[The role of electrophysiological properties of neurons in mechanisms of discharge grouping in the cortex].
Properties of intracellular discharges of pyramidal cells of layers II/III and V in rat neocortex were in detail studied in vitro. Neuronal firing was evoked by depolarizing 1-3-min current injection (0.1-1.0 nA) into the neurons (N = 80). The so-called spike sequences with regular increasing or decreasing interspike intervals were analyzed. Number of spikes in a sequence (5-30% of recorded total spike number) and oscillation amplitude of their afterhyperpolarization potential (0-1.5 mV) were significantly correlated with their mean firing frequency. The dependence of spike number in a sequence on the mean spike frequency was of biphasic character with the critical frequency in the range of 5-7 Hz. Cells with and without depolarization component during afterhyperpolarization had different morphological and electrophysiological properties, but the dependence of their spike number in a sequence on the spike mean frequency was of similar character. A possible role of the revealed characteristics of spike sequences in generation of cortical rhythms is discussed.
Karpuk
N N
NN
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino.
Vorob'ev
V V
VV
D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography; D007425:Intracellular Membranes / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D009044:Motor Cortex / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D013003:Somatosensory Cortex / Q000502:physiology; D013826:Theta Rhythm