[Motor neglect of thalamic origin]

The clinical picture of thalamic motor neglect is identical to those of motor neglect in general, the major symptom of which being an underutilization of one side of the body in the absence of sensory-motor defect. Several thalamic nuclei can be implicated on the grounds of pathological and experimental data, most frequently the ventro-lateral nucleus. The prevalence of left neglect is not so obvious in the case of thalamic than in the case of other sites of lesions. Motor neglect appears as a disorder in the triggering of the brain structures network which program and prepare movement in several circumstances; attentional tasks are only a particular circumstance. Some thalamic nuclei are the site of hypoactivity in the case of frontal motor neglect in the monkey, as shown by anatomical and functional studies; this emphasizes the strong participation of thalamus to the motor network, the dysfunction of which can induce a motor neglect.