Proprioceptive recalibration following implicit visuomotor adaptation is preserved in Parkinson's disease.

Individuals with Parkinson's disease (PD) and healthy adults demonstrate similar levels of visuomotor adaptation provided that the distortion is small or introduced gradually, and hence, implicit processes are engaged. Recently, implicit processes underlying visuomotor adaptation in healthy individuals have been proposed to include proprioceptive recalibration (i.e.

Computerised Dynamic Posturography in Premanifest and Manifest individuals with Huntington's Disease.

Evidence from small-scale studies indicates that impairments in postural stability are an early and disabling feature of Huntington's disease (HD) and may be a useful clinical endpoint for disease modifying trials. Larger studies are needed to confirm these preliminary findings and the suitability of postural stability outcomes as clinical endpoints. Static and dynamic postural stability were evaluated in 54 premanifest HD, 36 manifest HD and 45 healthy individuals using the Sensory Organization Test (SOT) and Limits of Stability (LOS) test.

Retention of proprioceptive recalibration following visuomotor adaptation.

We have recently shown that visuomotor adaptation following reaches with a misaligned cursor not only induces changes in an individual's motor output, but their proprioceptive sense of hand position as well. Long-term changes are seen in motor adaptation; however, very little is known about the retention of changes in felt hand position. We sought to evaluate whether this recalibration in proprioception, following visuomotor adaptation, is sufficiently robust to be retained the following day (~24 h later), and if so, to determine its extent.

Reach adaptation and proprioceptive recalibration following terminal visual feedback of the hand.

We have shown that when subjects reach with continuous, misaligned visual feedback of their hand, their reaches are adapted and proprioceptive sense of hand position is recalibrated to partially match the visual feedback (Salomonczyk et al., 2011). It is unclear if similar changes arise after reaching with visual feedback that is provided only at the end of the reach (i.

Intermanual transfer and proprioceptive recalibration following training with translated visual feedback of the hand.

Reaching with visual feedback that is misaligned with respect to the actual hand's location leads to changes in reach trajectories (i.e., visuomotor adaptation).

The role of the cross-sensory error signal in visuomotor adaptation.

Reaching to targets with misaligned visual feedback of the hand leads to changes in proprioceptive estimates of hand position and reach aftereffects. In such tasks, subjects are able to make use of two error signals: the discrepancy between the desired and actual movement, known as the sensorimotor error signal, and the discrepancy between visual and proprioceptive estimates of hand position, which we refer to as the cross-sensory error signal. We have recently shown that mere exposure to a sensory discrepancy in the absence of goal-directed movement (i.

Postural limits of stability in premanifest and manifest Huntington's disease.

Background: Huntington's disease (HD) is associated with neuronal death in basal ganglia circuits important for postural control. Despite evidence of postural instability associated with HD, postural control at the limits of stability has not been investigated in this disease.

Objective: To use computerized dynamic posturography to measure postural control at the limits of stability during the premanifest and manifest stages of HD.

A novel MDMA analogue, UWA-101, that lacks psychoactivity and cytotoxicity, enhances L-DOPA benefit in parkinsonian primates.

Treatment of Parkinson's disease with dopaminergic agents, such as l-DOPA, is frequently compromised by disabling side effects, particularly dyskinesia and a shortening in duration of antiparkinsonian action. Studies in animal models and anecdotal evidence from a patient with Parkinson's disease show that the illicit drug ecstasy (MDMA) can alleviate these side effects, though with many drawbacks (e.g.

Proprioceptive recalibration in the right and left hands following abrupt visuomotor adaptation.

Previous studies have demonstrated that after reaching with misaligned visual feedback of the hand, one adapts his or her reaches and partially recalibrates proprioception, such that sense of felt hand position is shifted to match the seen hand position. However, to date, this has only been demonstrated in the right (dominant) hand following reach training with a visuomotor distortion in which the rotated cursor distortion was introduced gradually. As reach adaptation has been shown to differ depending on how the distortion is introduced (gradual vs.

Age-related source memory deficits persist despite superior item memory.

Source and item memory for faces of former United States Presidents were assessed in nondemented older adults over 65 years of age (n = 20) and young adults 18 to 25 years of age (n = 20). During the study phase, a male and a female source each presented pictures of faces to the participant one at a time. To assess source memory, the participant was asked to indicate whether a face from the study phase was presented by the male or female.

Proprioceptive recalibration following prolonged training and increasing distortions in visuomotor adaptation.

Reaching with misaligned visual feedback of the hand leads to reach adaptation (motor recalibration) and also results in partial sensory recalibration, where proprioceptive estimates of hand position are changed in a way that is consistent with the visual distortion. The goal of the present study was to explore the relationship between changes in sensory and motor systems by examining these processes following (1) prolonged reach training and (2) training with increasing visuomotor distortions. To examine proprioceptive recalibration, we determined the position at which subjects felt their hand was aligned with a reference marker after completing three blocks of reach training trials with a cursor that was rotated 30° clockwise (CW) for all blocks, or with a visuomotor distortion that was increased incrementally across the training blocks up to 70°CW relative to actual hand motion.

Postural deficits in Huntington's disease when performing motor skills involved in daily living.

Previous studies of Huntington's disease (HD) have reported motor control deficits for selected fine and gross motor skills. However, no studies have metrically assessed postural control in this clinical group when performing motor skills involved in daily living. Therefore, the purpose of the present study was to evaluate and compare postural control of individuals with confirmed Huntington's disease and non-gene carriers when completing three functional postural tasks.

Impaired postural stability as a marker of premanifest Huntington's disease.

Subtle changes in fine motor control have been observed in individuals who carry the Huntington's disease (HD) mutation but have not yet manifested symptoms, referred to as premanifest HD (preHD). However, few studies have examined gross motor impairments in this population. This study sought to examine the role of sensory involvement in maintaining postural stability during the premanifest and manifest stages of HD using computerized dynamic posturography.

Visuomotor adaptation and proprioceptive recalibration in older adults.

Previous studies have shown that both young and older subjects adapt their reaches in response to a visuomotor distortion. It has been suggested that one's continued ability to adapt to a visuomotor distortion with advancing age is due to the preservation of implicit learning mechanisms, where implicit learning mechanisms include processes that realign sensory inputs (i.e.