Temporal Dynamics of Distinct CA1 Cell Populations during Unconscious State Induced by Ketamine
(A) Spike rasters of silmultanously recorded pyramidal cells (blue) and type-5 interneuron (an example unit plotted is in red, and other type-5 interneurons in orange) after ketamine injection, during running and slow-wave sleep are shown (left subpanels). The cross-correlation functions of the interneuron and pyramidal cell joint-activities are plotted on the right. The black line is the cross-correlation during the awake rest state. (B) The basic properties of this type-5 unit. The most upper left panel shows the average spike waveforms. Firing probability histograms suggest that the neuronal firing timing showed slight correlation with theta oscillations but was not coupled to ripple oscillations (middle left and lower left panels). (C) Autocorrelograms in different states: after ketamine injection, during running, and during sleep respectively. Autocorrelograms are shown in two time scales: 0–50 ms and 0–1.5 sec. Note the slow oscillatory dynamics-induced by ketamine is evident in both cross-correlation plot (the top right corner plot in A) and the longer time scale autocorrelogram (bottom left corner plot in C).