Study of Dopamine and Serotonin Transporters in Patients With Amyotrophic Lateral Sclerosis and Controls

The purpose of this study is to study the transporters of serotonin and dopamine in ALS patients in relation with the clinical phenotype, i.e., patients without stiffness, patients with pyramidal stiffness, patients with mixed (pyramidal and extra pyramidal) stiffness. For such a goal the investigators will use SPECT to compare the binding of two specific tracers in ALS patients and in matched healthy controls.