Spontaneous, synchronous electrical activity in neonatal mouse cortical neurones.
Spontaneous [Ca2+]i transients were measured in the mouse neocortex from embryonic day 16 (E16) to postnatal day 6 (P6). On the day of birth (P0), cortical neurones generated widespread, highly synchronous [Ca2+]i transients over large areas. On average, 52% of neurones participated in these transients, and in 20% of slices, an average of 80% participated. These transients were blocked by TTX and nifedipine, indicating that they resulted from Ca2+ influx during electrical activity, and occurred at a mean frequency of 0.91 min(-1). The occurrence of this activity was highly centred at P0: at E16 and P2 an average of only 15% and 24% of neurones, respectively, participated in synchronous transients, and they occurred at much lower frequencies at both E16 and P2 than at P0. The overall frequency of [Ca2+]i transients in individual cells did not change between E16 and P2, just the degree of their synchronicity. The onset of this spontaneous, synchronous activity correlated with a large increase in Na+ current density that occurred just before P0, and its cessation with a large decrease in resting resistance that occurred just after P2. This widespread, synchronous activity may serve a variety of functions in the neonatal nervous system.
Department of Biology, University of Washington, Seattle, WA 98115, USA.
Rebekah
R
Corlew
Martha M
MM
Bosma
William J
WJ
Moody
D000375:Aging / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism; D002540:Cerebral Cortex / Q000166:cytology / Q000196:embryology / Q000378:metabolism / Q000502:physiology*; D004594:Electrophysiology; D004622:Embryo, Mammalian / Q000187:drug effects / Q000502:physiology; D047108:Embryonic Development; D007425:Intracellular Membranes / Q000378:metabolism; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009994:Osmolar Concentration; D011930:Reaction Time / Q000187:drug effects; D019789:Tetraethylammonium / Q000494:pharmacology
D019789:Tetraethylammonium; D002118:Calcium