Neurofibrillary

Neurofibrillary is an adjective used in neuroanatomy and neuropathology to describe structures derived from or related to the cytoskeletal network within neurons, particularly neurofibrils, which are composed of cytoplasmic filaments including tau-associated proteins. In common usage, the term most often appears in the name neurofibrillary tangles, intracellular aggregates linked to neurodegeneration.

Neurofibrillary tangles are formed when tau protein becomes abnormally hyperphosphorylated and detaches from microtubules, misfolds, and aggregates into paired helical filaments. These tangles accumulate inside neuronal cell bodies and dendrites, disrupt axonal transport, impair synaptic function, and contribute to neuronal death. NFTs are a hallmark of Alzheimer's disease and are observed in various tauopathies.

Progression is staged by Braak neurofibrillary tangle stages, beginning in the transentorhinal cortex and hippocampus and spreading to limbic and finally neocortical regions, often correlating with cognitive decline. The term neurofibrillary degeneration is used to describe the broader, progressive loss of neuronal cytoskeletal integrity due to tau pathology.

Beyond Alzheimer's disease, neurofibrillary pathology is found in other disorders including progressive supranuclear palsy, corticobasal degeneration, and frontotemporal dementia with tau pathology. In research and clinical practice, detecting NFTs through histology, imaging agents targeting tau, or cerebrospinal fluid biomarkers helps in diagnosis and in understanding disease progression.