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Development of auditory brain-stem evoked responses (ABSR) in human infants and children
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increase in both components was not observed. About 25 min after the start of ischemia N markedly decreased in amplitude and prolon 6 ed in latency and duration. These changes in the NI amplitude were closely related to those of action potentials of the A-Bnerve fibers recorded from the ulnar sulcus simultaneously. By contrast, the P2 waves and action potentials of the A-o nerve fibers were more resistant to ischemia than those of the NI wave and the A-B fibers. These results may indicate that the A-B fiber is more sensitive to ischemia than the A-@fiber, and that most parts of the peripheral origins of N and P components of human evoked spinal cord botenti 2 1s are A- Band A- ofibers, respectively. C-6.01 HUMAN SPINAL CORD POTENTIALS EVOKED BY DESCENDING VOLLEYS ALONG THE SPINAL CORD. H. Shimizu, Y. Maruyama, H. Endo, S. Urano and K. Shimoji (Niigata, Japan) Epidural stimulation of the cervical cord produced not only spikes but also slow negativepositive complexes in the lumbar enlargement in normal subjects. The wave forms and the central latencies from the spikes of these slow negative (N)-positive (P) potentials elicited by the descending volleys were similar to those of the N and P waves evoked by segmental nerve st 1mulati.gn, which were thought to reflect interneuronal activities and primary afferent depolarization, respectively. With graded stimulation, both the slow positive wave evoked by the descending volleys and the segmentally evoked P2 wave grew quickly to reach maximum amplitudes at a weaker stimulus than that required for both the N and NI In the recovery curves, the P wave waves. evoked by descending volleys showed delayed recovery, lasting up to 100 msec. These characteristics of the N and P waves produced by descending volleys were similar to those of the N and P waves elicited by segmental nerve s 1.imulat 7 on. Thus, the N and P waves might respectively reflect the interneuronal activities and primary afferent depolarization elicited by descending volleys. C-5.03 HUMAN SPINAL CORD POTENTIALS AFFECTED BY THIAMYLAL, DIAZEPAM AND MORPHINE. Y.Maruyama, H. Shimizu, R. Kaieda, H. Kuribayashi and K. Shimoji (Niigata, Japan) The effects of thiamylal sodium, diazepam and morphine on the human spinal cord potentials (SCPs) evoked by segmental nerve volleys were studied in surgical patients who received a combination of general and epidural anesthesia.The fundamental pattern of the human SCP recorded from the posterior epidural space of the lumbar enlargement was very similar to that of the cord
dorsum potential (CDP) of animals directly recorded from the cord surface, and consisted of an initially oositive soike (P,). sharo neoative (N ) and slow'positive (P ) wa&. These"are believed to be the afferezt volleys, synchronous activites of interneurones, and primary afferent depolarization (PAD), respectively. Thiamylal sodium (10 mg/kg, i.v.) and diazepam (0.2 mg/kg, i.v.) exhibited similar effects on the human SCPs. A marked increase in both the amplitude and duration of P2 component was observed, indicating an enhancement of the segmentally elicited presynaptic inhibition. The amDlitude of N, was also auomented. The second component of P2 hisappeared. Morphine (1 mg/kg, i.v.) depressed the amplitude of all components and prolonged the half-decay time of the P wave, suggesting peripheral as well as centra ? effects of the drug. Naloxone (0.1 mg/kg) reversed these effects of morphine completely, partially or excessively. These depressant effects of morphine on human SCPs were minimized under N20 (75%) anesthesia, indicating an interaction between these two drugs.
D-12.02 DEVELOPMENT OF AUDITORY BRAIN-STEM EVOKED RESPONSES (ABSR) IN HUMAN INFANTS AND CHILDREN. Y. Mochizuki, T. Go. H. Ohkubo and T. Motomura (Shizuoka, Japan) The subjects consisted of 169 normal infants, children and young adults ranging in age from 36 weeks of gestation to 20 years. They were divided into 15 groups according to their age A total of 206 ABSR were obtained categories. from these subjects. ABSRs were recorded from disc electrodes placed at the surface of the mastoid process and a reference at the vertex. Click stimuli of 120 dB peSPL were presented binaurally at the rate of 13 clicks/set and 2048 responses were summated on line with an averThe results were as follows. I) Peak ager. I latency decreased rapidly until two months of age but no constant decreasing tendency was observed thereafter. 2) The peak I and V difference (V minus 1) showed a constant decreasing tendency-until 5 to 8 years of age. A statistically significant difference was noted between the 4 years group and the lo-20 years group 3) The amplitudes of peak I and peak (P'O.01). III reached the adult level at 9 months of sue. The amplitude of peak V became maximal at 4 years of age and showed a decreasing tendency thereafter. A-15.01 DO DOPAMINERGIC NEURONES MODULATE PHASIC MOTOR ACTIVITIES (PMA') IN REM SLEEP (REMs)? M. Segawa, Y. Nomura,'N. Shinomiya, Y. Suzuki, K. Honda, M. Ogiso and M. Sakamoto (Tokyo, Japan) The roles of dopaminergic neurones parameters are not known.
in sleep
increase in both components was not observed. About 25 min after the start of ischemia N markedly decreased in amplitude and prolon 6 ed in latency and duration. These changes in the NI amplitude were closely related to those of action potentials of the A-Bnerve fibers recorded from the ulnar sulcus simultaneously. By contrast, the P2 waves and action potentials of the A-o nerve fibers were more resistant to ischemia than those of the NI wave and the A-B fibers. These results may indicate that the A-B fiber is more sensitive to ischemia than the A-@fiber, and that most parts of the peripheral origins of N and P components of human evoked spinal cord botenti 2 1s are A- Band A- ofibers, respectively. C-6.01 HUMAN SPINAL CORD POTENTIALS EVOKED BY DESCENDING VOLLEYS ALONG THE SPINAL CORD. H. Shimizu, Y. Maruyama, H. Endo, S. Urano and K. Shimoji (Niigata, Japan) Epidural stimulation of the cervical cord produced not only spikes but also slow negativepositive complexes in the lumbar enlargement in normal subjects. The wave forms and the central latencies from the spikes of these slow negative (N)-positive (P) potentials elicited by the descending volleys were similar to those of the N and P waves evoked by segmental nerve st 1mulati.gn, which were thought to reflect interneuronal activities and primary afferent depolarization, respectively. With graded stimulation, both the slow positive wave evoked by the descending volleys and the segmentally evoked P2 wave grew quickly to reach maximum amplitudes at a weaker stimulus than that required for both the N and NI In the recovery curves, the P wave waves. evoked by descending volleys showed delayed recovery, lasting up to 100 msec. These characteristics of the N and P waves produced by descending volleys were similar to those of the N and P waves elicited by segmental nerve s 1.imulat 7 on. Thus, the N and P waves might respectively reflect the interneuronal activities and primary afferent depolarization elicited by descending volleys. C-5.03 HUMAN SPINAL CORD POTENTIALS AFFECTED BY THIAMYLAL, DIAZEPAM AND MORPHINE. Y.Maruyama, H. Shimizu, R. Kaieda, H. Kuribayashi and K. Shimoji (Niigata, Japan) The effects of thiamylal sodium, diazepam and morphine on the human spinal cord potentials (SCPs) evoked by segmental nerve volleys were studied in surgical patients who received a combination of general and epidural anesthesia.The fundamental pattern of the human SCP recorded from the posterior epidural space of the lumbar enlargement was very similar to that of the cord
dorsum potential (CDP) of animals directly recorded from the cord surface, and consisted of an initially oositive soike (P,). sharo neoative (N ) and slow'positive (P ) wa&. These"are believed to be the afferezt volleys, synchronous activites of interneurones, and primary afferent depolarization (PAD), respectively. Thiamylal sodium (10 mg/kg, i.v.) and diazepam (0.2 mg/kg, i.v.) exhibited similar effects on the human SCPs. A marked increase in both the amplitude and duration of P2 component was observed, indicating an enhancement of the segmentally elicited presynaptic inhibition. The amDlitude of N, was also auomented. The second component of P2 hisappeared. Morphine (1 mg/kg, i.v.) depressed the amplitude of all components and prolonged the half-decay time of the P wave, suggesting peripheral as well as centra ? effects of the drug. Naloxone (0.1 mg/kg) reversed these effects of morphine completely, partially or excessively. These depressant effects of morphine on human SCPs were minimized under N20 (75%) anesthesia, indicating an interaction between these two drugs.
D-12.02 DEVELOPMENT OF AUDITORY BRAIN-STEM EVOKED RESPONSES (ABSR) IN HUMAN INFANTS AND CHILDREN. Y. Mochizuki, T. Go. H. Ohkubo and T. Motomura (Shizuoka, Japan) The subjects consisted of 169 normal infants, children and young adults ranging in age from 36 weeks of gestation to 20 years. They were divided into 15 groups according to their age A total of 206 ABSR were obtained categories. from these subjects. ABSRs were recorded from disc electrodes placed at the surface of the mastoid process and a reference at the vertex. Click stimuli of 120 dB peSPL were presented binaurally at the rate of 13 clicks/set and 2048 responses were summated on line with an averThe results were as follows. I) Peak ager. I latency decreased rapidly until two months of age but no constant decreasing tendency was observed thereafter. 2) The peak I and V difference (V minus 1) showed a constant decreasing tendency-until 5 to 8 years of age. A statistically significant difference was noted between the 4 years group and the lo-20 years group 3) The amplitudes of peak I and peak (P'O.01). III reached the adult level at 9 months of sue. The amplitude of peak V became maximal at 4 years of age and showed a decreasing tendency thereafter. A-15.01 DO DOPAMINERGIC NEURONES MODULATE PHASIC MOTOR ACTIVITIES (PMA') IN REM SLEEP (REMs)? M. Segawa, Y. Nomura,'N. Shinomiya, Y. Suzuki, K. Honda, M. Ogiso and M. Sakamoto (Tokyo, Japan) The roles of dopaminergic neurones parameters are not known.
in sleep