Motor learning tasks are often classified into adaptation tasks, which involve the recalibration of an existing control policy (the mapping that determines both feedforward and feedback commands), and skill-learning tasks, requiring the acquisition of new control policies. We show here that this distinction also applies to two different visuomotor transformations during reaching in humans: Mirr...

OBJECTIVE To report the visual outcome in patients with a neovascular membrane (NVM) associated with idiopathic juxtafoveolar telangiectasis (IJFT). METHODS We performed a retrospective, noncomparative analysis of 26 eyes of 16 patients with an NVM associated with bilateral IJFT (Gass classification group 2A). Eyes were divided into 2 groups: group WO (n = 11) included eyes with IJFT without ...

introduction: parkinson`s disease (pd) is a chronic disorder of basal ganglia with cardinal signs of resting tremor, bradykinesia, rigidity and postural instability. various studies have evaluated quiet stance postural stability in mild pd but as the authors know there is no consensus on this issue. therefore, the aim of this study was to evaluate stance stability of the subjects at early stage...

This study examined the effect of transformed visual feedback on movement control in Huntington's disease (HD). Patients in the early stages of HD and controls performed aiming movements towards peripheral targets on a digitizing tablet and emphasizing precision. In a baseline condition, HD patients were slower but showed few precision problems in aiming. When visual feedback was inverted in bo...

No previous study has simultaneously examined body ownership and agency in healthy subjects during mirror self-observation. We used a moving rubber hand illusion to examine how both body ownership and agency are affected by seeing (i) the body moving in a mirror, compared with (ii) directly viewing the moving hand, and (iii) seeing a visually identical hand rotated by 180°. We elicited ownershi...

Reaching movements to visual targets are under fast feedback control, which can rapidly correct an ongoing movement for errors. This study investigates how this online correction is affected by the application of a new visuomotor transformation. Thirty-two subjects made planar pointing movements to visual targets. Vision of the arm was prevented, and hand position was represented by a cursor di...

BACKGROUND The cerebellum integrates proprioceptive, vestibular and visual signals for postural control. Cerebellar patients with downbeat nystagmus (DBN) complain of unsteadiness of stance and gait as well as blurred vision and oscillopsia. OBJECTIVES The aim of this study was to elucidate the differential role of visual input, gaze eccentricity, vestibular and proprioceptive input on the po...

BACKGROUND Achieving independent upright posture has known to be one of the main goals in rehabilitation following lower limb amputation. The purpose of this study was to compare postural steadiness of below knee amputees with visual alterations while wearing three different prosthetic feet. METHODS Ten male below-knee amputees were instructed to stand quietly on the Biodex® balance platform ...