Impulsive-compulsive behaviors (ICBs), one of the non-motor symptoms of Parkinson′s disease (PD), may be attributed to dopaminergic dysfunction and dopamine replacement therapy. At present, understanding of ICBs, mechanisms and exploration of treatment largely depend on neuroimaging research. Despite contradictions among the findings, most evidence indicated that PD patients with ICBs showed decreased thickness in frontal and temporal cortex and the volume of subcortical nuclei when compared to those without ICBs. And the occurrence of ICBs is associated with relatively preserved white-matter integrity in the brain regions involved in reward-related behaviors. This article will give an overview of the magnetic resonance research of PD related ICBs including cortical thickness, diffusion tensor imaging, resting state and task state functional magnetic resonance imaging analysis, which lays a foundation for further imaging studies, revealing the pathogenesis and exploring the potential treatment options.

Distal hereditary motor neuropathy (dHMN) is a group of clinically and genetically heterogeneous disorders characterized by progressive distal weakness and atrophy. The onset of dHMN is at mid-adulthood or early childhood, and the symptoms are mainly present in the lower limbs. Besides weakness and atrophy of distal limb muscles, some patients may develop bulbar paralysis, and some may also present with mild sensory disturbance. Decreased or absent tendon reflexes may be discovered. Electromyography may show neurogenic damages. Muscular biopsy may reveal neurogenic amyotrophy. An increasing number of genes have been associated with dHMN. Pathogenesis of dHMN may include formation of protein aggregates, impairment of autophagy pathway, RNA processing, translation synthesis, axonal transport, endoplasmic reticulum stress, calcium channel and neuroprotection. A review for recent progress made on clinical characterization and molecular genetics of dHMN is provided.