Assessing the validity of an online assessment of motor learning

To understand motor learning we must observe improvements in the performance of a motor behavior over time. Current laboratory approaches to measuring motor learning are not accessible to all populations, and this lack of accessibility limits the ability of researchers to gain information about developmental processes and medical conditions that impact motor control. To date, there are a handful of portable motor learning tools that use devices such as smartphones and tablets but very few fully remote options. We have created a web-based application to assess visuomotor adaptation, a gold standard approach to studying motor learning, in a remote setting. The overarching goal of this study was to provide evidence that a web-based application is a valid way to assess motor learning in healthy younger and older adults. Younger adults (n=24) and older adults (n=19) participated in this study. Each participant met with a researcher via Zoom and shared their screen while performing the visuomotor rotation (VMR) task and a cognitive battery. Data from the application was then compared to data previously collected using traditional laboratory equipment. Results show that the online application produced similar learning curves compared to the laboratory task. Expected age differences were not seen using the application, however. Surprisingly, older adults performed better using the application than in the laboratory while younger adults performed the same across platforms. Also, our cognitive measures were not found to be associated with learning in the application version of the VMR task. Our data show that this application can be used in research with results that are similar to those acquired in a laboratory setting with the benefit of the application improving accessibility to broader populations

Sequential Neural Processes in Abacus Mental Addition: An EEG and fMRI Case Study

Abacus experts are able to mentally calculate multi-digit numbers rapidly. Some behavioral and neuroimaging studies have suggested a visuospatial and visuomotor strategy during abacus mental calculation. However, no study up to now has attempted to dissociate temporally the visuospatial neural process from the visuomotor neural process during abacus mental calculation. In the present study, an abacus expert performed the mental addition tasks (8-digit and 4-digit addends presented in visual or auditory modes) swiftly and accurately. The 100% correct rates in this expert’s task performance were significantly higher than those of ordinary subjects performing 1-digit and 2-digit addition tasks. ERPs, EEG source localizations, and fMRI results taken together suggested visuospatial and visuomotor processes were sequentially arranged during the abacus mental addition with visual addends and could be dissociated from each other temporally. The visuospatial transformation of the numbers, in which the superior parietal lobule was most likely involved, might occur first (around 380 ms) after the onset of the stimuli. The visuomotor processing, in which the superior/middle frontal gyri were most likely involved, might occur later (around 440 ms). Meanwhile, fMRI results suggested that neural networks involved in the abacus mental addition with auditory stimuli were similar to those in the visual abacus mental addition. The most prominently activated brain areas in both conditions included the bilateral superior parietal lobules (BA 7) and bilateral middle frontal gyri (BA 6). These results suggest a supra-modal brain network in abacus mental addition, which may develop from normal mental calculation networks

Neural correlates of multi-day learning and savings in sensorimotor adaptation

Abstract In the present study we evaluated changes in neural activation that occur over the time course of multiple days of sensorimotor adaptation, and identified individual neural predictors of adaptation and savings magnitude. We collected functional MRI data while participants performed a manual adaptation task during four separate test sessions over a three-month period. This allowed us to examine changes in activation and associations with adaptation and savings at subsequent sessions. Participants exhibited reliable savings of adaptation across the four sessions. Brain activity associated with early adaptation increased across the sessions in a variety of frontal, parietal, cingulate, and temporal cortical areas, as well as various subcortical areas. We found that savings was positively associated with activation in several striatal, parietal, and cingulate cortical areas including the putamen, precuneus, angular gyrus, dorsal anterior cingulate cortex (dACC), and cingulate motor area. These findings suggest that participants may learn how to better engage cognitive processes across days, potentially reflecting improvements in action selection. We propose that such improvements may rely on action-value assignments, which previously have been linked to the dACC and striatum. As correct movements are assigned a higher value than incorrect movements, the former are more likely to be performed again

Developmental and age differences in visuomotor adaptation across the lifespan

Health and self-regulatio

Individual differences in explicit and implicit visuomotor learning and working memory capacity

The theoretical basis for the association between high working memory capacity (WMC) and enhanced visuomotor adaptation is unknown. Visuomotor adaptation involves interplay between explicit and implicit systems. We examined whether the positive association between adaptation and WMC is specific to the explicit component of adaptation. Experiment 1 replicated the positive correlation between WMC and adaptation, but revealed this was specific to the explicit component of adaptation, and apparently driven by a sub-group of participants who did not show any explicit adaptation in the correct direction. A negative correlation was observed between WMC and implicit learning. Experiments 2 and 3 showed that when the task restricted the development of an explicit strategy, high WMC was no longer associated with enhanced adaptation. This work reveals that the benefit of high WMC is specifically linked to an individual’s capacity to use an explicit strategy. It also reveals an important contribution of individual differences in determining how adaptation is performed

How Aging Affects Visuomotor Adaptation and Retention in a Precision Walking Paradigm

Motor learning is a lifelong process. However, age-related changes to musculoskeletal and sensory systems alter the relationship (or mapping) between sensory input and motor output, and thus potentially affect motor learning. Here we asked whether age affects the ability to adapt to and retain a novel visuomotor mapping learned during overground walking. We divided participants into one of three groups (n = 12 each) based on chronological age: a younger-aged group (20–39 years old); a middle-aged group (40–59 years old); and an older-aged group (60–80 years old). Participants learned a new visuomotor mapping, induced by prism lenses, during a precision walking task. We assessed retention one-week later. We did not detect significant effects of age on measures of adaptation or savings (defined as faster relearning). However, we found that older adults demonstrated reduced initial recall of the mapping, reflected by greater foot-placement error during the first adaptation trial one-week later. Additionally, we found that increased age significantly associated with reduced initial recall. Overall, our results suggest that aging does not impair adaptation and that older adults can demonstrate visuomotor savings. However, older adults require some initial context during relearning to recall the appropriate mapping

USING A REVERSE VISUALLY GUIDED REACHING TASK TO DISTINGUISH BETWEEN HEALTHY AGING AND EARLY ALZHEIMER’S DISEASE

Changes in motor behavior may function as a proxy for cognitive decline. While Alzheimer\u27s disease (AD) is associated with impairments in learning and memory, recent studies suggest that subtle changes in motor task performance may reflect early cognitive changes. For example, the visuomotor rotation task that manipulates visual feedback about hand position during reaching movements, can be used to examine cognitive changes in aging populations. The current study used the reverse visually guided reaching task (rVGR) which rotates visual feedback of participant’s hand position 180⁰ relative to the actual hand position. We sought to expand on previous literature by recruiting cognitively impaired individuals to characterize changes in rVGR performance in early AD. We also examined learning curves to assess the impact of cognitive impairment on learning in the rVGR task and probed the cognitive correlates of rVGR performance with a neuropsychological battery. We recruited young adults, and older adults (55 – 85 years old) with and without cognitive impairment to complete a VGR task with veridical mapping, and then the rVGR task. Overall, cognitively impaired adults exhibited longer reaction times and performed more corrective movements. Age differences were observed for nearly all overall measures of performance. The largest differences between healthy older adults and cognitively impaired adults were identified in the earliest stages of the learning curve. In the first few movements, the cognitively impaired group made more angular errors. Both overall- and early- measures of performance were correlated with measures of cognitive control. These findings add to the growing literature suggesting that sensorimotor adaptation tasks may be sensitive to early cognitive changes in AD

Study protocol to examine the effects of spaceflight and a spaceflight analog on neurocognitive performance: extent, longevity, and neural bases

Abstract Background Long duration spaceflight (i.e., 22 days or longer) has been associated with changes in sensorimotor systems, resulting in difficulties that astronauts experience with posture control, locomotion, and manual control. The microgravity environment is an important causal factor for spaceflight induced sensorimotor changes. Whether spaceflight also affects other central nervous system functions such as cognition is yet largely unknown, but of importance in consideration of the health and performance of crewmembers both in- and post-flight. We are therefore conducting a controlled prospective longitudinal study to investigate the effects of spaceflight on the extent, longevity and neural bases of sensorimotor and cognitive performance changes. Here we present the protocol of our study. Methods/design This study includes three groups (astronauts, bed rest subjects, ground-based control subjects) for which each the design is single group with repeated measures. The effects of spaceflight on the brain will be investigated in astronauts who will be assessed at two time points pre-, at three time points during-, and at four time points following a spaceflight mission of six months. To parse out the effect of microgravity from the overall effects of spaceflight, we investigate the effects of seventy days head-down tilted bed rest. Bed rest subjects will be assessed at two time points before-, two time points during-, and three time points post-bed rest. A third group of ground based controls will be measured at four time points to assess reliability of our measures over time. For all participants and at all time points, except in flight, measures of neurocognitive performance, fine motor control, gait, balance, structural MRI (T1, DTI), task fMRI, and functional connectivity MRI will be obtained. In flight, astronauts will complete some of the tasks that they complete pre- and post flight, including tasks measuring spatial working memory, sensorimotor adaptation, and fine motor performance. Potential changes over time and associations between cognition, motor-behavior, and brain structure and function will be analyzed. Discussion This study explores how spaceflight induced brain changes impact functional performance. This understanding could aid in the design of targeted countermeasures to mitigate the negative effects of long-duration spaceflight.http://deepblue.lib.umich.edu/bitstream/2027.42/112560/1/12883_2013_Article_922.pd

Inducing Visuomotor Adaptation Using Virtual Reality Gaming with a Virtual Shift as a Treatment for Unilateral Spatial Neglect

Unilateral spatial neglect after stroke is characterized by reduced responses to stimuli on the contralesional side, causing significant impairments in self-care and safety. Conventional visuomotor adaptation (VMA) with prisms that cause a lateral shift of the visual scene can decrease neglect symptoms but is not engaging according to patients. Performing VMA within a virtual reality (VR) environment may be more engaging but has never been tested. To determine if VMA can be elicited in a VR environment, healthy subjects (n=7) underwent VMA that was elicited by either wearing prisms that caused an optical shift, or by application of a virtual shift of the hand cursor within the VR environment. A low cost VR system was developed by coupling the Kinect v2 gaming sensor to online games via the Flexible Action and Articulated Skeleton Toolkit (FAAST) software. The adaptation phase of training consisted of a reaching task in online games or in a custom target pointing program. Following the adaptation phase the optical or virtual shift was removed and participants were assessed during the initial portion of the de-adaptation phase for the presence of an after-effect on their reaching movements, with lateral reaching errors indicating the successful induction of VMA. Results show that practicing reaching in a VR environment with a virtual shift lead to a horizontal after-effect similar to conventional prism adaptation. The results demonstrate that VMA can be elicited in a VR environment and suggest that VR gaming therapy could be used to improve recovery from unilateral spatial neglect

Reversing motor adaptation deficits in the ageing brain using non-invasive stimulation

Healthy ageing is characterised by deterioration of motor performance. In normal circumstances motor adaptation corrects for movements’ inaccuracies and as such, it is critical in maintaining optimal motor control. However, motor adaptation performance is also known to decline with age. Anodal transcranial direct current stimulation (TDCS) of the cerebellum and the primary motor cortex (M1) have been found to improve visuomotor adaptation in healthy young and older adults. However, no study has directly compared the effect of TDCS on motor adaptation between the two age populations. The aim of our study was to investigate whether the application of anodal TDCS over the lateral cerebellum and M1 affected motor adaptation in young and older adults similarly. Young and older participants performed a visuomotor rotation task and concurrently received TDCS over the left M1, the right cerebellum or received sham stimulation. Our results replicated the finding that older adults are impaired compared to the young adults in visuomotor adaptation. At the end of the adaptation session, older adults displayed a larger error (−17 deg) than the young adults (−10 deg). The stimulation of the lateral cerebellum did not change the adaptation in both age groups. In contrast, anodal TDCS over M1 improved initial adaptation in both age groups by around 30% compared to sham and this improvement lasted up to 40 min after the end of the stimulation. These results demonstrate that TDCS of M1 can enhance visuomotor adaptation, via mechanisms that remain available in the ageing population