The present invention relates to an in vitro method for identifying a molecule, which interferes with the interaction between a glial cell-line derived neurotrophic factor family ligand (GFL) and a heparan sulfate proteoglycan (HSPG), by screening a library of molecules against a matrix anchored complex comprising at least one immobilized glial cell-line derived neurotrophic factor family ligand (GFL) and at least one heparan sulfate proteoglycan (HSPG), wherein the interfering molecule is isolated based on its capacity to replace a glial cell-line derived neurotrophic factor family ligand (GFL) in said anchored complex. The invention also relates to a complex for identifying such a molecule. The invention also relates to methods for preventing or delaying a neurodegenerative process as well as to method for prophylactic treatment or treatment of a disorder in the nervous system.