New Neural Brain-to-bone pathway Controls Skeletal Development

Within the past year researchers at the Hebrew University of Jerusalem that a part of the autonomic nervous system reaches bones and takes a part in controlling bone development. The new pathway has a part in controlling bone density during the adolescence years and determines the skeletal resistance to fractures throughout the whole life span. In the autonomic nervous system, the brain monitors and regulates the physiological functions of the internal organs and includes two subsystems, the "symphatic" and "parasymphatic.  Each have their own neural pathways. Sympahtic system helps in times of danger or with stress. The parasympahtic helps with digestion, and immune function. The researchers demonstrated that there are parasympahtic responses in the skeleton. A weakened rabies virus was injected into thigh bones of mice. After the injection, the virus was seen in the brain in regions know to be specific for the parasymphatic subsystem. In past research, the activity of the protein interleukin-1 was found to influence bone development. This influence is similar to the parasymphatic system. The recent discovered neural pathway which includes interleukin-1 in the brain and the parasymphatic subsystem, also control heart rate. Having conditions such as depression, osteoporosis, and epilepsy can damage interleukin-1 and the parasymphatic system  in the brain. Finding the disease mechanism in these cases can have a potential for new therapy development. This new pathway is only a small key to understanding the connection between the brain and the bones.