Among possible explanations for this unexplained discrepancy are the differential age-related synaptic loss and associated cognitive decline after reduced gene expression of brain-derived neurotrophic factor (BDNF) and its neurotrophic receptor tyrosine kinase 2—NTRK2 (also known as TRKB) activity, which recapitulates the age-like pattern of expression markers of GABA inhibitory presynaptic genes [29]. Here, NTRK2 is linked to Mental deterioration.