Figure 2.

Effects of tissue oxygenation on spontaneous network activity and evoked local field potential responses in CA3. A, Multiunit activity was recorded continuously in stratum pyramidale, and oxygenation was changed according to the protocol as illustrated in B. B, Applying single-unit discrimination in recording periods of 180 s, single units were classified in three groups according to their spike rates (spikes/s), which revealed a distribution of 10% (solid line), 22% (dotted line), and 68% (dashed line) (from n = 69) at 95% O₂ (gray background). Note that the spike rates declined in all groups at 20% O₂ (white background), which was reversible. C, After 15 min under the respective oxygenation condition, local field potential responses (fp) were evoked orthodromically by application of single electrical stimuli to the fiber tracts from dentate gyrus to CA3. Note that there were no differences in shape and amplitude (see Results) of the responses. *p < 0.05.