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. 2017 Aug 23;37(34):8166–8179. doi: 10.1523/JNEUROSCI.3456-16.2017

Figure 5.

Figure 5.

Expression of ΔFosB in the hippocampal formation after spontaneous seizures induced by AAV-TeLC injection. To identify neurons stimulated during spontaneous seizures, sections of the ventral hippocampus were obtained after EEG monitoring (up to 8 weeks after AAV-TeLC or AAV-GFP injection) and labeled for ΔFosB-immunoreactivity, a cellular marker accumulating in activated neurons (Morris et al., 2000). A, D, Only very faint ΔFosB labeling was detected in some neurons of the hippocampal formation (A), including the subiculum (D; higher magnification) in AAV-GFP-injected mice (no EEG alterations) and in AAV-TeLC-injected mice with C-SWDs but no SRSs (data not shown). B, C, E, F, ΔFosB was clearly expressed in the neurons of mice that experienced one to six SRSs (B) and high numbers of ΔFosB-positive neurons were present throughout the hippocampal formation and the deep and superficial layers of the entorhinal and perirhinal cortices of mice that had experienced between 9 and 19 SRSs after AAV-TeLC (C, E, F). E, Higher magnification of the subiculum of these mice. C, F, Note the extremely strong expression of ΔFosB in the granule cell layer of these mice (C), sometimes particularly concentrated in the inner and outer portions of the granule cell layer (F). G–J, Semiquantitative estimates of ΔFosB-positive cells using the ImageJ program were done in blinded fashion and are depicted in sector CA3 (G), granule cells of the dentate gyrus (H), the subiculum (I), and layers V to VI of the perirhinal cortex after injection of AAV-GFP (GFP; n = 10) or AAV-TeLC (TeLC; J). AAV-TeLC-injected mice had experienced at most C-SWDs (TeLC sw; n = 9) or 1–6 (TeLC rs+; n = 10) or more frequent (9–19) SRSs (TeLC rs++, n = 5). Scale bars: C (for A–C), 500 μm; F (for D–F), 100 μm. Similar increases in numbers of ΔFosB-positive neurons were also obtained for sector CA1, the superficial layers of the perirhinal cortex (PRC), and the deep and superficial entorhinal cortices (data not shown). Statistical analyses were conducted using the Kruskal–Wallis test with Dunn's multiple-comparison post hoc test (all groups compared with controls; *p < 0.05; **p < 0.01; ***p < 0.001 vs AAV-GFP group). Values are given as the mean ± SEM. CA1 and CA3, Hippocampal sectors CA1 and CA3; DG, dentate gyrus; EC, entorhinal cortex; PRC, perirhinal cortex; Sub, subiculum.