To produce hand's movement directed towards a target, the investigator must combine several sensory information, such as vision or proprioception. The posterior parietal cortex (PPC) is a region of the cortex involved in this multisensory integration. A lesion of the PPC cause a visuo-motor trouble called optic ataxia but these patients also have perceptual troubles.

The aim of the study is to understand the different functions of the PPC and especially how the processes of spatial coding of the sensory information influences perception and motor planning.

In this study, the investigator want to explore the sensory motor and the perceptual performance of patients with optic ataxia compared with healthy subjects, using 6 behavioral tests.

Objectify the consequences of PPC impairment (visual-motor and perceptual consequences) on patients' quality of life and autonomy.

Inclusion Criteria:

All patients and healthy subjects:

• male and female, age from 18 to 75 years included
• normal vision or corrected vision
• covered by social security
• signed written informed consent

Patients:

• neurological injury in posterior parietal cortex supported by a cerebral MRI
• present optic ataxia symptoms Healthy subjects
• no known neurological injury

Exclusion Criteria:

- unable to comply with the tasks (neurological, psychiatric, sensory or motor troubles)