Paired-pulse and frequency potentiation of cortical responses in developing rats.
The postnatal development of paired-pulse and frequency potentiations of the first positive and negative components (P1N1) of the cortical interhemispheric response (IHR) was studied in urethane anesthetized rats aged from 7 to 90 days. The paired-pulse potentiation appeared in the rat sensorimotor cortex starting from the age of 15 days. The magnitude of potentiation increased with age. The interpulse interval inducing maximum potentiation shortened from 125 ms in 15-day-old rats to 70 ms in adult rats. Similar results concerning the paired-pulse responses were found for visual cortex but the maturation was somewhat delayed--potentiation first appeared at postnatal day (PND) 18. The frequency potentiation reached adult properties in the sensorimotor cortex by PND 25. There is no time coincidence in the development of the two potentiation phenomena studied, paired pulse potentiation appeared earlier than frequency potentiation.
Mares
P
P
Institute of Physiology, Czech Academy of Sciences, Prague.
Seidl
J
J
Pohl
M
M
D000818:Animals; D002540:Cerebral Cortex / Q000254:growth & development / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D009778:Occipital Lobe / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar