photomicrograph shows brown-immunostained alpha-synuclein in Lewy bodies (large clumps) and Lewy neurites (thread-like structures) in the neocortical tissue of a person who died with Lewy body disease. DLB is characterized by the development of abnormal collections of alpha-synuclein protein within diseased brain neurons, manifesting as Lewy bodies and Lewy neurites. When these clumps of protein form, neurons function less optimally and eventually die. Neuronal loss in DLB leads to profound dopamine dysfunction and marked cholinergic pathology; other neurotransmitters might be affected, but less is known about them. Damage in the brain is widespread, and affects many domains of functioning. Loss of acetylcholine-producing neurons is thought to account for degeneration in memory and learning, while the death of dopamine-producing neurons appears to be responsible for degeneration of behavior, cognition, mood, movement, motivation, and sleep. The extent of Lewy body neuronal damage is a key determinant of dementia in the Lewy body disorders. The precise mechanisms contributing to DLB are not well understood and are a matter of some controversy. The role of alpha-synuclein deposits is unclear, because individuals with no signs of DLB have been found on autopsy to have advanced alpha-synuclein pathology. The relationship between Lewy pathology and widespread cell death is contentious. It is not known if the pathology spreads between cells or follows another pattern. The mechanisms that contribute to cell death, how the disease advances through the brain, and the timing of cognitive decline are all poorly understood. There is no model to account for the specific neurons and brain regions that are affected. Autopsy studies and amyloid imaging studies using Pittsburgh compound B (PiB) indicate that tau protein pathology and amyloid plaques, which are hallmarks of AD, are also common in DLB and more common than in Parkinson's disease dementia. Amyloid-beta (Aβ) deposits are found in the tauopathies—neurodegenerative diseases characterized by neurofibrillary tangles of hyperphosphorylated tau protein—but the mechanism underlying dementia is often mixed, and Aβ is also a factor in DLB. A proposed pathophysiology for RBD implicates neurons in the reticular formation that regulate REM sleep. RBD might appear decades earlier than other symptoms in the Lewy body dementias because these cells are affected earlier, before spreading to other brain regions.
medical cause of Parkinsonism
medical cause of Dementia
symptom of Pantothenate kinase-associated neurodegeneration
complications of Myotonic dystrophy
symptom of Amyotrophic lateral sclerosis
symptom of Spinocerebellar ataxia type 1
medical cause of Polyneuropathy
medical cause of Dystonia