Levodopa is known as the most effective drug for the treatment of Parkinson‘s disease. However, long-term use of levodopa usually is associated with levodopa-induced dyskinesia, which is mimicked chorea and dystonia. The abnormal involuntary movements sometimes develop troublesome for the patient‘s quality of life. Thus, revealing the pathomechanisms of levodopa-induced dyskinesia will be useful for the treatment of Parkinson‘s disease. It is considered that the key pathology of levodopa-induced dyskinesia is dopaminergic neuronal degeneration in the substantia nigra pers compacta. We revealed that the loss of dopaminergic neurons will be associated with levodopa-induced dyskinesia in vivo by using MRI neuromelanin imaging. Furthermore, we also revealed that the preservation of white matter structures, which are the connecting tracts between cortices and basal ganglia, might be important for developing levodopa-induced dyskinesia by using diffusion MRI. Finally, we revealed that the increasing GFAP positive astroglia in the striatum plays important role in the development of levodopa-induced dyskinesia in a rat model. In this symposium, we will show our data and discuss the pathomechanisms of levodopa-induced dyskinesia.