The goal of this proposal is to study the development of chemical control of ventilation in the infant monkey: in particular to focus on the effect on ventilatory control of maturation (as determined by gestational and postnatal age) activity or sleep state (as determined by electrophysiologic recordings, including electroencephalogram, electrooculogram and electromyogram) and central nervous system biogenic amine activity. Quantitation of the ventilatory response (with a hot-wire anemometer) to stimuli (hypoxia and/or hypercapnia) will be accomplished at specific gestational and postnatal ages. Important variables, including arterial blood gases and pH and sleep state, will be carefully documented. Mechanisms and/or potential therapeutic modalities will be explored via manipulation of central nervous system biogenic amine levels. This investigation is of potential importance to a more clear understanding of pathophysiologic mechanisms that may be important in the etiology of neonatal-apnea and/or the Sudden Infant Death Syndrome.