Sudden infant death syndrome in Hamburg. An epidemiological analysis of 150 cases.

A retrospective analysis was carried out of 150 SIDS cases seen in the five year period between 1979 and 1983 in Hamburg, Germany. The overall incidence was 2.3 per 1,000 live births. 82% of all infants and 100% of the preterm infants (corrected according to gestational age) dying of SIDS, died within the first 6 months of life. Infants of mothers less than 18 years of age, infants with more than 2 siblings, infants with birthweight less than 1,500 g and SGA-preterm infants were found to be high-risk subgroups. A high percentage (20% of all cases, 43% of infants with mothers less than 18 years) were underweight at death (under the 3rd weight-percentile). The study emphasizes the complexity of internal and external factors in the etiology of SIDS.

Activity and excitability to electrical current of cortical auditory receptive neurons of awake cats as affected by stimulus association.

1. Unit activity and excitability were studied at the midlateral and suprasylvian cortex of naive, blink-conditioned and "randomization" cats. The latter received the same CS and US as did the conditioned animals, but in random temporal order and with random intertrial intervals with mean comparable to that used for conditioning. The randomization group failed to develop a blink CR. 2. With conditioning, spontaneous and evoked unit discharges were increased above levels found in naive animals. Correspondingly, levels of extracellularly injected current required to elicit a spike discharge were lower in conditioned than in naive animals. In addition, in the conditioned animals, the degree of enhancement of evoked activity and excitability was found to be greatest in the units that responded to the CS, as opposed to units that responded to another auditory stimulus of equal intensity but of no special behavioral significance vis-a-vis the conditioned reflex. 3...