What are four unique principles that relate to the localization and distribution of nervous system function which influence the clinical and pathologic manifestations of neurologic disease:
1. The nervous system is vulnerable to focal lesions, which is compounded by the limited ability of the nervous system to regenerate following inury.2. Because there is localization of function in the nervous system, the same pathologic process can present clinically different when a different part of the system is affected. Conversely, different diseases affecting the same area of the nervous system will present clinically similar. A meningioma at the base of the brain may compress the optic nerve and lead to blindness.Yet, a meningioma in the lateral cortex may lead to seizures and a meningioma in the medulla may cause a head tilt.A choroid plexus tumor, infarct, or inflammation affecting the medulla may also lead to a head tilt.3. Groups of neurons are selectively vulnerable to different diseases.Because the nervous system is comprised of different types of cells, different toxins will affect different groups of neurons, which results in a specific pattern of pathologic changes.4. The response of the nervous system to injury is limited and non-specific, so the diagnosis often depends on the location of the injury rather than the microscopic appearance of the lesion.