2016 年 33 巻 2 号 p. 186-190
The development of large data sets and more powerful computers over the last decade have made it possible to reveal the fundamental principles of complex functional and anatomical brain networks using several techniques. Resting state functional magnetic resonance imaging (rsfMRI), a non–invasive tool to assess functional abnormalities of the brain without specific motor or cognitive tasks, has provided important insight into the pathophysiology of normal aging and neurodegenerative disorders. Results of our preliminary analysis of 200 aged healthy subjects indicate that brain atrophy with aging is observed mainly in limbic and premotor areas. Diffusion tract imaging showed anatomical network disruption surrounding the lateral ventricle. However, rsfMRI showed that an increase of resting connectivity across multiple cortical areas was observed more frequently than a decrease. These results may reflect a compensatory phenomenon of functional brain networks against the progression of brain atrophy and disruption of anatomical brain networks with aging. The IMAGEN group demonstrated that dozens of genes linked to ion channel activity and synaptic function support connectivity functional resting state networks. These molecular components may become new targets for disease modifying therapy. In addition, rsfMRI revealed that replacement therapy, deep brain stimulation, and rehabilitation may assist the normalization or amelioration of abnormal functional network connectivities and improve symptoms in neurodegenerative disorders. Analysis of brain functional connectivity may play an important clinical role as an early diagnostic and biomarker tool.