A current major hypothesis is that cognitive deficits, which accompanies neurodegenerative and neurodevelopmental disorders, may be associated with reduced trophic support of neuronal activity and survival by growth factors, including the neurotrophin Brain-Derived Neurotrophic Factor (BDNF). “Truncated” BDNF (truncBDNF) may play a specific role in neuronal plasticity and therefore may represent a specific serum biomarker of cognitive deficits. The study aims at shedding new light on the biological role of truncated BDNF as well as on receptor(s) interaction. In addition, we are studying methods for developing rapid and sensitive assay to measure truncated BDNF from serum samples. To obtain the 3D structure of truncBDNF, homology modeling approaches are used, which allow for the identification of sites which have the highest probability of interaction with receptors or antibodies.