Neurosurgery, or neurological surgery, is a medical specialty related to prevention, diagnosis, surgical treatment, and recovery of disorders that affect any part of the nervous system including the brain, spinal cord, peripheral nerves, and extra cranial cerebrovascular systems. Neuropathology is specialized in pathology studies that focus on brain disease, spinal cord, and nerve tissue. This includes the central nervous system and the peripheral nervous system. Tissue analysis comes from any surgical biopsy or post mortem autopsy. Examples of regular tissue include muscle fibers and nerve tissue. Regular neuropathological applications include studying tissue samples in patients with Parkinson's disease, Alzheimer's disease, dementia, Huntington's disease, amyotrophic lateral sclerosis, mitochondrial disease, and any nerve disorders in the brain or spinal cord.