In Parts I and II of this 2-part series, our aim was to utilize tissue autoradiography from the medulla of SIDS infants to further test the hypothesis that 5-HT1A and 5-HT2A/C receptor binding is altered in SIDS cases as compared to controls, which could underlie a failure to arouse and/or autoresuscitate leading to death. Here, HTR2A is linked to sudden infant death syndrome.