| Abstract: | Background firing activity was recorded in guinea pig neocortical slices maintained using extracellular techniques. Between 30 and 40% of neurons continued to generate action potentials, although at a reduced rate, when synaptic disruption had been induced by adenosine or adenosine 5-monophosphate action. These cells were classed as endogenously active. No connection could be shown between neuronal firing pattern and capacity for autonomous generation of action potentials. The remaining neurons tested remained inactive after synaptic disruption, but regained their capacity for spontaneous firing following washout. The activity of these cells was classified as exogenous (or the result of synaptic excitation induced by other neurons in the same slice). The majority of cells with a highly regular discharge pattern initially stopped discharging during synaptic blockade and resumed their activity following washout. This would suggest that a miniature excitatory circuit with 30–140 msec cycles operates in these slices.Institute of Biological Physics, Academy of Sciences of the USSR, Pushchino. Translated from Neirofiziologiya, Vol. 19, No. 6, pp. 816–824, November–December, 1987. |
