NTRK2 and sudden infant death syndrome: Tang et al. evaluated the concentrations of BDNF and TrkB in a group of children who died of SIDS compared to non-SIDS children, and they noted lower BDNF values in the caudal nucleus of the solitary tract and higher TrkB expression in the caudal dorsal motor nucleus of the vagus in SIDS infants (Figure 1).