Neurofilaments are the 10nm or intermediate filament proteins found specifically in neurons, and are composed predominantly of three major proteins called neurofilament light (NF-L), neurofilament medium (NF-M) and neurofilament heavy (NF-H). Neurofilament medium runs on SDS-PAGE gels in the range 145-170 kDa, with some variation in different species. Antibodies to this protein are useful to identify neurons and their processes in tissue sections and in tissue culture. Neurofilament medium can also be useful in studies of neurofilament accumulations seen in many neurological diseases, such as Lou Gehrig's disease or Alzheimer's disease.