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. Author manuscript; available in PMC: 2014 Jun 1.
Published in final edited form as: Neurobiol Dis. 2013 Mar 4;54:68–81. doi: 10.1016/j.nbd.2013.02.009

Figure 2. Pathologic HFOs are apparent throughout the Kcna1-null hippocampus.

Figure 2

(A) Power spectra of SPWs in the CA3sr illustrating the sharp ripple peak present in both WT and KO hippocampal slices, whereas the broad fast ripple peak appears only in the KO spectrum. (B) Representative SPWs from the CA3sr region of a WT and a KO slice filtered to demonstrate the presence/absence of high frequency oscillations (HFOs), specifically ripples at 100–175 Hz and fast ripples at 200–600 Hz. Lower panel, Time-frequency representation of the component frequencies of the SPWs band-pass filtered between 100–600 Hz. (C) Ripple duration and cycles per ripple are increased, whereas intra-ripple frequency is decreased in KO slices (n = 11) compared to WT slices (n = 11). Fast ripple durations, cycles and intra-fast ripple frequency are also presented for KO slices, but are not detectable (ND) in WT slices. ***p<0.001. (D) Representative illustrations of spatial maps of the presence of ripples and fast ripples for individual slices. The presence of HFOs was determined by generating power spectra and time-frequency representations of five-ten minute recordings from each electrode. Ripples are widespread in hippocampi of both genotypes. Fast ripples are prevalent only in KO hippocampi and do not spread into the entorhinal cortex. We performed similar spatial maps of HFOs for 3–5 slices per microelectrode array size for each genotype and always found similar patterns as those presented.