Fig. 2

Spreading depression (SD) induced by 200-Hz O-HFS of monophasic pulses in the rat hippocampal CA1 region. a and b Typical examples of recording signals in the CA1 pyramidal layer with 1-min 200-Hz O-HFS (denoted by the red bar) of biphasic pulses (a) or monophasic pulses (b). The pink shade in b denotes an SD event. The APS and OPS waveforms induced by A-test pulses at the alveus and by O-test pulses at the Schaffer collaterals in the periods before, during and after O-HFS are expanded. The small inverted triangle with a dotted line denotes an A-test pulse and the dot with a dotted line denotes an O-test pulse. The MUA signals in the periods before, during and after O-HFS were obtained by filtering the raw signals