Alterations in brain white matter contributing to age-related slowing of task switching performance: The role of radial diffusivity and magnetization transfer ratio.

Successfully switching between tasks is critical in many daily activities. Age-related slowing of this switching behavior has been documented extensively, but the underlying neural mechanisms remain unclear. Here, we investigated the contribution of brain white matter changes associated with myelin alterations to age-related slowing of switching performance.

Microstructural organization of corpus callosum projections to prefrontal cortex predicts bimanual motor learning.

The corpus callosum (CC) is the largest white matter tract in the brain. It enables interhemispheric communication, particularly with respect to bimanual coordination. Here, we use diffusion tensor imaging (DTI) in healthy humans to determine the extent to which structural organization of subregions within the CC would predict how well subjects learn a novel bimanual task.

Low-dose prednisone inclusion in a methotrexate-based, tight control strategy for early rheumatoid arthritis: a randomized trial.

Background: Treatment strategies for tight control of early rheumatoid arthritis (RA) are highly effective but can be improved.

Objective: To investigate whether adding prednisone, 10 mg/d, at the start of a methotrexate (MTX)-based treatment strategy for tight control in early RA increases its effectiveness.

Design: A 2-year, prospective, randomized, placebo-controlled, double-blind, multicenter trial (CAMERA-II [Computer Assisted Management in Early Rheumatoid Arthritis trial-II]).

Disturbed cortico-subcortical interactions during motor task switching in traumatic brain injury.

The ability to suppress and flexibly adapt motor behavior is a fundamental mechanism of cognitive control, which is impaired in traumatic brain injury (TBI). Here, we used a combination of functional magnetic resonance imaging and diffusion weighted imaging tractography to study changes in brain function and structure associated with motor switching performance in TBI. Twenty-three young adults with moderate-severe TBI and twenty-six healthy controls made spatially and temporally coupled bimanual circular movements.

Brain activity during ankle proprioceptive stimulation predicts balance performance in young and older adults.

Proprioceptive information from the foot/ankle provides important information regarding body sway for balance control, especially in situations where visual information is degraded or absent. Given known increases in catastrophic injury due to falls with older age, understanding the neural basis of proprioceptive processing for balance control is particularly important for older adults. In the present study, we linked neural activity in response to stimulation of key foot proprioceptors (i.

Diffusion tensor imaging metrics of the corpus callosum in relation to bimanual coordination: effect of task complexity and sensory feedback.

When manipulating objects with both hands, the corpus callosum (CC) is of paramount importance for interhemispheric information exchange. Hence, CC damage results in impaired bimanual performance. Here, healthy young adults performed a complex bimanual dial rotation task with or without augmented visual feedback and according to five interhand frequency ratios (1:1, 1:3, 2:3, 3:1, 3:2).

Testing multiple coordination constraints with a novel bimanual visuomotor task.

The acquisition of a new bimanual skill depends on several motor coordination constraints. To date, coordination constraints have often been tested relatively independently of one another, particularly with respect to isofrequency and multifrequency rhythms. Here, we used a new paradigm to test the interaction of multiple coordination constraints.

Bimanual coordination and corpus callosum microstructure in young adults with traumatic brain injury: a diffusion tensor imaging study.

Bimanual actions are ubiquitous in daily life. Many coordinated movements of the upper extremities rely on precise timing, which requires efficient interhemispheric communication via the corpus callosum (CC). As the CC in particular is known to be vulnerable to traumatic brain injury (TBI), furthering our understanding of its structure-function association is highly valuable for TBI diagnostics and prognosis.

The neural basis of central proprioceptive processing in older versus younger adults: an important sensory role for right putamen.

Our sense of body position and movement independent of vision (i.e., proprioception) relies on muscle spindle feedback and is vital for performing motor acts.

Correlations between white matter integrity and motor function in traumatic brain injury patients.

Background: Deterioration of motor function is one of several clinical manifestations following traumatic brain injury (TBI) in children and adolescents.

Objective: To investigate the relationship between white matter (WM) integrity using diffusion tensor imaging (DTI) and motor functioning in young TBI patients.

Methods: A group with moderate to severe TBI (n = 24) and a control group (n = 17) were scanned using DTI along with standard anatomical scans.

Brain-behavior relationships in young traumatic brain injury patients: DTI metrics are highly correlated with postural control.

Traumatic brain injury (TBI) is a major cause of impairment and functional disability in children and adolescents, including deterioration in fine as well as gross motor skills. The aim of this study was to assess deficits in sensory organization and postural ability in a young group of TBI patients versus controls by using quantitative force-platform recordings, and to test whether balance deficits are related to variation in structural properties of the motor and sensory white matter pathways. Twelve patients with TBI and 14 controls (aged 8-20 years) performed the Sensory Organisation Test (SOT) protocol of the EquiTest (Neurocom).