BDNF and Mental deterioration: Interestingly, in these patients, the postmortem cortex levels of BDNF were correlated with circulating serum BDNF levels, and the protein levels were associated with cognitive decline evaluated by the Mini Mental State Examination score (Poo, 2001; Michalski and Fahnestock, 2003; L. Tapia-Arancibia et al., 2008).