The aim of this work was to investigate ocular control in patients with optic ataxia (OA). Following a lesion in the posterior parietal cortex (PPC), these patients exhibit a deficit for fast visuo-motor control of reach-to-grasp movements. Here, we assessed the fast visuo-motor control of saccades as well as spontaneous eye-hand coordination in two bilateral OA patients and five neurologically...

The main aim of this study is to determine the reference frame of the pointing errors that characterize patients with unilateral optic ataxia (OA). The reaching errors of seven patients with unilateral OA when pointing on a 2D matrix in peripheral vision were investigated in order to better qualify the reference frame of their deficit. Patients were asked to fixate a central target and then to ...

Stroke patients with optic ataxia have an outstanding inability to perform spatially accurate movements to visual targets located in their peripheral visual field. Neuropsychological investigations of such patients contributed essentially to the two visual stream hypothesis which presumes dissociated actionand perception-related processing of visual information in the human brain. Here we revie...

Bálint’s syndrome is a clinical entity that combines variously a set of complex spatial behavior disorders following bilateral damage to the occipitoparietal junction. The core syndrome is a triad, composed of “optische Ataxie” – a defect of visually guided hand movements – “Seelenlähmung des Schauens” – often referred to as psychic paralysis of gaze or spasm of fixation – and “räumliche Storun...

A series of experiments documenting the reaching and grasping of two patients with optic ataxia is presented. We compare their immediate responses with their behavior when required to delay for a few seconds before responding. When the delayed response is 'pantomimed', i.e. made in the absence of the target object, their performance typically improves. This pattern was predicted from a two-visu...

We describe two new clinical syndromes, mirror agnosia and mirror ataxia, both characterized by the deficit of reaching for an object through a mirror in association with a lesion of either parietal lobe. Clinical investigation of 13 patients demonstrated that the impairments affected both sides of the body. In mirror agnosia, the patients always reached toward the virtual object in the mirror ...

Hereditary ataxias comprise a group of genetically heterogeneous disorders characterized by clinically variable cerebellar dysfunction and accompanied by involvement of other organ systems. The molecular underpinnings for many of these diseases are widely unknown. Previously, we discovered the disruption of Scyl1 as the molecular basis of the mouse mutant mdf, which is affected by neurogenic mu...