. . "brain-derived neurotrophic factor" . "BDNF gene" . . . . "neurotrophic factor gene" . . . . "Bdnf" . . "brain-derived neurotrophic factor (BDNF)" . "BNDF" . "brain derived neurotrophic factor" . "exon IV" . . "Brain-derived_neurotrophic_factor" . "Brain-derived neurotrophic factor (BDNF)" . "bdnf" . "Brain-derived neurotrophic factor" . . "''BDNF''" . . . . . "BDNF (brain-derived neurotrophic factor)" . . "Brain Derived Neurotrophic Factor" . "BDNF" . . "neurotrophic BDNF" . "Brain-derived neurotrophic factor" . . . .