to motor learning, in which observation results in sensory-motor plasticity and behavioral changes in both motor and somatosensory domains [3-9]. However, it is unclear how the brain maps visual information onto motor circuits for learning.