AGE-RELATED ELECTROCORTICOGRAPHIC AND RESPIRATORY ADAPTATION TO REPEATED HYPOXIA

Severe hypoxia is known to produce depression in electrical brain acti vity and perturbation of respiratory pattern. In piglets undergoing ch ronic recording of brain and respiratory muscle activities, a depresse d electrocorticogram (ECoG) was observed in response to rapidly induce d (<30 s), brief (10 min), and moderate hypoxia (10% O-2 in 90% N-2) i n 16 out of 42 study sessions in young (3- to 11-day-old) animals only . Responses to hypoxia were monitored over 4 consecutive days. In five cases, the latency to the onset of the ECoG depression increased prog ressively over the 4 test days, and its duration decreased progressive ly. An associated respiratory gasping pattern also exhibited gradual r emission over consecutive days. These changes in the responses to repe ated hypoxia demonstrate adaptation of mechanisms underlying neuronal perturbation by oxygen deprivation.